[Tcl-bugs] [ tcl-Bugs-3165982 ] http 2.7 dependency on zlib breaks in Tcl 8.5

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Bugs item #3165982, was opened at 2011-01-26 15:51
Message generated for change (Settings changed) made by patthoyts
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Category: 29. http Package
Group: current: 8.5.9
>Status: Closed
>Resolution: Wont Fix
Priority: 5
Private: No
Submitted By: Azazel (a3a3el)
Assigned to: Pat Thoyts (patthoyts)
Summary: http 2.7 dependency on zlib breaks in Tcl 8.5

Initial Comment:
The http 2.7 package introduced in 8.5.2 has a dependency on the in-core zlib
package which is only present in 8.6.  Consequently, any gzip-encoded response
is incorrectly handled.

Here I use 8.5.1:

  $ cat <<END | /tmp/tcl8.5.1/bin/tclsh8.5
  > puts "Tcl: [package present Tcl]"
  > package require http
  > puts "HTTP: [package present http]"
  > if { [ catch {
  >   set tok [http::geturl http://centrebet.com/cust \
  >     -headers {Accept-Encoding gzip}]
  > } err] } {
  >   puts \$err
  > } else {
  >   puts \$tok
  > }
  > END
  Tcl: 8.5.1
  HTTP: 2.5.3
  ::http::1

which doesn't attempt the decompress the body, and http::geturl returns
successfully.

Here I use 8.5.2:

  $ cat <<END | /tmp/tcl8.5.2/bin/tclsh8.5
  > puts "Tcl: [package present Tcl]"
  > package require http
  > puts "HTTP: [package present http]"
  > if { [ catch {
  >   set tok [http::geturl http://centrebet.com/cust \
  >     -headers {Accept-Encoding gzip}]
  > } err] } {
  >   puts \$err
  > } else {
  >   puts \$tok
  > }
  > END
  Tcl: 8.5.2
  HTTP: 2.7
  invalid command name "zlib"

which calls http::Gunzip to decompress and fails because zlib is not available.


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>Comment By: Pat Thoyts (patthoyts)
Date: 2011-01-27 13:27

Message:
This feature is to enable support of compressed streams when you have a
supported zip extension. There is one built into tcl 8.6 but in 8.5 people
can load one in and one is included in tclkit.
If - and only if - a suitable extension package was loaded the http
package will include the Accept-Encoding header to indicate that it can
support compressed streams. You have deliberately set this header to
indicate you will accept gzip compressed data. In this case you are
responsible for decoding it. If you plan on using a different incompatible
package to decompress the data then you can replace the Gunzip function
with your own once you load the http package. Beware that the http package
uses lazy loading so you should actually call the http::geturl function to
force loading the procedures before you replace them.
 

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