path: root/library/http/http.tcl

# http.tcl --
#
#	Client-side HTTP for GET, POST, and HEAD commands. These routines can
#	be used in untrusted code that uses the Safesock security policy. These
#	procedures use a callback interface to avoid using vwait, which is not
#	defined in the safe base.
#
# See the file "license.terms" for information on usage and redistribution of
# this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# RCS: @(#) $Id: http.tcl,v 1.65 2008/03/12 05:57:44 hobbs Exp $

# Rough version history:
# 1.0	Old http_get interface.
# 2.0	http:: namespace and http::geturl.
# 2.1	Added callbacks to handle arriving data, and timeouts.
# 2.2	Added ability to fetch into a channel.
# 2.3	Added SSL support, and ability to post from a channel. This version
#	also cleans up error cases and eliminates the "ioerror" status in
#	favor of raising an error
# 2.4	Added -binary option to http::geturl and charset element to the state
#	array.

package require Tcl 8.4
# Keep this in sync with pkgIndex.tcl and with the install directories
# in Makefiles
package provide http 2.5.5

namespace eval http {
    # Allow resourcing to not clobber existing data

    variable http
    if {![info exists http]} {
	array set http {
	    -accept */*
	    -proxyhost {}
	    -proxyport {}
	    -proxyfilter http::ProxyRequired
	    -urlencoding utf-8
	}
	set http(-useragent) "Tcl http client package [package provide http]"
    }

    proc init {} {
	# Set up the map for quoting chars. RFC3986 Section 2.3 say percent
	# encode all except: "... percent-encoded octets in the ranges of ALPHA
	# (%41-%5A and %61-%7A), DIGIT (%30-%39), hyphen (%2D), period (%2E),
	# underscore (%5F), or tilde (%7E) should not be created by URI
	# producers ..."
	for {set i 0} {$i <= 256} {incr i} {
	    set c [format %c $i]
	    if {![string match {[-._~a-zA-Z0-9]} $c]} {
		set map($c) %[format %.2x $i]
	    }
	}
	# These are handled specially
	set map(\n) %0d%0a
	variable formMap [array get map]
    }
    init

    variable urlTypes
    if {![info exists urlTypes]} {
	set urlTypes(http) [list 80 ::socket]
    }

    variable encodings [string tolower [encoding names]]
    # This can be changed, but iso8859-1 is the RFC standard.
    variable defaultCharset "iso8859-1"

    # Force RFC 3986 strictness in geturl url verification?
    variable strict 1

    namespace export geturl config reset wait formatQuery register unregister
    # Useful, but not exported: data size status code
}

# http::register --
#
#     See documentation for details.
#
# Arguments:
#     proto           URL protocol prefix, e.g. https
#     port            Default port for protocol
#     command         Command to use to create socket
# Results:
#     list of port and command that was registered.

proc http::register {proto port command} {
    variable urlTypes
    set urlTypes($proto) [list $port $command]
}

# http::unregister --
#
#     Unregisters URL protocol handler
#
# Arguments:
#     proto           URL protocol prefix, e.g. https
# Results:
#     list of port and command that was unregistered.

proc http::unregister {proto} {
    variable urlTypes
    if {![info exists urlTypes($proto)]} {
	return -code error "unsupported url type \"$proto\""
    }
    set old $urlTypes($proto)
    unset urlTypes($proto)
    return $old
}

# http::config --
#
#	See documentation for details.
#
# Arguments:
#	args		Options parsed by the procedure.
# Results:
#        TODO

proc http::config {args} {
    variable http
    set options [lsort [array names http -*]]
    set usage [join $options ", "]
    if {[llength $args] == 0} {
	set result {}
	foreach name $options {
	    lappend result $name $http($name)
	}
	return $result
    }
    set options [string map {- ""} $options]
    set pat ^-([join $options |])$
    if {[llength $args] == 1} {
	set flag [lindex $args 0]
	if {[regexp -- $pat $flag]} {
	    return $http($flag)
	} else {
	    return -code error "Unknown option $flag, must be: $usage"
	}
    } else {
	foreach {flag value} $args {
	    if {[regexp -- $pat $flag]} {
		set http($flag) $value
	    } else {
		return -code error "Unknown option $flag, must be: $usage"
	    }
	}
    }
}

# http::Finish --
#
#	Clean up the socket and eval close time callbacks
#
# Arguments:
#	token	    Connection token.
#	errormsg    (optional) If set, forces status to error.
#       skipCB      (optional) If set, don't call the -command callback. This
#                   is useful when geturl wants to throw an exception instead
#                   of calling the callback. That way, the same error isn't
#                   reported to two places.
#
# Side Effects:
#        Closes the socket

proc http::Finish { token {errormsg ""} {skipCB 0}} {
    variable $token
    upvar 0 $token state
    global errorInfo errorCode
    if {$errormsg ne ""} {
	set state(error) [list $errormsg $errorInfo $errorCode]
	set state(status) "error"
    }
    catch {close $state(sock)}
    if {[info exists state(after)]} { after cancel $state(after) }
    if {[info exists state(-command)] && !$skipCB} {
	if {[catch {eval $state(-command) {$token}} err]} {
	    if {$errormsg eq ""} {
		set state(error) [list $err $errorInfo $errorCode]
		set state(status) error
	    }
	}
	# Command callback may already have unset our state
	unset -nocomplain state(-command)
    }
}

# http::reset --
#
#	See documentation for details.
#
# Arguments:
#	token	Connection token.
#	why	Status info.
#
# Side Effects:
#       See Finish

proc http::reset { token {why reset} } {
    variable $token
    upvar 0 $token state
    set state(status) $why
    catch {fileevent $state(sock) readable {}}
    catch {fileevent $state(sock) writable {}}
    Finish $token
    if {[info exists state(error)]} {
	set errorlist $state(error)
	unset state
	eval ::error $errorlist
    }
}

# http::geturl --
#
#	Establishes a connection to a remote url via http.
#
# Arguments:
#       url		The http URL to goget.
#       args		Option value pairs. Valid options include:
#				-blocksize, -validate, -headers, -timeout
# Results:
#	Returns a token for this connection. This token is the name of an array
#	that the caller should unset to garbage collect the state.

proc http::geturl { url args } {
    variable http
    variable urlTypes
    variable defaultCharset
    variable strict

    # Initialize the state variable, an array. We'll return the name of this
    # array as the token for the transaction.

    if {![info exists http(uid)]} {
	set http(uid) 0
    }
    set token [namespace current]::[incr http(uid)]
    variable $token
    upvar 0 $token state
    reset $token

    # Process command options.

    array set state {
	-binary		false
	-blocksize	8192
	-queryblocksize 8192
	-validate	0
	-headers	{}
	-timeout	0
	-type		application/x-www-form-urlencoded
	-queryprogress	{}
	state		header
	meta		{}
	coding		{}
	currentsize	0
	totalsize	0
	querylength	0
	queryoffset	0
	type		text/html
	body		{}
	status		""
	http		""
    }
    # These flags have their types verified [Bug 811170]
    array set type {
	-binary		boolean
	-blocksize	integer
	-queryblocksize integer
	-validate	boolean
	-timeout	integer
    }
    set state(charset)	$defaultCharset
    set options {
	-binary -blocksize -channel -command -handler -headers
	-method -progress -query -queryblocksize
	-querychannel -queryprogress -validate -timeout -type
    }
    set usage [join $options ", "]
    set options [string map {- ""} $options]
    set pat ^-([join $options |])$
    foreach {flag value} $args {
	if {[regexp $pat $flag]} {
	    # Validate numbers
	    if {[info exists type($flag)] && \
		    ![string is $type($flag) -strict $value]} {
		unset $token
		return -code error "Bad value for $flag ($value), must be $type($flag)"
	    }
	    set state($flag) $value
	} else {
	    unset $token
	    return -code error "Unknown option $flag, can be: $usage"
	}
    }

    # Make sure -query and -querychannel aren't both specified

    set isQueryChannel [info exists state(-querychannel)]
    set isQuery [info exists state(-query)]
    if {$isQuery && $isQueryChannel} {
	unset $token
	return -code error "Can't combine -query and -querychannel options!"
    }

    # Validate URL, determine the server host and port, and check proxy case
    # Recognize user:pass@host URLs also, although we do not do anything with
    # that info yet.

    # URLs have basically four parts.
    # First, before the colon, is the protocol scheme (e.g. http)
    # Second, for HTTP-like protocols, is the authority
    #	The authority is preceded by // and lasts up to (but not including)
    #	the following / and it identifies up to four parts, of which only one,
    #	the host, is required (if an authority is present at all). All other
    #	parts of the authority (user name, password, port number) are optional.
    # Third is the resource name, which is split into two parts at a ?
    #	The first part (from the single "/" up to "?") is the path, and the
    #	second part (from that "?" up to "#") is the query. *HOWEVER*, we do
    #	not need to separate them; we send the whole lot to the server.
    # Fourth is the fragment identifier, which is everything after the first
    #	"#" in the URL. The fragment identifier MUST NOT be sent to the server
    #	and indeed, we don't bother to validate it (it could be an error to
    #	pass it in here, but it's cheap to strip).
    #
    # An example of a URL that has all the parts:
    #   http://jschmoe:xyzzy@www.bogus.net:8000/foo/bar.tml?q=foo#changes
    # The "http" is the protocol, the user is "jschmoe", the password is
    # "xyzzy", the host is "www.bogus.net", the port is "8000", the path is
    # "/foo/bar.tml", the query is "q=foo", and the fragment is "changes".
    #
    # Note that the RE actually combines the user and password parts, as
    # recommended in RFC 3986. Indeed, that RFC states that putting passwords
    # in URLs is a Really Bad Idea, something with which I would agree utterly.
    # Also note that we do not currently support IPv6 addresses.
    #
    # From a validation perspective, we need to ensure that the parts of the
    # URL that are going to the server are correctly encoded.
    # This is only done if $::http::strict is true (default 0 for compat).

    set URLmatcher {(?x)		# this is _expanded_ syntax
	^
	(?: (\w+) : ) ?			# <protocol scheme>
	(?: //
	    (?:
		(
		    [^@/\#?]+		# <userinfo part of authority>
		) @
	    )?
	    ( [^/:\#?]+ )		# <host part of authority>
	    (?: : (\d+) )?		# <port part of authority>
	)?
	( / [^\#?]* (?: \? [^\#?]* )?)?	# <path> (including query)
	(?: \# (.*) )?			# <fragment>
	$
    }

    # Phase one: parse
    if {![regexp -- $URLmatcher $url -> proto user host port srvurl]} {
	unset $token
	return -code error "Unsupported URL: $url"
    }
    # Phase two: validate
    if {$host eq ""} {
	# Caller has to provide a host name; we do not have a "default host"
	# that would enable us to handle relative URLs.
	unset $token
	return -code error "Missing host part: $url"
	# Note that we don't check the hostname for validity here; if it's
	# invalid, we'll simply fail to resolve it later on.
    }
    if {$port ne "" && $port > 65535} {
	unset $token
	return -code error "Invalid port number: $port"
    }
    # The user identification and resource identification parts of the URL can
    # have encoded characters in them; take care!
    if {$user ne ""} {
	# Check for validity according to RFC 3986, Appendix A
	set validityRE {(?xi)
	    ^
	    (?: [-\w.~!$&'()*+,;=:] | %[0-9a-f][0-9a-f] )+
	    $
	}
	if {$strict && ![regexp -- $validityRE $user]} {
	    unset $token
	    # Provide a better error message in this error case
	    if {[regexp {(?i)%(?![0-9a-f][0-9a-f]).?.?} $user bad]} {
		return -code error \
			"Illegal encoding character usage \"$bad\" in URL user"
	    }
	    return -code error "Illegal characters in URL user"
	}
    }
    if {$srvurl ne ""} {
	# Check for validity according to RFC 3986, Appendix A
	set validityRE {(?xi)
	    ^
	    # Path part (already must start with / character)
	    (?:	      [-\w.~!$&'()*+,;=:@/]  | %[0-9a-f][0-9a-f] )*
	    # Query part (optional, permits ? characters)
	    (?: \? (?: [-\w.~!$&'()*+,;=:@/?] | %[0-9a-f][0-9a-f] )* )?
	    $
	}
	if {$strict && ![regexp -- $validityRE $srvurl]} {
	    unset $token
	    # Provide a better error message in this error case
	    if {[regexp {(?i)%(?![0-9a-f][0-9a-f])..} $srvurl bad]} {
		return -code error \
			"Illegal encoding character usage \"$bad\" in URL path"
	    }
	    return -code error "Illegal characters in URL path"
	}
    } else {
	set srvurl /
    }
    if {[string length $proto] == 0} {
	set proto http
    }
    if {![info exists urlTypes($proto)]} {
	unset $token
	return -code error "Unsupported URL type \"$proto\""
    }
    set defport [lindex $urlTypes($proto) 0]
    set defcmd [lindex $urlTypes($proto) 1]

    if {[string length $port] == 0} {
	set port $defport
    }
    if {![catch {$http(-proxyfilter) $host} proxy]} {
	set phost [lindex $proxy 0]
	set pport [lindex $proxy 1]
    }

    # OK, now reassemble into a full URL
    set url ${proto}://
    if {$user ne ""} {
	append url $user
	append url @
    }
    append url $host
    if {$port != $defport} {
	append url : $port
    }
    append url $srvurl
    # Don't append the fragment!
    set state(url) $url

    # If a timeout is specified we set up the after event and arrange for an
    # asynchronous socket connection.

    if {$state(-timeout) > 0} {
	set state(after) [after $state(-timeout) \
		[list http::reset $token timeout]]
	set async -async
    } else {
	set async ""
    }

    # If we are using the proxy, we must pass in the full URL that includes
    # the server name.

    if {[info exists phost] && [string length $phost]} {
	set srvurl $url
	set conStat [catch {eval $defcmd $async {$phost $pport}} s]
    } else {
	set conStat [catch {eval $defcmd $async {$host $port}} s]
    }

    if {$conStat} {
	# Something went wrong while trying to establish the connection. Clean
	# up after events and such, but DON'T call the command callback (if
	# available) because we're going to throw an exception from here
	# instead.
	Finish $token "" 1
	cleanup $token
	return -code error $s
    }
    set state(sock) $s

    # Wait for the connection to complete.

    if {$state(-timeout) > 0} {
	fileevent $s writable [list http::Connect $token]
	http::wait $token

	if {![info exists state]} {
	    # If we timed out then Finish has been called and the users
	    # command callback may have cleaned up the token. If so
	    # we end up here with nothing left to do.
	    return $token
	} elseif {$state(status) eq "error"} {
	    # Something went wrong while trying to establish the connection.
	    # Clean up after events and such, but DON'T call the command
	    # callback (if available) because we're going to throw an
	    # exception from here instead.
	    set err [lindex $state(error) 0]
	    cleanup $token
	    return -code error $err
	} elseif {$state(status) ne "connect"} {
	    # Likely to be connection timeout
	    return $token
	}
	set state(status) ""
    }

    # Send data in cr-lf format, but accept any line terminators

    fconfigure $s -translation {auto crlf} -buffersize $state(-blocksize)

    # The following is disallowed in safe interpreters, but the socket is
    # already in non-blocking mode in that case.

    catch {fconfigure $s -blocking off}
    set how GET
    if {$isQuery} {
	set state(querylength) [string length $state(-query)]
	if {$state(querylength) > 0} {
	    set how POST
	    set contDone 0
	} else {
	    # There's no query data.
	    unset state(-query)
	    set isQuery 0
	}
    } elseif {$state(-validate)} {
	set how HEAD
    } elseif {$isQueryChannel} {
	set how POST
	# The query channel must be blocking for the async Write to
	# work properly.
	fconfigure $state(-querychannel) -blocking 1 -translation binary
	set contDone 0
    }
    if {[info exists state(-method)] && $state(-method) ne ""} {
	set how $state(-method)
    }

    if {[catch {
	puts $s "$how $srvurl HTTP/1.0"
	puts $s "Accept: $http(-accept)"
	if {$port == $defport} {
	    # Don't add port in this case, to handle broken servers. [Bug
	    # 504508]
	    puts $s "Host: $host"
	} else {
	    puts $s "Host: $host:$port"
	}
	puts $s "User-Agent: $http(-useragent)"
	foreach {key value} $state(-headers) {
	    set value [string map [list \n "" \r ""] $value]
	    set key [string trim $key]
	    if {$key eq "Content-Length"} {
		set contDone 1
		set state(querylength) $value
	    }
	    if {[string length $key]} {
		puts $s "$key: $value"
	    }
	}
	if {$isQueryChannel && $state(querylength) == 0} {
	    # Try to determine size of data in channel. If we cannot seek, the
	    # surrounding catch will trap us

	    set start [tell $state(-querychannel)]
	    seek $state(-querychannel) 0 end
	    set state(querylength) \
		    [expr {[tell $state(-querychannel)] - $start}]
	    seek $state(-querychannel) $start
	}

	# Flush the request header and set up the fileevent that will either
	# push the POST data or read the response.
	#
	# fileevent note:
	#
	# It is possible to have both the read and write fileevents active at
	# this point. The only scenario it seems to affect is a server that
	# closes the connection without reading the POST data. (e.g., early
	# versions TclHttpd in various error cases). Depending on the platform,
	# the client may or may not be able to get the response from the server
	# because of the error it will get trying to write the post data.
	# Having both fileevents active changes the timing and the behavior,
	# but no two platforms (among Solaris, Linux, and NT) behave the same,
	# and none behave all that well in any case. Servers should always read
	# their POST data if they expect the client to read their response.

	if {$isQuery || $isQueryChannel} {
	    puts $s "Content-Type: $state(-type)"
	    if {!$contDone} {
		puts $s "Content-Length: $state(querylength)"
	    }
	    puts $s ""
	    fconfigure $s -translation {auto binary}
	    fileevent $s writable [list http::Write $token]
	} else {
	    puts $s ""
	    flush $s
	    fileevent $s readable [list http::Event $token]
	}

	if {! [info exists state(-command)]} {
	    # geturl does EVERYTHING asynchronously, so if the user calls it
	    # synchronously, we just do a wait here.

	    wait $token
	    if {$state(status) eq "error"} {
		# Something went wrong, so throw the exception, and the
		# enclosing catch will do cleanup.
		return -code error [lindex $state(error) 0]
	    }
	}
    } err]} {
	# The socket probably was never connected, or the connection dropped
	# later.

	# Clean up after events and such, but DON'T call the command callback
	# (if available) because we're going to throw an exception from here
	# instead.

	# if state(status) is error, it means someone's already called Finish
	# to do the above-described clean up.
	if {$state(status) ne "error"} {
	    Finish $token $err 1
	}
	cleanup $token
	return -code error $err
    }

    return $token
}

# Data access functions:
# Data - the URL data
# Status - the transaction status: ok, reset, eof, timeout
# Code - the HTTP transaction code, e.g., 200
# Size - the size of the URL data

proc http::data {token} {
    variable $token
    upvar 0 $token state
    return $state(body)
}
proc http::status {token} {
    if {![info exists $token]} { return "error" }
    variable $token
    upvar 0 $token state
    return $state(status)
}
proc http::code {token} {
    variable $token
    upvar 0 $token state
    return $state(http)
}
proc http::ncode {token} {
    variable $token
    upvar 0 $token state
    if {[regexp {[0-9]{3}} $state(http) numeric_code]} {
	return $numeric_code
    } else {
	return $state(http)
    }
}
proc http::size {token} {
    variable $token
    upvar 0 $token state
    return $state(currentsize)
}
proc http::meta {token} {
    variable $token
    upvar 0 $token state
    return $state(meta)
}
proc http::error {token} {
    variable $token
    upvar 0 $token state
    if {[info exists state(error)]} {
	return $state(error)
    }
    return ""
}

# http::cleanup
#
#	Garbage collect the state associated with a transaction
#
# Arguments
#	token	The token returned from http::geturl
#
# Side Effects
#	unsets the state array

proc http::cleanup {token} {
    variable $token
    upvar 0 $token state
    if {[info exists state]} {
	unset state
    }
}

# http::Connect
#
#	This callback is made when an asyncronous connection completes.
#
# Arguments
#	token	The token returned from http::geturl
#
# Side Effects
#	Sets the status of the connection, which unblocks
# 	the waiting geturl call

proc http::Connect {token} {
    variable $token
    upvar 0 $token state
    global errorInfo errorCode
    if {[eof $state(sock)] ||
	[string length [fconfigure $state(sock) -error]]} {
	    Finish $token "connect failed [fconfigure $state(sock) -error]" 1
    } else {
	set state(status) connect
	fileevent $state(sock) writable {}
    }
    return
}

# http::Write
#
#	Write POST query data to the socket
#
# Arguments
#	token	The token for the connection
#
# Side Effects
#	Write the socket and handle callbacks.

proc http::Write {token} {
    variable $token
    upvar 0 $token state
    set s $state(sock)

    # Output a block.  Tcl will buffer this if the socket blocks
    set done 0
    if {[catch {
	# Catch I/O errors on dead sockets

	if {[info exists state(-query)]} {
	    # Chop up large query strings so queryprogress callback can give
	    # smooth feedback.

	    puts -nonewline $s \
		[string range $state(-query) $state(queryoffset) \
		     [expr {$state(queryoffset) + $state(-queryblocksize) - 1}]]
	    incr state(queryoffset) $state(-queryblocksize)
	    if {$state(queryoffset) >= $state(querylength)} {
		set state(queryoffset) $state(querylength)
		set done 1
	    }
	} else {
	    # Copy blocks from the query channel

	    set outStr [read $state(-querychannel) $state(-queryblocksize)]
	    puts -nonewline $s $outStr
	    incr state(queryoffset) [string length $outStr]
	    if {[eof $state(-querychannel)]} {
		set done 1
	    }
	}
    } err]} {
	# Do not call Finish here, but instead let the read half of the socket
	# process whatever server reply there is to get.

	set state(posterror) $err
	set done 1
    }
    if {$done} {
	catch {flush $s}
	fileevent $s writable {}
	fileevent $s readable [list http::Event $token]
    }

    # Callback to the client after we've completely handled everything.

    if {[string length $state(-queryprogress)]} {
	eval $state(-queryprogress) \
	    [list $token $state(querylength) $state(queryoffset)]
    }
}

# http::Event
#
#	Handle input on the socket
#
# Arguments
#	token	The token returned from http::geturl
#
# Side Effects
#	Read the socket and handle callbacks.

proc http::Event {token} {
    variable $token
    upvar 0 $token state
    set s $state(sock)

    if {$state(state) eq "header"} {
	if {[catch {gets $s line} n]} {
	    return [Finish $token $n]
	} elseif {$n == 0} {
	    variable encodings
	    set state(state) body
	    if {$state(-binary) || ![string match -nocase text* $state(type)]
		    || [string match *gzip* $state(coding)]
		    || [string match *compress* $state(coding)]} {
		# Turn off conversions for non-text data
		fconfigure $s -translation binary
		if {[info exists state(-channel)]} {
		    fconfigure $state(-channel) -translation binary
		}
	    } else {
		# If we are getting text, set the incoming channel's encoding
		# correctly. iso8859-1 is the RFC default, but this could be
		# any IANA charset. However, we only know how to convert what
		# we have encodings for.
		set idx [lsearch -exact $encodings \
			[string tolower $state(charset)]]
		if {$idx >= 0} {
		    fconfigure $s -encoding [lindex $encodings $idx]
		}
	    }
	    if {[info exists state(-channel)] && \
		    ![info exists state(-handler)]} {
		# Initiate a sequence of background fcopies
		fileevent $s readable {}
		CopyStart $s $token
		return
	    }
	} elseif {$n > 0} {
	    if {[regexp -nocase {^content-type:(.+)$} $line x type]} {
		set state(type) [string trim $type]
		# grab the optional charset information
		regexp -nocase {charset\s*=\s*(\S+)} $type x state(charset)
	    }
	    if {[regexp -nocase {^content-length:(.+)$} $line x length]} {
		set state(totalsize) [string trim $length]
	    }
	    if {[regexp -nocase {^content-encoding:(.+)$} $line x coding]} {
		set state(coding) [string trim $coding]
	    }
	    if {[regexp -nocase {^([^:]+):(.+)$} $line x key value]} {
		lappend state(meta) $key [string trim $value]
	    } elseif {[string match HTTP* $line]} {
		set state(http) $line
	    }
	}
    } else {
	if {[catch {
	    if {[info exists state(-handler)]} {
		set n [eval $state(-handler) {$s $token}]
	    } else {
		set block [read $s $state(-blocksize)]
		set n [string length $block]
		if {$n >= 0} {
		    append state(body) $block
		}
	    }
	    if {$n >= 0} {
		incr state(currentsize) $n
	    }
	} err]} {
	    return [Finish $token $err]
	} else {
	    if {[info exists state(-progress)]} {
		eval $state(-progress) \
		    [list $token $state(totalsize) $state(currentsize)]
	    }
	}
    }

    if {[eof $s]} {
	Eof $token
	return
    }
}

# http::CopyStart
#
#	Error handling wrapper around fcopy
#
# Arguments
#	s	The socket to copy from
#	token	The token returned from http::geturl
#
# Side Effects
#	This closes the connection upon error

proc http::CopyStart {s token} {
    variable $token
    upvar 0 $token state
    if {[catch {
	fcopy $s $state(-channel) -size $state(-blocksize) -command \
	    [list http::CopyDone $token]
    } err]} {
	Finish $token $err
    }
}

# http::CopyDone
#
#	fcopy completion callback
#
# Arguments
#	token	The token returned from http::geturl
#	count	The amount transfered
#
# Side Effects
#	Invokes callbacks

proc http::CopyDone {token count {error {}}} {
    variable $token
    upvar 0 $token state
    set s $state(sock)
    incr state(currentsize) $count
    if {[info exists state(-progress)]} {
	eval $state(-progress) \
	    [list $token $state(totalsize) $state(currentsize)]
    }
    # At this point the token may have been reset
    if {[string length $error]} {
	Finish $token $error
    } elseif {[catch {eof $s} iseof] || $iseof} {
	Eof $token
    } else {
	CopyStart $s $token
    }
}

# http::Eof
#
#	Handle eof on the socket
#
# Arguments
#	token	The token returned from http::geturl
#
# Side Effects
#	Clean up the socket

proc http::Eof {token} {
    variable $token
    upvar 0 $token state
    if {$state(state) eq "header"} {
	# Premature eof
	set state(status) eof
    } else {
	set state(status) ok
    }
    set state(state) eof
    Finish $token
}

# http::wait --
#
#	See documentation for details.
#
# Arguments:
#	token	Connection token.
#
# Results:
#        The status after the wait.

proc http::wait {token} {
    variable $token
    upvar 0 $token state

    if {![info exists state(status)] || [string length $state(status)] == 0} {
	# We must wait on the original variable name, not the upvar alias
	vwait ${token}(status)
    }

    return [status $token]
}

# http::formatQuery --
#
#	See documentation for details. Call http::formatQuery with an even
#	number of arguments, where the first is a name, the second is a value,
#	the third is another name, and so on.
#
# Arguments:
#	args	A list of name-value pairs.
#
# Results:
#	TODO

proc http::formatQuery {args} {
    set result ""
    set sep ""
    foreach i $args {
	append result $sep [mapReply $i]
	if {$sep eq "="} {
	    set sep &
	} else {
	    set sep =
	}
    }
    return $result
}

# http::mapReply --
#
#	Do x-www-urlencoded character mapping
#
# Arguments:
#	string	The string the needs to be encoded
#
# Results:
#       The encoded string

proc http::mapReply {string} {
    variable http
    variable formMap

    # The spec says: "non-alphanumeric characters are replaced by '%HH'". Use
    # a pre-computed map and [string map] to do the conversion (much faster
    # than [regsub]/[subst]). [Bug 1020491]

    if {$http(-urlencoding) ne ""} {
	set string [encoding convertto $http(-urlencoding) $string]
	return [string map $formMap $string]
    }
    set converted [string map $formMap $string]
    if {[string match "*\[\u0100-\uffff\]*" $converted]} {
	regexp {[\u0100-\uffff]} $converted badChar
	# Return this error message for maximum compatability... :^/
	return -code error \
	    "can't read \"formMap($badChar)\": no such element in array"
    }
    return $converted
}

# http::ProxyRequired --
#	Default proxy filter.
#
# Arguments:
#	host	The destination host
#
# Results:
#       The current proxy settings

proc http::ProxyRequired {host} {
    variable http
    if {[info exists http(-proxyhost)] && [string length $http(-proxyhost)]} {
	if {![info exists http(-proxyport)] || \
		![string length $http(-proxyport)]} {
	    set http(-proxyport) 8080
	}
	return [list $http(-proxyhost) $http(-proxyport)]
    }
}

# Local variables:
# indent-tabs-mode: t
# End: