###############################################################################
#
# common.tcl --
#
# Extensible Adaptable Generalized Logic Engine (Eagle)
# Eagle Common Tools Package
#
# Copyright (c) 2007-2012 by Joe Mistachkin. All rights reserved.
#
# See the file "license.terms" for information on usage and redistribution of
# this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# RCS: @(#) $Id: $
#
###############################################################################
#
# NOTE: This script file uses features that are only present in Tcl 8.4 or
# higher (e.g. the "eq" operator for [expr], etc).
#
if {![package vsatisfies [package provide Tcl] 8.4]} then {
error "need Tcl 8.4 or higher"
}
#
# NOTE: This script file uses features that are not available or not needed
# in Eagle (e.g. the "http" and "tls" packages, etc).
#
if {[catch {package present Eagle}] == 0} then {
error "need native Tcl"
}
###############################################################################
namespace eval ::Eagle::Tools::Common {
#
# NOTE: *HACK* Skip defining this procedure if it is already defined in the
# global namespace.
#
if {[llength [info commands ::appendArgs]] == 0} then {
#
# NOTE: This procedure was stolen from the "auxiliary.eagle" script.
# This procedure accepts an any number of arguments. The arguments
# are appended into one big string, verbatim. The resulting string
# is returned. Normally, this procedure is used to avoid undesired
# string interpolation operations.
#
proc appendArgs { args } {
eval append result $args
}
}
#
# NOTE: *HACK* Skip defining this procedure if it is already defined in the
# global namespace.
#
if {[llength [info commands ::makeBinaryChannel]] == 0} then {
#
# NOTE: This procedure was stolen from the "file1.eagle" script. This
# procedure reconfigures the specified channel to full binary mode.
#
proc makeBinaryChannel { channel } {
fconfigure $channel -encoding binary -translation binary; # BINARY DATA
}
}
#
# NOTE: *HACK* Skip defining this procedure if it is already defined in the
# global namespace.
#
if {[llength [info commands ::writeFile]] == 0} then {
#
# NOTE: This procedure was stolen from the "file1.eagle" script. This
# procedure writes all data to the specified binary file and returns
# an empty string. Previous data contained in the file, if any, is
# lost.
#
proc writeFile { fileName data } {
set channel [open $fileName {WRONLY CREAT TRUNC}]
makeBinaryChannel $channel
puts -nonewline $channel $data
close $channel
return ""
}
}
#
# NOTE: This procedure was stolen from the "getEagle.tcl" script. This
# procedure sets up the default values for all HTTP configuration
# parameters used by this package. If the force argument is
# non-zero, any existing values will be overwritten and set back
# to their default values.
#
proc setupCommonVariables { force } {
#
# NOTE: Should the HTTP request processor attempt to force the use of
# HTTPS for URIs that were originally HTTP? This setting is only
# applicable to native Tcl.
#
variable forceSecureUri; # DEFAULT: true
if {$force || ![info exists forceSecureUri]} then {
set forceSecureUri true
}
#
# NOTE: Is this HTTP request processor allowed to use plain HTTP if/when
# the "tls" package is not available? This should only be changed
# if the "tls" package cannot be easily installed for use with the
# native Tcl interpreter in use. It should be noted here that the
# official package repository server reserves the right to refuse
# plain HTTP connections, which means that changing this setting
# may be totally pointless.
#
variable allowInsecureUri; # DEFAULT: false
if {$force || ![info exists allowInsecureUri]} then {
set allowInsecureUri false
}
#
# NOTE: Emit diagnostic messages when the [::http::geturl] procedure is
# about to be called?
#
variable verboseGetUrl; # DEFAULT: false
if {$force || ![info exists verboseGetUrl]} then {
set verboseGetUrl false
}
#
# NOTE: Is this HTTP request processor allowed to use plain HTTP if/when
# the server responds with an HTTP redirect location to an original
# URI that was HTTPS? Otherwise, a script error will result.
#
variable allowInsecureRedirect; # DEFAULT: false
if {![info exists allowInsecureRedirect]} then {
set allowInsecureRedirect false
}
}
#
# NOTE: This procedure was stolen from the "getEagle.tcl" script. It is
# designed to emit a message to the console. The channel argument
# is the channel where the message should be written. The string
# argument is the content of the message to emit. If the channel
# argument is an empty string, nothing is written.
#
proc pageOut { channel string } {
if {[string length $channel] > 0} then {
catch {
puts -nonewline $channel $string; flush $channel
}
}
}
#
# NOTE: This procedure was stolen from the "getEagle.tcl" script. It is
# designed to emit a message to the HTTP client log. The string
# argument is the content of the message to emit. If the string
# argument is an empty string, nothing is written.
#
proc pageLog { string } {
if {[string length $string] > 0} then {
catch {
tclLog [appendArgs \
[pid] " : " [clock seconds] " : http : " $string]
}
}
}
#
# NOTE: This procedure was stolen from the "getEagle.tcl" script. It is
# designed to emit a progress indicator while an HTTP request is
# being processed. The channel argument is the Tcl channel where
# the progress indicator should be emitted. The type argument is
# the single-character progress indicator. The milliseconds
# argument is the number of milliseconds to wait until the next
# periodic progress indicator should be emitted. This procedure
# reschedules its own execution.
#
proc pageProgress { channel type milliseconds } {
#
# NOTE: This variable is used to keep track of the currently scheduled
# (i.e. pending) [after] event.
#
variable afterForPageProgress
#
# NOTE: Show that something is happening...
#
pageOut $channel $type
#
# NOTE: Make sure that we are scheduled to run again, if requested.
#
if {$milliseconds > 0} then {
set afterForPageProgress [after $milliseconds \
[namespace code [list pageProgress $channel $type \
$milliseconds]]]
} else {
unset -nocomplain afterForPageProgress
}
}
#
# NOTE: This procedure was stolen from the "getEagle.tcl" script. It is
# designed to process a single HTTP request, including any HTTP
# 3XX redirects (up to the specified limit), and return the raw
# HTTP response data. It may raise any number of script errors.
#
proc getFileViaHttp { uri redirectLimit channel quiet args } {
#
# NOTE: This global variable is used to check the running version of
# Tcl.
#
global tcl_version
#
# NOTE: This variable is used to determine if plain HTTP URIs should be
# converted to HTTPS, if the "tls" package is available.
#
variable forceSecureUri
#
# NOTE: This variable is used to determine if plain HTTP is allowed if
# the "tls" package is not available.
#
variable allowInsecureUri
#
# NOTE: This variable is used to determine if a diagnostic message is
# emitted when [::http::geturl] is about to be called.
#
variable verboseGetUrl
#
# NOTE: This variable is used to determine if plain HTTP is allowed if
# an HTTP redirect response contains an HTTP URI and the original
# URI was HTTPS.
#
variable allowInsecureRedirect
#
# NOTE: This variable is used to keep track of the currently scheduled
# (i.e. pending) [after] event.
#
variable afterForPageProgress
#
# NOTE: This procedure requires the modern version of the HTTP package,
# which is typically included with the Tcl core distribution.
#
package require http 2.0
#
# NOTE: Tcl 8.6 added support for IPv6; however, on some machines this
# support can cause sockets to hang for a long time. Therefore,
# for now, always force the use of IPv4.
#
if {[info exists tcl_version] && $tcl_version >= 8.6} then {
namespace eval ::tcl::unsupported {}
set ::tcl::unsupported::socketAF inet
}
#
# NOTE: If the 'tls' package is available, always attempt to use HTTPS;
# otherwise, only attempt to use HTTP if explicitly allowed.
#
if {[catch {package require tls}] == 0} then {
::http::register https 443 [list ::tls::socket -tls1 true]
if {$forceSecureUri} then {
if {[string range $uri 0 6] eq "http://"} then {
set uri [appendArgs https:// [string range $uri 7 end]]
}
}
} else {
if {$allowInsecureUri} then {
if {[string range $uri 0 7] eq "https://"} then {
set uri [appendArgs http:// [string range $uri 8 end]]
}
}
}
#
# NOTE: Unless the caller forbids it, display progress messages during
# the download.
#
if {!$quiet} then {
pageProgress $channel . 250
}
#
# NOTE: All downloads are handled synchronously, which is not ideal;
# however, it is simple. Keep going as long as there are less
# than X redirects.
#
set redirectCount 0
while {1} {
#
# NOTE: Issue the HTTP request now, grabbing the resulting token.
#
if {$verboseGetUrl} then {
#
# NOTE: Emit important diagnostic information related to this
# HTTP request here. This may be enhanced in the future.
#
pageLog [appendArgs \
"attempting to download URL \"" $uri \"...]
}
set token [eval ::http::geturl [list $uri] $args]
#
# NOTE: Grab the HTTP response code and data now as they are needed
# in almost all cases.
#
set code [::http::ncode $token]; set data [::http::data $token]
#
# NOTE: If the HTTP response code is an empty string that may
# indicate a serious bug in the tls (or http) package for
# this platform. So far, this issue has only been seen
# with the tls 1.6.1 package that shipped with macOS.
#
if {[string length $code] == 0} then {
error [appendArgs \
"received empty HTTP response code for URL \"" $uri \
"\", the \"tls\" (and/or \"http\") package(s) may be " \
"broken for this platform"]
}
#
# NOTE: Check the HTTP response code, in order to follow any HTTP
# redirect responses.
#
switch -glob -- $code {
100 -
101 -
102 {
::http::cleanup $token; error [appendArgs \
"unsupported informational HTTP response status code " \
$code ", data: " $data]
}
200 -
201 -
202 -
203 -
204 -
205 -
206 -
207 -
208 -
226 {
#
# NOTE: Ok, the HTTP response is actual data of some kind (which
# may be empty).
#
::http::cleanup $token; break
}
301 -
302 -
303 -
307 -
308 {
#
# NOTE: Unless the caller forbids it, display progress messages
# when an HTTP redirect is returned.
#
if {!$quiet} then {
pageProgress $channel > 0
}
#
# NOTE: We hit another HTTP redirect. Stop if there are more
# than X.
#
incr redirectCount
#
# TODO: Maybe make this limit more configurable?
#
if {$redirectCount > $redirectLimit} then {
#
# NOTE: Just "give up" and raise a script error.
#
::http::cleanup $token; error [appendArgs \
"redirection limit of " $redirectLimit " exceeded"]
}
#
# NOTE: Grab the metadata associated with this HTTP response.
#
array set meta [::http::meta $token]
#
# NOTE: Is there actually a new URI (location) to use?
#
if {[info exist meta(Location)]} then {
#
# NOTE: Ok, grab it now. Later, at the top of the loop,
# it will be used in the subsequent HTTP request.
#
set location $meta(Location); unset meta
#
# NOTE: For security, by default, do NOT follow an HTTP
# redirect if it attempts to redirect from HTTPS
# to HTTP.
#
if {!$allowInsecureRedirect && \
[string range $uri 0 7] eq "https://" && \
[string range $location 0 7] ne "https://"} then {
#
# NOTE: Just "give up" and raise a script error.
#
::http::cleanup $token; error [appendArgs \
"refused insecure redirect from \"" $uri "\" to \"" \
$location \"]
}
#
# NOTE: Replace the original URI with the new one, for
# use in the next HTTP request.
#
set uri $location
#
# NOTE: Cleanup the current HTTP token now beause a new
# one will be created for the next request.
#
::http::cleanup $token
} else {
#
# NOTE: Just "give up" and raise a script error.
#
::http::cleanup $token; error [appendArgs \
"redirect from \"" $uri "\" missing location, code " \
$code ", data: " $data]
}
}
300 -
304 -
305 -
306 {
::http::cleanup $token; error [appendArgs \
"unsupported redirection HTTP response status code " $code \
", data: " $data]
}
4?? {
::http::cleanup $token; error [appendArgs \
"client error HTTP response status code " $code ", data: " \
$data]
}
5?? {
::http::cleanup $token; error [appendArgs \
"server error HTTP response status code " $code ", data: " \
$data]
}
default {
::http::cleanup $token; error [appendArgs \
"unrecognized HTTP response status code " $code ", data: " \
$data]
}
}
}
#
# NOTE: If there is a currently scheduled [after] event, cancel it.
#
if {[info exists afterForPageProgress]} then {
catch {after cancel $afterForPageProgress}
unset -nocomplain afterForPageProgress
}
#
# NOTE: If progress messages were emitted, start a fresh line.
#
if {!$quiet} then {
pageOut $channel [appendArgs " " $uri \n]
}
return $data
}
#
# NOTE: First, setup the variables associated with this package.
#
setupCommonVariables false
#
# NOTE: Export the procedures from this namespace that are designed to be
# used by external scripts.
#
namespace export appendArgs getFileViaHttp pageOut writeFile
#
# NOTE: Provide the package to the interpreter.
#
package provide Eagle.Tools.Common 1.0
}