NAME¶
CGI::Simple - A Simple totally OO CGI interface that is CGI.pm compliant
VERSION¶
This document describes CGI::Simple version 1.113.
SYNOPSIS¶
use CGI::Simple;
$CGI::Simple::POST_MAX = 1024; # max upload via post default 100kB
$CGI::Simple::DISABLE_UPLOADS = 0; # enable uploads
$q = new CGI::Simple;
$q = new CGI::Simple( { 'foo'=>'1', 'bar'=>[2,3,4] } );
$q = new CGI::Simple( 'foo=1&bar=2&bar=3&bar=4' );
$q = new CGI::Simple( \*FILEHANDLE );
$q->save( \*FILEHANDLE ); # save current object to a file as used by new
@params = $q->param; # return all param names as a list
$value = $q->param('foo'); # return the first value supplied for 'foo'
@values = $q->param('foo'); # return all values supplied for foo
%fields = $q->Vars; # returns untied key value pair hash
$hash_ref = $q->Vars; # or as a hash ref
%fields = $q->Vars("|"); # packs multiple values with "|" rather than "\0";
@keywords = $q->keywords; # return all keywords as a list
$q->param( 'foo', 'some', 'new', 'values' ); # set new 'foo' values
$q->param( -name=>'foo', -value=>'bar' );
$q->param( -name=>'foo', -value=>['bar','baz'] );
$q->param( 'foo', 'some', 'new', 'values' ); # append values to 'foo'
$q->append( -name=>'foo', -value=>'bar' );
$q->append( -name=>'foo', -value=>['some', 'new', 'values'] );
$q->delete('foo'); # delete param 'foo' and all its values
$q->delete_all; # delete everything
<INPUT TYPE="file" NAME="upload_file" SIZE="42">
$files = $q->upload() # number of files uploaded
@files = $q->upload(); # names of all uploaded files
$filename = $q->param('upload_file') # filename of uploaded file
$mime = $q->upload_info($filename,'mime'); # MIME type of uploaded file
$size = $q->upload_info($filename,'size'); # size of uploaded file
my $fh = $q->upload($filename); # get filehandle to read from
while ( read( $fh, $buffer, 1024 ) ) { ... }
# short and sweet upload
$ok = $q->upload( $q->param('upload_file'), '/path/to/write/file.name' );
print "Uploaded ".$q->param('upload_file')." and wrote it OK!" if $ok;
$decoded = $q->url_decode($encoded);
$encoded = $q->url_encode($unencoded);
$escaped = $q->escapeHTML('<>"&');
$unescaped = $q->unescapeHTML('<>"&');
$qs = $q->query_string; # get all data in $q as a query string OK for GET
$q->no_cache(1); # set Pragma: no-cache + expires
print $q->header(); # print a simple header
# get a complex header
$header = $q->header( -type => 'image/gif'
-nph => 1,
-status => '402 Payment required',
-expires =>'+24h',
-cookie => $cookie,
-charset => 'utf-7',
-attachment => 'foo.gif',
-Cost => '$2.00'
);
# a p3p header (OK for redirect use as well)
$header = $q->header( -p3p => 'policyref="http://somesite.com/P3P/PolicyReferences.xml' );
@cookies = $q->cookie(); # get names of all available cookies
$value = $q->cookie('foo') # get first value of cookie 'foo'
@value = $q->cookie('foo') # get all values of cookie 'foo'
# get a cookie formatted for header() method
$cookie = $q->cookie( -name => 'Password',
-values => ['superuser','god','my dog woofie'],
-expires => '+3d',
-domain => '.nowhere.com',
-path => '/cgi-bin/database',
-secure => 1
);
print $q->header( -cookie=>$cookie ); # set cookie
print $q->redirect('http://go.away.now'); # print a redirect header
dienice( $q->cgi_error ) if $q->cgi_error;
DESCRIPTION¶
CGI::Simple provides a relatively lightweight drop in replacement for CGI.pm. It
shares an identical OO interface to CGI.pm for parameter parsing, file upload,
cookie handling and header generation. This module is entirely object
oriented, however a complete functional interface is available by using the
CGI::Simple::Standard module.
Essentially everything in CGI.pm that relates to the CGI (not HTML) side of
things is available. There are even a few new methods and additions to old
ones! If you are interested in what has gone on under the hood see the
Compatibility with CGI.pm section at the end.
In practical testing this module loads and runs about twice as fast as CGI.pm
depending on the precise task.
CALLING CGI::Simple ROUTINES USING THE OBJECT INTERFACE¶
Here is a very brief rundown on how you use the interface. Full details follow.
First you need to initialize an object¶
Before you can call a CGI::Simple method you must create a CGI::Simple object.
You do that by using the module and then calling the
new() constructor:
use CGI::Simple;
my $q = new CGI::Simple;
It is traditional to call your object $q for query or perhaps $cgi.
Next you call methods on that object¶
Once you have your object you can call methods on it using the -> arrow
syntax For example to get the names of all the parameters passed to your
script you would just write:
@names = $q->param();
Many methods are sensitive to the context in which you call them. In the example
above the
param() method returns a list of all the
parameter names when called without any arguments.
When you call
param('arg') with a single argument it assumes you want to
get the value(s) associated with that argument (parameter). If you ask for an
array it gives you an array of all the values associated with it's argument:
@values = $q->param('foo'); # get all the values for 'foo'
whereas if you ask for a scalar like this:
$value = $q->param('foo'); # get only the first value for 'foo'
then it returns only the first value (if more than one value for 'foo' exists).
Most CGI::Simple routines accept several arguments, sometimes as many as 10
optional ones! To simplify this interface, all routines use a named argument
calling style that looks like this:
print $q->header( -type=>'image/gif', -expires=>'+3d' );
Each argument name is preceded by a dash. Neither case nor order matters in the
argument list. -type, -Type, and -TYPE are all acceptable.
Several routines are commonly called with just one argument. In the case of
these routines you can provide the single argument without an argument name.
header() happens to be one of these routines. In
this case, the single argument is the document type.
print $q->header('text/html');
Sometimes methods expect a scalar, sometimes a reference to an array, and
sometimes a reference to a hash. Often, you can pass any type of argument and
the routine will do whatever is most appropriate. For example, the
param() method can be used to set a CGI parameter
to a single or a multi-valued value. The two cases are shown below:
$q->param(-name=>'veggie',-value=>'tomato');
$q->param(-name=>'veggie',-value=>['tomato','tomahto','potato','potahto']);
CALLING CGI::Simple ROUTINES USING THE FUNCTION INTERFACE¶
For convenience a functional interface is provided by the CGI::Simple::Standard
module. This hides the OO details from you and allows you to simply call
methods. You may either use AUTOLOADING of methods or import specific method
sets into you namespace. Here are the first few examples again using the
function interface.
use CGI::Simple::Standard qw(-autoload);
@names = param();
@values = param('foo');
$value = param('foo');
print header(-type=>'image/gif',-expires=>'+3d');
print header('text/html');
Yes that's it. Not a $q-> in sight. You just use the module and select
how/which methods to load. You then just call the methods you want exactly as
before but without the $q-> notation.
When (if) you read the following docs and are using the functional interface
just pretend the $q-> is not there.
Selecting which methods to load¶
When you use the functional interface Perl needs to be able to find the
functions you call. The simplest way of doing this is to use autoloading as
shown above. When you use CGI::Simple::Standard with the '-autoload' pragma it
exports a single AUTOLOAD sub into you namespace. Every time you call a non
existent function AUTOLOAD is called and will load the required function and
install it in your namespace. Thus only the AUTOLOAD sub and those functions
you specifically call will be imported.
Alternatively CGI::Simple::Standard provides a range of function sets you can
import or you can just select exactly what you want. You do this using the
familiar
use CGI::Simple::Standard qw( :func_set some_func);
notation. This will import the ':func_set' function set and the specific
function 'some_func'.
To Autoload or not to Autoload, that is the question.¶
If you do not have a AUTOLOAD sub in you script it is generally best to use the
'-autoload' option. Under autoload you can use any method you want but only
import and compile those functions you actually use.
If you do not use autoload you must specify what functions to import. You can
only use functions that you have imported. For comvenience functions are
grouped into related sets. If you choose to import one or more ':func_set' you
may have potential namespace collisions so check out the docs to see what gets
imported. Using the ':all' tag is pretty slack but it is there if you want.
Full details of the function sets are provided in the CGI::Simple::Standard
docs
If you just want say the param and header methods just load these two.
use CGI::Simple::Standard qw(param header);
Setting globals using the functional interface¶
Where you see global variables being set using the syntax:
$CGI::Simple::DEBUG = 1;
You use exactly the same syntax when using CGI::Simple::Standard.
THE CORE METHODS¶
new() Creating a new query object¶
The first step in using CGI::Simple is to create a new query object using the
new() constructor:
$q = new CGI::Simple;
This will parse the input (from both POST and GET methods) and store it into an
object called $q.
If you provide a file handle to the
new() method, it
will read parameters from the file (or STDIN, or whatever).
open FH, "test.in" or die $!;
$q = new CGI::Simple(\*FH);
open $fh, "test.in" or die $!;
$q = new CGI::Simple($fh);
The file should be a series of newline delimited TAG=VALUE pairs. Conveniently,
this type of file is created by the
save() method
(see below). Multiple records can be saved and restored. IO::File objects work
fine.
If you are using the function-oriented interface provided by
CGI::Simple::Standard and want to initialize from a file handle, the way to do
this is with
restore_parameters(). This will
(re)initialize the default CGI::Simple object from the indicated file handle.
restore_parameters(\*FH);
In fact for all intents and purposes
restore_parameters() is identical to
new() Note that
restore_parameters() does not exist in
CGI::Simple itself so you can't use it.
You can also initialize the query object from an associative array reference:
$q = new CGI::Simple( { 'dinosaur' => 'barney',
'song' => 'I love you',
'friends' => [qw/Jessica George Nancy/] }
);
or from a properly formatted, URL-escaped query string:
$q = new CGI::Simple( 'dinosaur=barney&color=purple' );
or from a previously existing CGI::Simple object (this generates an identical
clone including all global variable settings, etc that are stored in the
object):
$old_query = new CGI::Simple;
$new_query = new CGI::Simple($old_query);
To create an empty query, initialize it from an empty string or hash:
$empty_query = new CGI::Simple("");
-or-
$empty_query = new CGI::Simple({});
keywords() Fetching a list of keywords from a query¶
@keywords = $q->keywords;
If the script was invoked as the result of an <ISINDEX> search, the parsed
keywords can be obtained as an array using the
keywords() method.
param() Fetching the names of all parameters passed to
your script¶
@names = $q->param;
If the script was invoked with a parameter list (e.g.
"name1=value1&name2=value2&name3=value3"), the
param() method will return the parameter names as
a list. If the script was invoked as an <ISINDEX> script and contains a
string without ampersands (e.g. "value1+value2+value3") , there will
be a single parameter named "keywords" containing the
"+"-delimited keywords.
NOTE: The array of parameter names returned will be in the same order as they
were submitted by the browser. Usually this order is the same as the order in
which the parameters are defined in the form (however, this isn't part of the
spec, and so isn't guaranteed).
param() Fetching the value or values of a simple named
parameter¶
@values = $q->param('foo');
-or-
$value = $q->param('foo');
Pass the
param() method a single argument to fetch
the value of the named parameter. If the parameter is multi-valued (e.g. from
multiple selections in a scrolling list), you can ask to receive an array.
Otherwise the method will return a single value.
If a value is not given in the query string, as in the queries
"name1=&name2=" or "name1&name2", it will be
returned by default as an empty string. If you set the global variable:
$CGI::Simple::NO_UNDEF_PARAMS = 1;
Then value-less parameters will be ignored, and will not exist in the query
object. If you try to access them via param you will get an undef return
value.
param() Setting the values of a named parameter¶
$q->param('foo','an','array','of','values');
This sets the value for the named parameter 'foo' to an array of values. This is
one way to change the value of a field.
param() also recognizes a named parameter style of
calling described in more detail later:
$q->param(-name=>'foo',-values=>['an','array','of','values']);
-or-
$q->param(-name=>'foo',-value=>'the value');
If POSTed or PUTed data is not of type application/x-www-form-urlencoded or
multipart/form-data, then the data will not be processed, but instead be
returned as-is in a parameter named POSTDATA or PUTDATA. To retrieve it, use
code like this:
my $data = $q->param( 'POSTDATA' );
-or-
my $data = $q->param( 'PUTDATA' );
(If you don't know what the preceding means, don't worry about it. It only
affects people trying to use CGI::Simple for REST webservices)
add_param() Setting the values of a named parameter¶
You nay also use the new method
add_param to add parameters. This is an
alias to the
_add_param() internal method that actually does all the
work. You can call it like this:
$q->add_param('foo', 'new');
$q->add_param('foo', [1,2,3,4,5]);
$q->add_param( 'foo', 'bar', 'overwrite' );
The first argument is the parameter, the second the value or an array ref of
values and the optional third argument sets overwrite mode. If the third
argument is absent of false the values will be appended. If true the values
will overwrite any existing ones
append() Appending values to a named parameter¶
$q->append(-name=>'foo',-values=>['yet','more','values']);
This adds a value or list of values to the named parameter. The values are
appended to the end of the parameter if it already exists. Otherwise the
parameter is created. Note that this method only recognizes the named argument
calling syntax.
import_names() Importing all parameters into a
namespace.¶
This method was silly, non OO and has been deleted. You can get all the params
as a hash using
Vars or via all the other accessors.
delete() Deleting a parameter completely¶
$q->delete('foo');
This completely clears a parameter. If you are using the function call
interface, use
Delete() instead to avoid conflicts
with Perl's built-in delete operator.
If you are using the function call interface, use
Delete() instead to avoid conflicts with Perl's
built-in delete operator.
delete_all() Deleting all parameters¶
$q->delete_all();
This clears the CGI::Simple object completely. For CGI.pm compatibility
Delete_all() is provided however there is no
reason to use this in the function call interface other than symmetry.
For CGI.pm compatibility
Delete_all() is provided as
an alias for
delete_all however there is no reason to use this, even in
the function call interface.
param_fetch() Direct access to the parameter list¶
This method is provided for CGI.pm compatibility only. It returns an array ref
to the values associated with a named param. It is deprecated.
Vars() Fetching the entire parameter list as a hash¶
$params = $q->Vars; # as a tied hash ref
print $params->{'address'};
@foo = split "\0", $params->{'foo'};
%params = $q->Vars; # as a plain hash
print $params{'address'};
@foo = split "\0", $params{'foo'};
%params = $q->Vars(','); # specifying a different separator than "\0"
@foo = split ',', $params{'foo'};
Many people want to fetch the entire parameter list as a hash in which the keys
are the names of the CGI parameters, and the values are the parameters'
values. The
Vars() method does this.
Called in a scalar context, it returns the parameter list as a tied hash
reference. Because this hash ref is tied changing a key/value changes the
underlying CGI::Simple object.
Called in a list context, it returns the parameter list as an ordinary hash.
Changing this hash will not change the underlying CGI::Simple object
When using
Vars(), the thing you must watch out for
are multi-valued CGI parameters. Because a hash cannot distinguish between
scalar and list context, multi-valued parameters will be returned as a packed
string, separated by the "\0" (null) character. You must split this
packed string in order to get at the individual values. This is the convention
introduced long ago by Steve Brenner in his cgi-lib.pl module for Perl version
4.
You can change the character used to do the multiple value packing by passing it
to
Vars() as an argument as shown.
url_param() Access the QUERY_STRING regardless of 'GET' or
'POST'¶
The
url_param() method makes the QUERY_STRING data
available regardless of whether the REQUEST_METHOD was 'GET' or 'POST'. You
can do anything with
url_param that you can do with
param() , however the data set is completely
independent.
Technically what happens if you use this method is that the QUERY_STRING data is
parsed into a new CGI::Simple object which is stored within the current
object.
url_param then just calls
param()
on this new object.
parse_query_string() Add QUERY_STRING data to 'POST'
requests¶
When the REQUEST_METHOD is 'POST' the default behavior is to ignore name/value
pairs or keywords in the $ENV{'QUERY_STRING'}. You can override this by
calling
parse_query_string() which will add the
QUERY_STRING data to the data already in our CGI::Simple object if the
REQUEST_METHOD was 'POST'
$q = new CGI::Simple;
$q->parse_query_string; # add $ENV{'QUERY_STRING'} data to our $q object
If the REQUEST_METHOD was 'GET' then the QUERY_STRING will already be stored in
our object so
parse_query_string will be ignored.
This is a new method in CGI::Simple that is not available in CGI.pm
save() Saving the state of an object to file¶
$q->save(\*FILEHANDLE)
This will write the current state of the form to the provided filehandle. You
can read it back in by providing a filehandle to the
new() method.
The format of the saved file is:
NAME1=VALUE1
NAME1=VALUE1'
NAME2=VALUE2
NAME3=VALUE3
=
Both name and value are URL escaped. Multi-valued CGI parameters are represented
as repeated names. A session record is delimited by a single = symbol. You can
write out multiple records and read them back in with several calls to
new().
open FH, "test.in" or die $!;
$q1 = new CGI::Simple(\*FH); # get the first record
$q2 = new CGI::Simple(\*FH); # get the next record
Note: If you wish to use this method from the function-oriented (non-OO)
interface, the exported name for this method is
save_parameters() . Also if you want to initialize
from a file handle, the way to do this is with
restore_parameters() . This will (re)initialize
the default CGI::Simple object from the indicated file handle.
restore_parameters(\*FH);
FILE UPLOADS¶
File uploads are easy with CGI::Simple. You use the
upload() method. Assuming you have the following
in your HTML:
<FORM
METHOD="POST"
ACTION="http://somewhere.com/cgi-bin/script.cgi"
ENCTYPE="multipart/form-data">
<INPUT TYPE="file" NAME="upload_file1" SIZE="42">
<INPUT TYPE="file" NAME="upload_file2" SIZE="42">
</FORM>
Note that the ENCTYPE is "multipart/form-data". You must specify this
or the browser will default to "application/x-www-form-urlencoded"
which will result in no files being uploaded although on the surface things
will appear OK.
When the user submits this form any supplied files will be spooled onto disk and
saved in temporary files. These files will be deleted when your script.cgi
exits so if you want to keep them you will need to proceed as follows.
upload() The key file upload method¶
The
upload() method is quite versatile. If you call
upload() without any arguments it will return a
list of uploaded files in list context and the number of uploaded files in
scalar context.
$number_of_files = $q->upload;
@list_of_files = $q->upload;
Having established that you have uploaded files available you can get the
browser supplied filename using
param() like this:
$filename1 = $q->param('upload_file1');
You can then get a filehandle to read from by calling
upload() and supplying this filename as an
argument. Warning: do not modify the value you get from
param() in any way - you don't need to untaint
it.
$fh = $q->upload( $filename1 );
Now to save the file you would just do something like:
$save_path = '/path/to/write/file.name';
open FH, ">$save_path" or die "Oops $!\n";
binmode FH;
print FH $buffer while read( $fh, $buffer, 4096 );
close FH;
By utilizing a new feature of the upload method this process can be simplified
to:
$ok = $q->upload( $q->param('upload_file1'), '/path/to/write/file.name' );
if ($ok) {
print "Uploaded and wrote file OK!";
} else {
print $q->cgi_error();
}
As you can see upload will accept an optional second argument and will write the
file to this file path. It will return 1 for success and undef if it fails. If
it fails you can get the error from
cgi_error
You can also use just the fieldname as an argument to upload ie:
$fh = $q->upload( 'upload_field_name' );
or
$ok = $q->upload( 'upload_field_name', '/path/to/write/file.name' );
BUT there is a catch. If you have multiple upload fields, all called
'upload_field_name' then you will only get the last uploaded file from these
fields.
upload_info() Get the details about uploaded files¶
The
upload_info() method is a new method. Called
without arguments it returns the number of uploaded files in scalar context
and the names of those files in list context.
$number_of_upload_files = $q->upload_info();
@filenames_of_all_uploads = $q->upload_info();
You can get the MIME type of an uploaded file like this:
$mime = $q->upload_info( $filename1, 'mime' );
If you want to know how big a file is before you copy it you can get that
information from
uploadInfo which will return the file size in bytes.
$file_size = $q->upload_info( $filename1, 'size' );
The size attribute is optional as this is the default value returned.
Note: The old CGI.pm
uploadInfo() method has been
deleted.
$POST_MAX and $DISABLE_UPLOADS¶
CGI.pm has a default setting that allows infinite size file uploads by default.
In contrast file uploads are disabled by default in CGI::Simple to discourage
Denial of Service attacks. You must enable them before you expect file uploads
to work.
When file uploads are disabled the file name and file size details will still be
available from
param() and
upload_info
respectively but the upload filehandle returned by
upload() will be undefined - not surprising as
the underlying temp file will not exist either.
You can enable uploads using the '-upload' pragma. You do this by specifying
this in you use statement:
use CGI::Simple qw(-upload);
Alternatively you can enable uploads via the $DISABLE_UPLOADS global like this:
use CGI::Simple;
$CGI::Simple::DISABLE_UPLOADS = 0;
$q = new CGI::Simple;
If you wish to set $DISABLE_UPLOADS you must do this *after* the use statement
and *before* the new constructor call as shown above.
The maximum acceptable data via post is capped at 102_400kB rather than infinity
which is the CGI.pm default. This should be ample for most tasks but you can
set this to whatever you want using the $POST_MAX global.
use CGI::Simple;
$CGI::Simple::DISABLE_UPLOADS = 0; # enable uploads
$CGI::Simple::POST_MAX = 1_048_576; # allow 1MB uploads
$q = new CGI::Simple;
If you set to -1 infinite size uploads will be permitted, which is the CGI.pm
default.
$CGI::Simple::POST_MAX = -1; # infinite size upload
Alternatively you can specify all the CGI.pm default values which allow file
uploads of infinite size in one easy step by specifying the '-default' pragma
in your use statement.
use CGI::Simple qw( -default ..... );
binmode() and Win32¶
If you are using CGI::Simple be sure to call
binmode() on any handle that you create to write
the uploaded file to disk. Calling
binmode() will
do no harm on other systems anyway.
MISCELANEOUS METHODS¶
escapeHTML() Escaping HTML special characters¶
In HTML the < > " and & chars have special meaning and need to be
escaped to < > " and & respectively.
$escaped = $q->escapeHTML( $string );
$escaped = $q->escapeHTML( $string, 'new_lines_too' );
If the optional second argument is supplied then newlines will be escaped to.
unescapeHTML() Unescape HTML special characters¶
This performs the reverse of
escapeHTML().
$unescaped = $q->unescapeHTML( $HTML_escaped_string );
url_decode() Decode a URL encoded string¶
This method will correctly decode a url encoded string.
$decoded = $q->url_decode( $encoded );
url_encode() URL encode a string¶
This method will correctly URL encode a string.
$encoded = $q->url_encode( $string );
parse_keywordlist() Parse a supplied keyword list¶
@keywords = $q->parse_keywordlist( $keyword_list );
This method returns a list of keywords, correctly URL escaped and split out of
the supplied string
put() Send output to browser¶
CGI.pm alias for print. $q->put('Hello World!') will print the usual
print() Send output to browser¶
CGI.pm alias for print. $q->print('Hello World!') will print the usual
HTTP COOKIES¶
CGI.pm has several methods that support cookies.
A cookie is a name=value pair much like the named parameters in a CGI query
string. CGI scripts create one or more cookies and send them to the browser in
the HTTP header. The browser maintains a list of cookies that belong to a
particular Web server, and returns them to the CGI script during subsequent
interactions.
In addition to the required name=value pair, each cookie has several optional
attributes:
- 1. an expiration time
- This is a time/date string (in a special GMT format) that
indicates when a cookie expires. The cookie will be saved and returned to
your script until this expiration date is reached if the user exits the
browser and restarts it. If an expiration date isn't specified, the cookie
will remain active until the user quits the browser.
- 2. a domain
- This is a partial or complete domain name for which the
cookie is valid. The browser will return the cookie to any host that
matches the partial domain name. For example, if you specify a domain name
of ".capricorn.com", then the browser will return the cookie to
Web servers running on any of the machines "www.capricorn.com",
"www2.capricorn.com", "feckless.capricorn.com", etc.
Domain names must contain at least two periods to prevent attempts to
match on top level domains like ".edu". If no domain is
specified, then the browser will only return the cookie to servers on the
host the cookie originated from.
- 3. a path
- If you provide a cookie path attribute, the browser will
check it against your script's URL before returning the cookie. For
example, if you specify the path "/cgi-bin", then the cookie
will be returned to each of the scripts "/cgi-bin/tally.pl",
"/cgi-bin/order.pl", and
"/cgi-bin/customer_service/complain.pl", but not to the script
"/cgi-private/site_admin.pl". By default, path is set to
"/", which causes the cookie to be sent to any CGI script on
your site.
- 4. a "secure" flag
- If the "secure" attribute is set, the cookie will
only be sent to your script if the CGI request is occurring on a secure
channel, such as SSL.
cookie() A simple access method to cookies¶
The interface to HTTP cookies is the
cookie()
method:
$cookie = $q->cookie( -name => 'sessionID',
-value => 'xyzzy',
-expires => '+1h',
-path => '/cgi-bin/database',
-domain => '.capricorn.org',
-secure => 1
);
print $q->header(-cookie=>$cookie);
cookie() creates a new cookie. Its parameters
include:
- -name
- The name of the cookie (required). This can be any string
at all. Although browsers limit their cookie names to non-whitespace
alphanumeric characters, CGI.pm removes this restriction by escaping and
unescaping cookies behind the scenes.
- -value
- The value of the cookie. This can be any scalar value,
array reference, or even associative array reference. For example, you can
store an entire associative array into a cookie this way:
$cookie=$q->cookie( -name => 'family information',
-value => \%childrens_ages );
- -path
- The optional partial path for which this cookie will be
valid, as described above.
- -domain
- The optional partial domain for which this cookie will be
valid, as described above.
- -expires
- The optional expiration date for this cookie. The format is
as described in the section on the header()
method:
"+1h" one hour from now
- -secure
- If set to true, this cookie will only be used within a
secure SSL session.
The cookie created by
cookie() must be incorporated
into the HTTP header within the string returned by the
header() method:
print $q->header(-cookie=>$my_cookie);
To create multiple cookies, give
header() an array
reference:
$cookie1 = $q->cookie( -name => 'riddle_name',
-value => "The Sphynx's Question"
);
$cookie2 = $q->cookie( -name => 'answers',
-value => \%answers
);
print $q->header( -cookie => [ $cookie1, $cookie2 ] );
To retrieve a cookie, request it by name by calling
cookie() method without the
-value
parameter:
use CGI::Simple;
$q = new CGI::Simple;
$riddle = $q->cookie('riddle_name');
%answers = $q->cookie('answers');
Cookies created with a single scalar value, such as the "riddle_name"
cookie, will be returned in that form. Cookies with array and hash values can
also be retrieved.
The cookie and CGI::Simple namespaces are separate. If you have a parameter
named 'answers' and a cookie named 'answers', the values retrieved by
param() and
cookie()
are independent of each other. However, it's simple to turn a CGI parameter
into a cookie, and vice-versa:
# turn a CGI parameter into a cookie
$c = $q->cookie( -name=>'answers', -value=>[$q->param('answers')] );
# vice-versa
$q->param( -name=>'answers', -value=>[$q->cookie('answers')] );
raw_cookie()¶
Returns the HTTP_COOKIE variable. Cookies have a special format, and this method
call just returns the raw form (?cookie dough). See
cookie() for ways of setting and retrieving
cooked cookies.
Called with no parameters,
raw_cookie() returns the
packed cookie structure. You can separate it into individual cookies by
splitting on the character sequence "; ". Called with the name of a
cookie, retrieves the
unescaped form of the cookie. You can use the
regular
cookie() method to get the names, or use
the
raw_fetch() method from the CGI::Simmple::Cookie module.
Normally the first thing you will do in any CGI script is print out an HTTP
header. This tells the browser what type of document to expect, and gives
other optional information, such as the language, expiration date, and whether
to cache the document. The header can also be manipulated for special
purposes, such as server push and pay per view pages.
print $q->header;
-or-
print $q->header('image/gif');
-or-
print $q->header('text/html','204 No response');
-or-
print $q->header( -type => 'image/gif',
-nph => 1,
-status => '402 Payment required',
-expires => '+3d',
-cookie => $cookie,
-charset => 'utf-7',
-attachment => 'foo.gif',
-Cost => '$2.00'
);
header() returns the Content-type: header. You can
provide your own MIME type if you choose, otherwise it defaults to text/html.
An optional second parameter specifies the status code and a human-readable
message. For example, you can specify 204, "No response" to create a
script that tells the browser to do nothing at all.
The last example shows the named argument style for passing arguments to the CGI
methods using named parameters. Recognized parameters are
-type,
-status,
-cookie,
-target,
-expires,
-nph,
-charset and
-attachment. Any other named parameters will be
stripped of their initial hyphens and turned into header fields, allowing you
to specify any HTTP header you desire.
For example, you can produce non-standard HTTP header fields by providing them
as named arguments:
print $q->header( -type => 'text/html',
-nph => 1,
-cost => 'Three smackers',
-annoyance_level => 'high',
-complaints_to => 'bit bucket'
);
This will produce the following non-standard HTTP header:
HTTP/1.0 200 OK
Cost: Three smackers
Annoyance-level: high
Complaints-to: bit bucket
Content-type: text/html
Note that underscores are translated automatically into hyphens. This feature
allows you to keep up with the rapidly changing HTTP "standards".
The
-type is a key element that tell the browser how to display your
document. The default is 'text/html'. Common types are:
text/html
text/plain
image/gif
image/jpg
image/png
application/octet-stream
The
-status code is the HTTP response code. The default is 200 OK. Common
status codes are:
200 OK
204 No Response
301 Moved Permanently
302 Found
303 See Other
307 Temporary Redirect
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
405 Not Allowed
408 Request Timed Out
500 Internal Server Error
503 Service Unavailable
504 Gateway Timed Out
The
-expires parameter lets you indicate to a browser and proxy server
how long to cache pages for. When you specify an absolute or relative
expiration interval with this parameter, some browsers and proxy servers will
cache the script's output until the indicated expiration date. The following
forms are all valid for the -expires field:
+30s 30 seconds from now
+10m ten minutes from now
+1h one hour from now
-1d yesterday (i.e. "ASAP!")
now immediately
+3M in three months
+10y in ten years time
Thursday, 25-Apr-1999 00:40:33 GMT at the indicated time & date
The
-cookie parameter generates a header that tells the browser to
provide a "magic cookie" during all subsequent transactions with
your script. Netscape cookies have a special format that includes interesting
attributes such as expiration time. Use the
cookie() method to create and retrieve session
cookies.
The
-target is for frames use
The
-nph parameter, if set to a true value, will issue the correct
headers to work with a NPH (no-parse-header) script. This is important to use
with certain servers that expect all their scripts to be NPH.
The
-charset parameter can be used to control the character set sent to
the browser. If not provided, defaults to ISO-8859-1. As a side effect, this
sets the
charset() method as well.
The
-attachment parameter can be used to turn the page into an
attachment. Instead of displaying the page, some browsers will prompt the user
to save it to disk. The value of the argument is the suggested name for the
saved file. In order for this to work, you may have to set the
-type to
'application/octet-stream'.
no_cache() Preventing browser caching of scripts¶
Most browsers will not cache the output from CGI scripts. Every time the browser
reloads the page, the script is invoked anew. However some browsers do cache
pages. You can discourage this behavior using the
no_cache() function.
$q->no_cache(1); # turn caching off by sending appropriate headers
$q->no_cache(1); # do not send cache related headers.
$q->no_cache(1);
print header (-type=>'image/gif', -nph=>1);
This will produce a header like the following:
HTTP/1.0 200 OK
Server: Apache - accept no substitutes
Expires: Thu, 15 Nov 2001 03:37:50 GMT
Date: Thu, 15 Nov 2001 03:37:50 GMT
Pragma: no-cache
Content-Type: image/gif
Both the Pragma: no-cache header field and an Expires header that corresponds to
the current time (ie now) will be sent.
cache() Preventing browser caching of scripts¶
The somewhat ill named
cache() method is a legacy
from CGI.pm. It operates the same as the new
no_cache() method. The difference is/was that when
set it results only in the Pragma: no-cache line being printed. Expires time
data is not sent.
print $q->redirect('http://somewhere.else/in/movie/land');
Sometimes you don't want to produce a document yourself, but simply redirect the
browser elsewhere, perhaps choosing a URL based on the time of day or the
identity of the user.
The
redirect() function redirects the browser to a
different URL. If you use redirection like this, you should
not print
out a header as well.
One hint I can offer is that relative links may not work correctly when you
generate a redirection to another document on your site. This is due to a
well-intentioned optimization that some servers use. The solution to this is
to use the full URL (including the http: part) of the document you are
redirecting to.
You can also use named arguments:
print $q->redirect( -uri=>'http://somewhere.else/in/movie/land',
-nph=>1
);
The
-nph parameter, if set to a true value, will issue the correct
headers to work with a NPH (no-parse-header) script. This is important to use
with certain servers, such as Microsoft ones, which expect all their scripts
to be NPH.
PRAGMAS¶
There are a number of pragmas that you can specify in your use CGI::Simple
statement. Pragmas, which are always preceded by a hyphen, change the way that
CGI::Simple functions in various ways. You can generally achieve exactly the
same results by setting the underlying $GLOBAL_VARIABLES.
For example the '-upload' pargma will enable file uploads:
use CGI::Simple qw(-upload);
In CGI::Simple::Standard Pragmas, function sets , and individual functions can
all be imported in the same
use() line. For example, the following use
statement imports the standard set of functions and enables debugging mode
(pragma -debug):
use CGI::Simple::Standard qw(:standard -debug);
The current list of pragmas is as follows:
- -no_undef_params
- If a value is not given in the query string, as in the
queries "name1=&name2=" or "name1&name2", by
default it will be returned as an empty string.
If you specify the '-no_undef_params' pragma then CGI::Simple ignores
parameters with no values and they will not appear in the query
object.
- -nph
- This makes CGI.pm produce a header appropriate for an NPH
(no parsed header) script. You may need to do other things as well to tell
the server that the script is NPH. See the discussion of NPH scripts
below.
- -newstyle_urls
- Separate the name=value pairs in CGI parameter query
strings with semicolons rather than ampersands. For example:
?name=fred;age=24;favorite_color=3
Semicolon-delimited query strings are always accepted, but will not be
emitted by self_url() and query_string() unless the
-newstyle_urls pragma is specified.
- -oldstyle_urls
- Separate the name=value pairs in CGI parameter query
strings with ampersands rather than semicolons. This is the default.
?name=fred&age=24&favorite_color=3
- -autoload
- This is only available for CGI::Simple::Standard and uses
AUTOLOAD to load functions on demand. See the CGI::Simple::Standard docs
for details.
- -no_debug
- This turns off the command-line processing features. This
is the default.
- -debug1 and debug2
- This turns on debugging. At debug level 1 CGI::Simple will
read arguments from the command-line. At debug level 2 CGI.pm will produce
the prompt "(offline mode: enter name=value pairs on standard
input)" and wait for input on STDIN. If no number is specified then a
debug level of 2 is used.
See the section on debugging for more details.
- -default
- This sets the default global values for CGI.pm which will
enable infinite size file uploads, and specify the '-newstyle_urls' and
'-debug1' pragmas
- -no_upload
- Disable uploads - the default setting
- - upload
- Enable uploads - the CGI.pm default
- -unique_header
- Only allows headers to be generated once per script
invocation
- -carp
- Carp when cgi_error() called,
default is to do nothing
- -croak
- Croak when cgi_error() called,
default is to do nothing
USING NPH SCRIPTS¶
NPH, or "no-parsed-header", scripts bypass the server completely by
sending the complete HTTP header directly to the browser. This has slight
performance benefits, but is of most use for taking advantage of HTTP
extensions that are not directly supported by your server, such as server push
and PICS headers.
Servers use a variety of conventions for designating CGI scripts as NPH. Many
Unix servers look at the beginning of the script's name for the prefix
"nph-". The Macintosh WebSTAR server and Microsoft's Internet
Information Server, in contrast, try to decide whether a program is an NPH
script by examining the first line of script output.
CGI.pm supports NPH scripts with a special NPH mode. When in this mode, CGI.pm
will output the necessary extra header information when the
header() and
redirect() methods are called. You can set NPH
mode in any of the following ways:
- In the use statement
- Simply add the "-nph" pragma to the use:
use CGI::Simple qw(-nph)
- By calling the nph()
method:
- Call nph() with a non-zero
parameter at any point after using CGI.pm in your program.
$q->nph(1)
- By using -nph parameters
- in the header() and
redirect() statements:
print $q->header(-nph=>1);
The Microsoft Internet Information Server requires NPH mode. CGI::Simple will
automatically detect when the script is running under IIS and put itself into
this mode. You do not need to do this manually, although it won't hurt
anything if you do. However, note that if you have applied Service Pack 6,
much of the functionality of NPH scripts, including the ability to redirect
while setting a cookie, b<do not work at all> on IIS without a special
patch from Microsoft. See
http://support.microsoft.com/support/kb/articles/Q280/3/41.ASP: Non-Parsed
Headers Stripped From CGI Applications That Have nph- Prefix in Name.
SERVER PUSH¶
CGI.pm provides four simple functions for producing multipart documents of the
type needed to implement server push. These functions were graciously provided
by Ed Jordan <ed@fidalgo.net> with additions from Andrew Benham
<adsb@bigfoot.com>
You are also advised to put the script into NPH mode and to set $| to 1 to avoid
buffering problems.
Browser support for server push is variable.
Here is a simple script that demonstrates server push:
#!/usr/local/bin/perl
use CGI::Simple::Standard qw/:push -nph/;
$| = 1;
print multipart_init(-boundary=>'----here we go!');
foreach (0 .. 4) {
print multipart_start(-type=>'text/plain'),
"The current time is ",scalar(localtime),"\n";
if ($_ < 4) {
print multipart_end;
}
else {
print multipart_final;
}
sleep 1;
}
This script initializes server push by calling
multipart_init() . It then enters a loop in which
it begins a new multipart section by calling
multipart_start() , prints the current local time,
and ends a multipart section with
multipart_end().
It then sleeps a second, and begins again. On the final iteration, it ends the
multipart section with
multipart_final() rather
than with
multipart_end().
multipart_init() Initialize the multipart system¶
multipart_init(-boundary=>$boundary);
Initialize the multipart system. The -boundary argument specifies what MIME
boundary string to use to separate parts of the document. If not provided,
CGI.pm chooses a reasonable boundary for you.
multipart_start() Start a new part of the multipart
document¶
multipart_start(-type=>$type)
Start a new part of the multipart document using the specified MIME type. If not
specified, text/html is assumed.
multipart_end() End a multipart part¶
multipart_end()
End a part. You must remember to call
multipart_end() once for each
multipart_start() , except at the end of the last
part of the multipart document when
multipart_final() should be called instead of
multipart_end().
multipart_final()¶
multipart_final()
End all parts. You should call
multipart_final()
rather than
multipart_end() at the end of the last
part of the multipart document.
CGI::Push¶
Users interested in server push applications should also have a look at the
CGI::Push module.
DEBUGGING¶
If you are running the script from the command line or in the perl debugger, you
can pass the script a list of keywords or parameter=value pairs on the command
line or from standard input (you don't have to worry about tricking your
script into reading from environment variables). Before you do this you will
need to change the debug level from the default level of 0 (no debug) to
either 1 if you want to debug from @ARGV (the command line) of 2 if you want
to debug from STDIN. You can do this using the debug pragma like this:
use CGI::Simple qw(-debug2); # set debug to level 2 => from STDIN
or this:
$CGI::Simple::DEBUG = 1; # set debug to level 1 => from @ARGV
At debug level 1 you can pass keywords and name=value pairs like this:
your_script.pl keyword1 keyword2 keyword3
or this:
your_script.pl keyword1+keyword2+keyword3
or this:
your_script.pl name1=value1 name2=value2
or this:
your_script.pl name1=value1&name2=value2
At debug level 2 you can feed newline-delimited name=value pairs to the script
on standard input. You will be presented with the following prompt:
(offline mode: enter name=value pairs on standard input)
You end the input with your system dependent end of file character. You should
try ^Z ^X ^D and ^C if all else fails. The ^ means hold down the [Ctrl] button
while you press the other key.
When debugging, you can use quotes and backslashes to escape characters in the
familiar shell manner, letting you place spaces and other funny characters in
your parameter=value pairs:
your_script.pl "name1='I am a long value'" "name2=two\ words"
Dump() Dumping the current object details¶
The
Dump() method produces a string consisting of
all the query's object attributes formatted nicely as a nested list. This dump
includes the name/value pairs and a number of other details. This is useful
for debugging purposes:
print $q->Dump
The actual result of this is HTML escaped formatted text wrapped in <pre>
tags so if you send it straight to the browser it produces something that
looks like:
$VAR1 = bless( {
'.parameters' => [
'name',
'color'
],
'.globals' => {
'FATAL' => -1,
'DEBUG' => 0,
'NO_NULL' => 1,
'POST_MAX' => 102400,
'USE_CGI_PM_DEFAULTS' => 0,
'HEADERS_ONCE' => 0,
'NPH' => 0,
'DISABLE_UPLOADS' => 1,
'NO_UNDEF_PARAMS' => 0,
'USE_PARAM_SEMICOLONS' => 0
},
'.fieldnames' => {
'color' => '1',
'name' => '1'
},
'.mod_perl' => '',
'color' => [
'red',
'green',
'blue'
],
'name' => [
'JaPh,'
]
}, 'CGI::Simple' );
You may recognize this as valid Perl syntax (which it is) and/or the output from
Data::Dumper (also true). This is the actual guts of how the information is
stored in the query object. All the internal params start with a . char
Alternatively you can dump your object and the current environment using:
print $q->Dump(\%ENV);
PrintEnv() Dumping the environment¶
You can get a similar browser friendly dump of the current %ENV hash using:
print $q->PrintEnv;
This will produce something like (in the browser):
$VAR1 = {
'QUERY_STRING' => 'name=JaPh%2C&color=red&color=green&color=blue',
'CONTENT_TYPE' => 'application/x-www-form-urlencoded',
'REGRESSION_TEST' => 'simple.t.pl',
'VIM' => 'C:\\WINDOWS\\Desktop\\vim',
'HTTP_REFERER' => 'xxx.sex.com',
'HTTP_USER_AGENT' => 'LWP',
'HTTP_ACCEPT' => 'text/html;q=1, image/gif;q=0.42, */*;q=0.001',
'REMOTE_HOST' => 'localhost',
'HTTP_HOST' => 'the.restaurant.at.the.end.of.the.universe',
'GATEWAY_INTERFACE' => 'bleeding edge',
'REMOTE_IDENT' => 'None of your damn business',
'SCRIPT_NAME' => '/cgi-bin/foo.cgi',
'SERVER_NAME' => 'nowhere.com',
'HTTP_COOKIE' => '',
'CONTENT_LENGTH' => '42',
'HTTPS_A' => 'A',
'HTTP_FROM' => 'spammer@nowhere.com',
'HTTPS_B' => 'B',
'SERVER_PROTOCOL' => 'HTTP/1.0',
'PATH_TRANSLATED' => '/usr/local/somewhere/else',
'SERVER_SOFTWARE' => 'Apache - accept no substitutes',
'PATH_INFO' => '/somewhere/else',
'REMOTE_USER' => 'Just another Perl hacker,',
'REMOTE_ADDR' => '127.0.0.1',
'HTTPS' => 'ON',
'DOCUMENT_ROOT' => '/vs/www/foo',
'REQUEST_METHOD' => 'GET',
'REDIRECT_QUERY_STRING' => '',
'AUTH_TYPE' => 'PGP MD5 DES rot13',
'COOKIE' => 'foo=a%20phrase; bar=yes%2C%20a%20phrase&;I%20say;',
'SERVER_PORT' => '8080'
};
cgi_error() Retrieving CGI::Simple error messages¶
Errors can occur while processing user input, particularly when processing
uploaded files. When these errors occur, CGI::Simple will stop processing and
return an empty parameter list. You can test for the existence and nature of
errors using the
cgi_error() function. The error
messages are formatted as HTTP status codes. You can either incorporate the
error text into an HTML page, or use it as the value of the HTTP status:
my $error = $q->cgi_error;
if ($error) {
print $q->header(-status=>$error);
print "<H2>$error</H2>;
exit;
}
ACCESSOR METHODS¶
version() Get the CGI::Simple version info¶
$version = $q->version();
The
version() method returns the value of $VERSION
$q->nph(1); # enable NPH mode
$q->nph(0); # disable NPH mode
The
nph() method enables and disables NPH headers.
See the NPH section.
all_parameters() Get the names/values of all
parameters¶
@all_parameters = $q->all_parameters();
The
all_parameters() method is an alias for
param()
charset() Get/set the current character set.¶
$charset = $q->charset(); # get current charset
$q->charset('utf-42'); # set the charset
The
charset() method gets the current charset value
if no argument is supplied or sets it if an argument is supplied.
crlf() Get the system specific line ending sequence¶
$crlf = $q->crlf();
The
crlf() method returns the system specific line
ending sequence.
globals() Get/set the value of the remaining global
variables¶
$globals = $q->globals('FATAL'); # get the current value of $FATAL
$globals = $q->globals('FATAL', 1 ); # set croak mode on cgi_error()
The
globals() method gets/sets the values of the
global variables after the script has been invoked. For globals like $POST_MAX
and $DISABLE_UPLOADS this makes no difference as they must be set prior to
calling the new constructor but there might be reason the change the value of
others.
auth_type() Get the current authorization/verification
method¶
$auth_type = $q->auth_type();
The
auth_type() method returns the value of
$ENV{'AUTH_TYPE'} which should contain the authorization/verification method
in use for this script, if any.
content_length() Get the content length submitted in a
POST¶
$content_length = $q->content_length();
The
content_length() method returns the value of
$ENV{'AUTH_TYPE'}
content_type() Get the content_type of data submitted in a
POST¶
$content_type = $q->content_type();
The
content_type() method returns the content_type
of data submitted in a POST, generally 'multipart/form-data' or
'application/x-www-form-urlencoded' as supplied in $ENV{'CONTENT_TYPE'}
document_root() Get the document root¶
$document_root = $q->document_root();
The
document_root() method returns the value of
$ENV{'DOCUMENT_ROOT'}
gateway_interface() Get the gateway interface¶
$gateway_interface = $q->gateway_interface();
The
gateway_interface() method returns the value of
$ENV{'GATEWAY_INTERFACE'}
path_translated() Get the value of path translated¶
$path_translated = $q->path_translated();
The
path_translated() method returns the value of
$ENV{'PATH_TRANSLATED'}
referer() Spy on your users¶
$referer = $q->referer();
The
referer() method returns the value of
$ENV{'REFERER'} This will return the URL of the page the browser was viewing
prior to fetching your script. Not available for all browsers.
remote_addr() Get the remote address¶
$remote_addr = $q->remote_addr();
The
remote_addr() method returns the value of
$ENV{'REMOTE_ADDR'} or 127.0.0.1 (localhost) if this is not defined.
remote_host() Get a value for remote host¶
$remote_host = $q->remote_host();
The
remote_host() method returns the value of
$ENV{'REMOTE_HOST'} if it is defined. If this is not defined it returns
$ENV{'REMOTE_ADDR'} If this is not defined it returns 'localhost'
remote_ident() Get the remote identity¶
$remote_ident = $q->remote_ident();
The
remote_ident() method returns the value of
$ENV{'REMOTE_IDENT'}
remote_user() Get the remote user¶
$remote_user = $q->remote_user();
The
remote_user() method returns the
authorization/verification name used for user verification, if this script is
protected. The value comes from $ENV{'REMOTE_USER'}
request_method() Get the request method¶
$request_method = $q->request_method();
The
request_method() method returns the method used
to access your script, usually one of 'POST', 'GET' or 'HEAD' as supplied by
$ENV{'REQUEST_METHOD'}
script_name() Get the script name¶
$script_name = $q->script_name();
The
script_name() method returns the value of
$ENV{'SCRIPT_NAME'} if it is defined. Otherwise it returns Perl's script name
from $0. Failing this it returns a null string ''
server_name() Get the server name¶
$server_name = $q->server_name();
The
server_name() method returns the value of
$ENV{'SERVER_NAME'} if defined or 'localhost' otherwise
server_port() Get the port the server is listening on¶
$server_port = $q->server_port();
The
server_port() method returns the value
$ENV{'SERVER_PORT'} if defined or 80 if not.
server_protocol() Get the current server protocol¶
$server_protocol = $q->server_protocol();
The
server_protocol() method returns the value of
$ENV{'SERVER_PROTOCOL'} if defined or 'HTTP/1.0' otherwise
server_software() Get the server software¶
$server_software = $q->server_software();
The
server_software() method returns the value
$ENV{'SERVER_SOFTWARE'} or 'cmdline' If the server software is IIS it formats
your hard drive, installs Linux, FTPs to www.apache.org, installs Apache, and
then restores your system from tape. Well maybe not, but it's a nice thought.
user_name() Get a value for the user name.¶
$user_name = $q->user_name();
Attempt to obtain the remote user's name, using a variety of different
techniques. This only works with older browsers such as Mosaic. Newer browsers
do not report the user name for privacy reasons!
Technically the
user_name() method returns the value
of $ENV{'HTTP_FROM'} or failing that $ENV{'REMOTE_IDENT'} or as a last choice
$ENV{'REMOTE_USER'}
user_agent() Get the users browser type¶
$ua = $q->user_agent(); # return the user agent
$ok = $q->user_agent('mozilla'); # return true if user agent 'mozilla'
The
user_agent() method returns the value of
$ENV{'HTTP_USER_AGENT'} when called without an argument or true or false if
the $ENV{'HTTP_USER_AGENT'} matches the passed argument. The matching is case
insensitive and partial.
virtual_host() Get the virtual host¶
$virtual_host = $q->virtual_host();
The
virtual_host() method returns the value of
$ENV{'HTTP_HOST'} if defined or $ENV{'SERVER_NAME'} as a default. Port numbers
are removed.
$path_info = $q->path_info();
The
path_info() method returns additional path
information from the script URL. E.G. fetching
/cgi-bin/your_script/additional/stuff will result in $q->
path_info() returning "/additional/stuff".
NOTE: The Microsoft Internet Information Server is broken with respect to
additional path information. If you use the Perl DLL library, the IIS server
will attempt to execute the additional path information as a Perl script. If
you use the ordinary file associations mapping, the path information will be
present in the environment, but incorrect. The best thing to do is to avoid
using additional path information in CGI scripts destined for use with IIS.
Accept() Get the browser MIME types¶
$Accept = $q->Accept();
The
Accept() method returns a list of MIME types
that the remote browser accepts. If you give this method a single argument
corresponding to a MIME type, as in $q->Accept('text/html'), it will return
a floating point value corresponding to the browser's preference for this type
from 0.0 (don't want) to 1.0. Glob types (e.g. text/*) in the browser's accept
list are handled correctly.
accept() Alias for Accept()¶
$accept = $q->accept();
The
accept() Method is an alias for
Accept()
$http = $q->http();
Called with no arguments the
http() method returns
the list of HTTP or HTTPS environment variables, including such things as
HTTP_USER_AGENT, HTTP_ACCEPT_LANGUAGE, and HTTP_ACCEPT_CHARSET, corresponding
to the like-named HTTP header fields in the request. Called with the name of
an HTTP header field, returns its value. Capitalization and the use of hyphens
versus underscores are not significant.
For example, all three of these examples are equivalent:
$requested_language = $q->http('Accept-language');
$requested_language = $q->http('Accept_language');
$requested_language = $q->http('HTTP_ACCEPT_LANGUAGE');
$https = $q->https();
The
https() method is similar to the
http()
method except that when called without an argument it returns the value of
$ENV{'HTTPS'} which will be true if a HTTPS connection is in use and false
otherwise.
protocol() Get the current protocol¶
$protocol = $q->protocol();
The
protocol() method returns 'https' if a HTTPS
connection is in use or the
server_protocol()
minus version numbers ('http') otherwise.
$full_url = $q->url();
$full_url = $q->url(-full=>1);
$relative_url = $q->url(-relative=>1);
$absolute_url = $q->url(-absolute=>1);
$url_with_path = $q->url(-path_info=>1);
$url_with_path_and_query = $q->url(-path_info=>1,-query=>1);
$netloc = $q->url(-base => 1);
url() returns the script's URL in a variety of
formats. Called without any arguments, it returns the full form of the URL,
including host name and port number
http://your.host.com/path/to/script.cgi
You can modify this format with the following named arguments:
- -absolute
- If true, produce an absolute URL, e.g.
/path/to/script.cgi
- -relative
- Produce a relative URL. This is useful if you want to
reinvoke your script with different parameters. For example:
script.cgi
- -full
- Produce the full URL, exactly as if called without any
arguments. This overrides the -relative and -absolute arguments.
- -path (-path_info)
- Append the additional path information to the URL. This can
be combined with -full, -absolute or -relative.
-path_info is provided as a synonym.
- -query (-query_string)
- Append the query string to the URL. This can be combined
with -full, -absolute or -relative.
-query_string is provided as a synonym.
- -base
- Generate just the protocol and net location, as in
http://www.foo.com:8000
self_url() Get the scripts complete URL¶
$self_url = $q->self_url();
The
self_url() method returns the value of:
$self->url( '-path_info'=>1, '-query'=>1, '-full'=>1 );
state() Alias for self_url()¶
$state = $q->state();
The
state() method is an alias for
self_url()
COMPATIBILITY WITH cgi-lib.pl 2.18¶
To make it easier to port existing programs that use cgi-lib.pl all the subs
within cgi-lib.pl are available in CGI::Simple. Using the functional interface
of CGI::Simple::Standard porting is as easy as:
OLD VERSION
require "cgi-lib.pl";
&ReadParse;
print "The value of the antique is $in{'antique'}.\n";
NEW VERSION
use CGI::Simple::Standard qw(:cgi-lib);
&ReadParse;
print "The value of the antique is $in{'antique'}.\n";
CGI:Simple's
ReadParse() routine creates a variable
named %in, which can be accessed to obtain the query variables. Like
ReadParse, you can also provide your own variable via a glob. Infrequently
used features of
ReadParse(), such as the creation
of @in and $in variables, are not supported.
You can also use the OO interface of CGI::Simple and call
ReadParse() and other cgi-lib.pl functions like
this:
&CGI::Simple::ReadParse; # get hash values in %in
my $q = new CGI::Simple;
$q->ReadParse(); # same thing
CGI::Simple::ReadParse(*field); # get hash values in %field function style
my $q = new CGI::Simple;
$q->ReadParse(*field); # same thing
Once you use
ReadParse() under the functional
interface , you can retrieve the query object itself this way if needed:
$q = $in{'CGI'};
Either way it allows you to start using the more interesting features of CGI.pm
without rewriting your old scripts from scratch.
Unlike CGI.pm all the cgi-lib.pl functions from Version 2.18 are supported:
ReadParse()
SplitParam()
MethGet()
MethPost()
MyBaseUrl()
MyURL()
MyFullUrl()
PrintHeader()
HtmlTop()
HtmlBot()
PrintVariables()
PrintEnv()
CgiDie()
CgiError()
COMPATIBILITY WITH CGI.pm¶
I has long been suggested that the CGI and HTML parts of CGI.pm should be split
into separate modules (even the author suggests this!), CGI::Simple represents
the realization of this and contains the complete CGI side of CGI.pm.
Code-wise it weighs in at a little under 30% of the size of CGI.pm at a little
under 1000 lines.
A great deal of care has been taken to ensure that the interface remains
unchanged although a few tweaks have been made. The test suite is extensive
and includes all the CGI.pm test scripts as well as a series of new test
scripts. You may like to have a look at /t/concur.t which makes 160 tests of
CGI::Simple and CGI in parallel and compares the results to ensure they are
identical. This is the case as of CGI.pm 2.78.
You can't make an omelet without breaking eggs. A large number of methods and
global variables have been deleted as detailed below. Some pragmas are also
gone. In the tarball there is a script
/misc/check.pl that will check
if a script seems to be using any of these now non existent methods, globals
or pragmas. You call it like this:
perl check.pl <files>
If it finds any likely candidates it will print a line with the line number,
problem method/global and the complete line. For example here is some output
from running the script on CGI.pm:
...
3162: Problem:'$CGI::OS' local($CRLF) = "\015\012" if $CGI::OS eq 'VMS';
3165: Problem:'fillBuffer' $self->fillBuffer($FILLUNIT);
....
DIFFERENCES FROM CGI.pm¶
CGI::Simple is strict and warnings compliant.
There are 4 modules in this distribution:
CGI/Simple.pm supplies all the core code.
CGI/Simple/Cookie.pm supplies the cookie handling functions.
CGI/Simple/Util.pm supplies a variety of utility functions
CGI/Simple/Standard.pm supplies a functional interface for Simple.pm
Simple.pm is the core module that provide all the essential functionality.
Cookie.pm is a shortened rehash of the CGI.pm module of the same name which
supplies the required cookie functionality. Util.pm has been recoded to use an
internal object for data storage and supplies rarely needed non core functions
and/or functions needed for the HTML side of things. Standard.pm is a wrapper
module that supplies a complete functional interface to the OO back end
supplied by CGI::Simple.
Although a serious attempt has been made to keep the interface identical, some
minor changes and tweaks have been made. They will likely be insignificant to
most users but here are the gory details.
Globals Variables¶
The list of global variables has been pruned by 75%. Here is the complete list
of the global variables used:
$VERSION = "0.01";
# set this to 1 to use CGI.pm default global settings
$USE_CGI_PM_DEFAULTS = 0 unless defined $USE_CGI_PM_DEFAULTS;
# see if user wants old CGI.pm defaults
do{ _use_cgi_pm_global_settings(); return } if $USE_CGI_PM_DEFAULTS;
# no file uploads by default, set to 0 to enable uploads
$DISABLE_UPLOADS = 1 unless defined $DISABLE_UPLOADS;
# use a post max of 100K, set to -1 for no limits
$POST_MAX = 102_400 unless defined $POST_MAX;
# do not include undefined params parsed from query string
$NO_UNDEF_PARAMS = 0 unless defined $NO_UNDEF_PARAMS;
# separate the name=value pairs with ; rather than &
$USE_PARAM_SEMICOLONS = 0 unless defined $USE_PARAM_SEMICOLONS;
# only print headers once
$HEADERS_ONCE = 0 unless defined $HEADERS_ONCE;
# Set this to 1 to enable NPH scripts
$NPH = 0 unless defined $NPH;
# 0 => no debug, 1 => from @ARGV, 2 => from STDIN
$DEBUG = 0 unless defined $DEBUG;
# filter out null bytes in param - value pairs
$NO_NULL = 1 unless defined $NO_NULL;
# set behavior when cgi_err() called -1 => silent, 0 => carp, 1 => croak
$FATAL = -1 unless defined $FATAL;
Four of the default values of the old CGI.pm variables have been changed. Unlike
CGI.pm which by default allows unlimited POST data and file uploads by default
CGI::Simple limits POST data size to 100kB and denies file uploads by default.
$USE_PARAM_SEMICOLONS is set to 0 by default so we use (old style) &
rather than ; as the pair separator for query strings. Debugging is disabled
by default.
There are three new global variables. If $NO_NULL is true (the default) then
CGI::Simple will strip null bytes out of names, values and keywords. Null
bytes can do interesting things to C based code like Perl. Uploaded files are
not touched. $FATAL controls the behavior when
cgi_error() is called. The default value of -1
makes errors silent. $USE_CGI_PM_DEFAULTS reverts the defaults to the CGI.pm
standard values ie unlimited file uploads via POST for DNS attacks. You can
also get the defaults back by using the '-default' pragma in the use:
use CGI::Simple qw(-default);
use CGI::Simple::Standard qw(-default);
The values of the global variables are stored in the CGI::Simple object and can
be referenced and changed using the
globals()
method like this:
my $value = $q->globals( 'VARNAME' ); # get
$q->globals( 'VARNAME', 'some value' ); # set
As with many CGI.pm methods if you pass the optional value that will be set.
The $CGI::Simple::VARNAME = 'N' syntax is only useful prior to calling the
new() constructor. After that all reference is to
the values stored in the CGI::Simple object so you must change these using the
globals() method.
$DISABLE_UPLOADS and $POST_MAX *must* be set prior to calling the constructor if
you want the changes to have any effect as they control behavior during
initialization. This is the same a CGI.pm although some people seem to miss
this rather important point and set these after calling the constructor which
does nothing.
The following globals are no longer relevant and have all been deleted:
$AUTOLOADED_ROUTINES
$AUTOLOAD_DEBUG
$BEEN_THERE
$CRLF
$DEFAULT_DTD
$EBCDIC
$FH
$FILLUNIT
$IIS
$IN
$INITIAL_FILLUNIT
$JSCRIPT
$MAC
$MAXTRIES
$MOD_PERL
$NOSTICKY
$OS
$PERLEX
$PRIVATE_TEMPFILES
$Q
$QUERY_CHARSET
$QUERY_PARAM
$SCRATCH
$SL
$SPIN_LOOP_MAX
$TIMEOUT
$TMPDIRECTORY
$XHTML
%EXPORT
%EXPORT_OK
%EXPORT_TAGS
%OVERLOAD
%QUERY_FIELDNAMES
%SUBS
@QUERY_PARAM
@TEMP
Notes: CGI::Simple uses IO::File->new_tmpfile to get tempfile filehandles.
These are private by default so $PRIVATE_TEMPFILES is no longer required nor
is $TMPDIRECTORY. The value that were stored in $OS, $CRLF, $QUERY_CHARSET and
$EBCDIC are now stored in the CGI::Simple::Util object where they find most of
their use. The $MOD_PERL and $PERLEX values are now stored in our CGI::Simple
object. $IIS was only used once in
path_info(). $SL the system specific
/ \ : path delimiter is not required as we let IO::File handle our tempfile
requirements. The rest of the globals are HTML related, export related, hand
rolled autoload related or serve obscure purposes in CGI.pm
Changes to pragmas¶
There are some new pragmas available. See the pragmas section for details. The
following CGI.pm pragmas are not available:
-any
-compile
-nosticky
-no_xhtml
-private_tempfiles
Filehandles¶
Unlike CGI.pm which tries to accept all filehandle like objects only \*FH and
$fh are accepted by CGI::Simple as file accessors for
new() and
save().
IO::File objects work fine.
Hash interface¶
%hash = $q->Vars(); # pack values with "\0";
%hash = $q->Vars(","); # comma separate values
You may optionally pass
Vars() a string that will be
used to separate multiple values when they are packed into the single hash
value. If no value is supplied the default "\0" (null byte) will be
used. Null bytes are dangerous things for C based code (ie Perl).
cgi-lib.pl¶
All the cgi-lib.pl 2.18 routines are supported. Unlike CGI.pm all the
subroutines from cgi-lib.pl are included. They have been GOLFED down to 25
lines but they all work pretty much the same as the originals.
CGI::Simple COMPLETE METHOD LIST¶
Here is a complete list of all the CGI::Simple methods.
Guts (hands off, except of course for new)¶
_initialize_globals
_use_cgi_pm_global_settings
_store_globals
import
_reset_globals
new
_initialize
_read_parse
_parse_params
_add_param
_parse_keywordlist
_parse_multipart
_save_tmpfile
_read_data
Core Methods¶
param
add_param
param_fetch
url_param
keywords
Vars
append
delete
Delete
delete_all
Delete_all
upload
upload_info
query_string
parse_query_string
parse_keywordlist
Save and Restore from File Methods¶
_init_from_file
save
save_parameters
Miscellaneous Methods¶
url_decode
url_encode
escapeHTML
unescapeHTML
put
print
Cookie Methods¶
cookie
raw_cookie
header
cache
no_cache
redirect
Server Push Methods¶
multipart_init
multipart_start
multipart_end
multipart_final
Debugging Methods¶
read_from_cmdline
Dump
as_string
cgi_error
cgi-lib.pl Compatibility Routines - all 2.18 functions
available¶
_shift_if_ref
ReadParse
SplitParam
MethGet
MethPost
MyBaseUrl
MyURL
MyFullUrl
PrintHeader
HtmlTop
HtmlBot
PrintVariables
PrintEnv
CgiDie
CgiError
Accessor Methods¶
version
nph
all_parameters
charset
crlf # new, returns OS specific CRLF sequence
globals # get/set global variables
auth_type
content_length
content_type
document_root
gateway_interface
path_translated
referer
remote_addr
remote_host
remote_ident
remote_user
request_method
script_name
server_name
server_port
server_protocol
server_software
user_name
user_agent
virtual_host
path_info
Accept
accept
http
https
protocol
url
self_url
state
NEW METHODS IN CGI::Simple¶
There are a few new methods in CGI::Simple as listed below. The highlights are
the
parse_query_string() method to add the
QUERY_STRING data to your object if the method was POST. The
no_cache() method adds an expires now directive
and the Pragma: no-cache directive to the header to encourage some browsers to
do the right thing.
PrintEnv() from the cgi-lib.pl
routines will dump an HTML friendly list of the %ENV and makes a handy
addition to
Dump() for use in debugging. The
upload method now accepts a filepath as an optional second argument as shown
in the synopsis. If this is supplied the uploaded file will be written to
there automagically.
Internal Routines¶
_initialize_globals()
_use_cgi_pm_global_settings()
_store_globals()
_initialize()
_init_from_file()
_read_parse()
_parse_params()
_add_param()
_parse_keywordlist()
_parse_multipart()
_save_tmpfile()
_read_data()
New Public Methods¶
add_param() # adds a param/value(s) pair +/- overwrite
upload_info() # uploaded files MIME type and size
url_decode() # decode s url encoded string
url_encode() # url encode a string
parse_query_string() # add QUERY_STRING data to $q object if 'POST'
no_cache() # add both the Pragma: no-cache
# and Expires/Date => 'now' to header
cgi-lib.pl methods added for completeness¶
_shift_if_ref() # internal hack reminiscent of self_or_default :-)
MyBaseUrl()
MyURL()
MyFullUrl()
PrintVariables()
PrintEnv()
CgiDie()
CgiError()
New Accessors¶
crlf() # returns CRLF sequence
globals() # global vars now stored in $q object - get/set
content_length() # returns $ENV{'CONTENT_LENGTH'}
document_root() # returns $ENV{'DOCUMENT_ROOT'}
gateway_interface() # returns $ENV{'GATEWAY_INTERFACE'}
METHODS IN CGI.pm NOT IN CGI::Simple¶
Here is a complete list of what is not included in CGI::Simple. Basically all
the HTML related stuff plus large redundant chunks of the guts. The check.pl
script in the /misc dir will check to see if a script is using any of these.
Guts - rearranged, recoded, renamed and hacked out of
existence¶
initialize_globals()
compile()
expand_tags()
self_or_default()
self_or_CGI()
init()
to_filehandle()
save_request()
parse_params()
add_parameter()
binmode()
_make_tag_func()
AUTOLOAD()
_compile()
_setup_symbols()
new_MultipartBuffer()
read_from_client()
import_names() # I dislike this and left it out, so shoot me.
autoEscape()
URL_ENCODED()
MULTIPART()
SERVER_PUSH()
start_html()
_style()
_script()
end_html()
isindex()
startform()
start_form()
end_multipart_form()
start_multipart_form()
endform()
end_form()
_textfield()
textfield()
filefield()
password_field()
textarea()
button()
submit()
reset()
defaults()
comment()
checkbox()
checkbox_group()
_tableize()
radio_group()
popup_menu()
scrolling_list()
hidden()
image_button()
nosticky()
default_dtd()
CGI::Simple uses anonymous tempfiles supplied by IO::File to spool uploaded
files to.
private_tempfiles() # automatic in CGI::Simple
tmpFileName() # all upload files are anonymous
uploadInfo() # relied on FH access, replaced with upload_info()
Really Private Subs (marked as so)¶
previous_or_default()
register_parameter()
get_fields()
_set_values_and_labels()
_compile_all()
asString()
compare()
Internal Multipart Parsing Routines¶
read_multipart()
readHeader()
readBody()
read()
fillBuffer()
eof()
EXPORT¶
Nothing.
Originally copyright 2001 Dr James Freeman <jfreeman@tassie.net.au> This
release by Andy Armstrong <andy@hexten.net>
This package is free software and is provided "as is" without express
or implied warranty. It may be used, redistributed and/or modified under the
terms of the Perl Artistic License (see
http://www.perl.com/perl/misc/Artistic.html)
Address bug reports and comments to: andy@hexten.net. When sending bug reports,
please provide the version of CGI::Simple, the version of Perl, the name and
version of your Web server, and the name and version of the operating system
you are using. If the problem is even remotely browser dependent, please
provide information about the affected browsers as well.
Address bug reports and comments to: andy@hexten.net
CREDITS¶
Lincoln D. Stein (lstein@cshl.org) and everyone else who worked on the original
CGI.pm upon which this module is heavily based
Brandon Black for some heavy duty testing and bug fixes
John D Robinson and Jeroen Latour for helping solve some interesting test
failures as well as Perlmonks: tommyw, grinder, Jaap, vek, erasei, jlongino
and strider_corinth
Thanks for patches to:
Ewan Edwards, Joshua N Pritikin, Mike Barry, Michael Nachbaur, Chris Williams,
Mark Stosberg, Krasimir Berov, Yamada Masahiro
LICENCE AND COPYRIGHT¶
Copyright (c) 2007, Andy Armstrong "<andy@hexten.net>". All
rights reserved.
This module is free software; you can redistribute it and/or modify it under the
same terms as Perl itself. See perlartistic.
SEE ALSO¶
CGI, CGI::Simple::Standard, CGI::Simple::Cookie, CGI::Simple::Util,
CGI::Minimal
