-accept mimetypes

The Accept header of the request. The default is */*, which means that all types of documents are accepted. Otherwise you can supply a comma-separated list of mime type patterns that you are willing to receive. For example, “image/gif, image/jpeg, text/*”.

-proxyhost hostname

The name of the proxy host, if any. If this value is the empty string, the URL host is contacted directly.

-proxyport number

The proxy port number.

-proxyfilter command

The command is a callback that is made during ::http::geturl to determine if a proxy is required for a given host. One argument, a host name, is added to command when it is invoked. If a proxy is required, the callback should return a two-element list containing the proxy server and proxy port. Otherwise the filter should return an empty list. The default filter returns the values of the -proxyhost and -proxyport settings if they are non-empty.

-urlencoding encoding

The encoding used for creating the x-url-encoded URLs with ::http::formatQuery. The default is utf-8, as specified by RFC 2718. Prior to http 2.5 this was unspecified, and that behavior can be returned by specifying the empty string ( {}), although iso8859-1 is recommended to restore similar behavior but without the ::http::formatQuery throwing an error processing non-latin-1 characters.

-useragent string

The value of the User-Agent header in the HTTP request. The default is “ Tcl http client package 2.7”.

-binary boolean

Specifies whether to force interpreting the URL data as binary. Normally this is auto-detected (anything not beginning with a text content type or whose content encoding is gzip or compress is considered binary data).

-blocksize size

The block size used when reading the URL. At most size bytes are read at once. After each block, a call to the -progress callback is made (if that option is specified).

-channel name

Copy the URL contents to channel name instead of saving it in state(body).

-command callback

Invoke callback after the HTTP transaction completes. This option causes ::http::geturl to return immediately. The callback gets an additional argument that is the token returned from ::http::geturl. This token is the name of an array that is described in the STATE ARRAY section. Here is a template for the callback:

proc httpCallback {token} {
    upvar #0 $token state
    # Access state as a Tcl array
}

-handler callback

Invoke callback whenever HTTP data is available; if present, nothing else will be done with the HTTP data. This procedure gets two additional arguments: the socket for the HTTP data and the token returned from ::http::geturl. The token is the name of a global array that is described in the STATE ARRAY section. The procedure is expected to return the number of bytes read from the socket. Here is a template for the callback:

proc httpHandlerCallback {socket token} {
    upvar #0 $token state
    # Access socket, and state as a Tcl array
    # For example...
    ...
    set data [read $socket 1000]
    set nbytes [string length $data]
    ...
    return $nbytes
}

-headers keyvaluelist

This option is used to add extra headers to the HTTP request. The keyvaluelist argument must be a list with an even number of elements that alternate between keys and values. The keys become header field names. Newlines are stripped from the values so the header cannot be corrupted. For example, if keyvaluelist is Pragma no-cache then the following header is included in the HTTP request:

Pragma: no-cache

-keepalive boolean

If true, attempt to keep the connection open for servicing multiple requests. Default is 0.

-method type

Force the HTTP request method to type. ::http::geturl will auto-select GET, POST or HEAD based on other options, but this option enables choices like PUT and DELETE for webdav support.

-myaddr address

Pass an specific local address to the underlying socket call in case multiple interfaces are available.

-progress callback

The callback is made after each transfer of data from the URL. The callback gets three additional arguments: the token from ::http::geturl, the expected total size of the contents from the Content-Length meta-data, and the current number of bytes transferred so far. The expected total size may be unknown, in which case zero is passed to the callback. Here is a template for the progress callback:

proc httpProgress {token total current} {
    upvar #0 $token state
}

-protocol version

Select the HTTP protocol version to use. This should be 1.0 or 1.1 (the default). Should only be necessary for servers that do not understand or otherwise complain about HTTP/1.1.

-query query

This flag causes ::http::geturl to do a POST request that passes the query to the server. The query must be an x-url-encoding formatted query. The ::http::formatQuery procedure can be used to do the formatting.

-queryblocksize size

The block size used when posting query data to the URL. At most size bytes are written at once. After each block, a call to the -queryprogress callback is made (if that option is specified).

-querychannel channelID

This flag causes ::http::geturl to do a POST request that passes the data contained in channelID to the server. The data contained in channelID must be an x-url-encoding formatted query unless the -type option below is used. If a Content-Length header is not specified via the -headers options, ::http::geturl attempts to determine the size of the post data in order to create that header. If it is unable to determine the size, it returns an error.

-queryprogress callback

The callback is made after each transfer of data to the URL (i.e. POST) and acts exactly like the -progress option (the callback format is the same).

-strict boolean

Whether to enforce RFC 3986 URL validation on the request. Default is 1.

-timeout milliseconds

If milliseconds is non-zero, then ::http::geturl sets up a timeout to occur after the specified number of milliseconds. A timeout results in a call to ::http::reset and to the -command callback, if specified. The return value of ::http::status is timeout after a timeout has occurred.

-type mime-type

Use mime-type as the Content-Type value, instead of the default value ( application/x-www-form-urlencoded) during a POST operation.

-validate boolean

If boolean is non-zero, then ::http::geturl does an HTTP HEAD request. This request returns meta information about the URL, but the contents are not returned. The meta information is available in the state(meta) variable after the transaction. See the STATE ARRAY section for details.

upvar #0 $token state

body

The contents of the URL. This will be empty if the -channel option has been specified. This value is returned by the ::http::data command.

charset

The value of the charset attribute from the Content-Type meta-data value. If none was specified, this defaults to the RFC standard iso8859-1, or the value of $::http::defaultCharset. Incoming text data will be automatically converted from this charset to utf-8.

coding

A copy of the Content-Encoding meta-data value.

currentsize

The current number of bytes fetched from the URL. This value is returned by the ::http::size command.

error

If defined, this is the error string seen when the HTTP transaction was aborted.

http

The HTTP status reply from the server. This value is returned by the ::http::code command. The format of this value is:

HTTP/1.1 code string

meta

The HTTP protocol returns meta-data that describes the URL contents. The meta element of the state array is a list of the keys and values of the meta-data. This is in a format useful for initializing an array that just contains the meta-data:

array set meta $state(meta)

posterror

The error, if any, that occurred while writing the post query data to the server.

status

Either ok, for successful completion, reset for user-reset, timeout if a timeout occurred before the transaction could complete, or error for an error condition. During the transaction this value is the empty string.

totalsize

A copy of the Content-Length meta-data value.

type

A copy of the Content-Type meta-data value.

url

The requested URL.

# Copy a URL to a file and print meta-data
proc httpcopy { url file {chunk 4096} } {
   set out [open $file w]
   set token [ ::http::geturl $url -channel $out \
          -progress httpCopyProgress -blocksize $chunk]
   close $out

   # This ends the line started by httpCopyProgress
   puts stderr ""

   upvar #0 $token state
   set max 0
   foreach {name value} $state(meta) {
      if {[string length $name] > $max} {
         set max [string length $name]
      }
      if {[regexp -nocase ^location$ $name]} {
         # Handle URL redirects
         puts stderr "Location:$value"
         return [httpcopy [string trim $value] $file $chunk]
      }
   }
   incr max
   foreach {name value} $state(meta) {
      puts [format "%-*s %s" $max $name: $value]
   }

   return $token
}
proc httpCopyProgress {args} {
   puts -nonewline stderr .
   flush stderr
}