http.tcl

Swarm,由圣塔菲研究所开发,用于复杂适应系统(CAS)仿真及其他

	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 {[string equal $state(status) "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 {[string equal $state(status) "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} {
    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::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 {[eof $s]} {
	Eof $token
	return
    }
    if {[string equal $state(state) "header"]} {
	if {[catch {gets $s line} n]} {
	    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 $token
	    }
	} elseif {$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]} {
	    Finish $token $err
	} else {
	    if {[info exists state(-progress)]} {
		eval $state(-progress) \
			{$token $state(totalsize) $state(currentsize)}
	    }
	}
    }
}

# 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 $state(-progress) {$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 {[string equal $state(state) "header"]} {
	# Premature eof
	set state(status) eof
    } else {
	set state(status) ok
    }
    set state(state) eof
    Finish $token
}

# http::wait --
#
#	See documentaion 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 $state(status)
}

# http::formatQuery --
#
#	See documentaion 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 {[string equal $sep "="]} {
	    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
    variable alphanumeric

    # The spec says: "non-alphanumeric characters are replaced by '%HH'"
    # 1 leave alphanumerics characters alone
    # 2 Convert every other character to an array lookup
    # 3 Escape constructs that are "special" to the tcl parser
    # 4 "subst" the result, doing all the array substitutions

    if {$http(-urlencoding) ne ""} {
	set string [encoding convertto $http(-urlencoding) $string]
    }
    regsub -all \[^$alphanumeric\] $string {$formMap(&)} string
    regsub -all {[][{})\\]\)} $string {\\&} string
    return [subst -nocommand $string]
}

# 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)]
    }
}