Library 5.1 Release Notes

If you are reading the text version of this document then you can find a HTML version in

	Library/User/ReleaseNotes.html

The main features in this release are:

• Full HTTP/1.1 sample implementation
• Advanced use of HTTP/1.1 Pipelining and persistent connections
• Persistent cache manager

The focus for version 5.1 was to implement a high-performance HTTP/1.1 client used as a testbed for the "Network Performance Effects of HTTP/1.1, CSS1, and PNG" paper. Note that this code is sample code so please take it as that and nothing more!

Check out the latest  WWW APIs and  a complete list of public functions

Release 5.1m (to be released)

These are the things that are upcoming in the next release

New Features

• Made sure that we write more often as we check for expired timers in HTWriter.c
• Added a "repetitive" flag to timers so that they can be created to say call me every 30ms over and over again
• Added support for building libwww as a shared library on Unix (it is already using DLLs on Windows). If you have any problems with shared libraries on your platform then run configure with the --disable-shared flag and you will only get the static version. If you are using libwww as a shared library but do not use the libwww HTML parser then you MUST include this dummy implementation of the HText interface somewhere in your code. The reason for this is that the HText interface may be called (it depends a bit on how your platform supports shared libraries) but an implementation isn't provided.
• Added support for MySQL access in this simple SQL interface which takes care of most os the common problems encountered when talking to an SQL server. Currently I use this for handling logging in the webbot but many other features like persistent caching, preferences, etc. can use the SQL module as well. You can also see some cool examples of how to use the robot's logs when querying MySQL through www-sql.
• Changed the name of "config.h" to "wwwconf.h" as the first name caused conflicts with other packages
• Changed the name of "sysdep.h" to "wwwsys.h" for the same reason

Bug Fixes

• Fixed a bug in the generation of relative URIs which caused the creation of incorrecte relative URIs. Libwww uses relative URIs in the HTTP referer field and other places to save (often significant) amount of bandwidth.
• Decreased mdefault max number of outstanding (pipelined) requests from 100 to 50
• Does now check whether we get a broken pipe when writing to the network from expired timers. This was a bug that it didn't.
• Applied the following patches
• Fixed a problem in the HTWWWStr.c that caused a Y2K bug if strftime isn't available on the system on where libwww is running

Release 5.1l March 25, 1998

This is a small add-on to 5.1k that was released two days ago. It has a few fixes that was discovered while working with the latest Arena browser.

Bug Fixes

• Minor stuff that made PUT work nicer from a user perspective (when to ask what questions, etc)
• Fixed a few things in the direct WAIS access module

Release 5.1k March 23, 1998

New Features

• Added a simple "single user lock" on the persistent cache as it gets confused if multiple users are using it.
• On Unic, the header files are now installed when running "make install". The default location is "/usr/local/include/w3c-libwww".
• On Unix, aset of icons that can be used when browsing local file directories are also installed - the default location is "/usr/local/share/w3c-libwww"

Bug Fixes

• These are the patches that I have recieved for the current release. They will be applied to this upcoming release.
• Fixed a few bugs that make Arena run on top of the latest version

Release 5.1j March 9, 1998

New Features

• Made the distinction between Transfer-Encoding and Content-Transfer-Encoding clear - they were somewhat mixed up before. Libwww also now supports multiple transfer-codings as well as multiple content-codings as required by HTTP/1.1.
• Changed the Stream Stack to not call the SaveLocally stream any more but instead return an ErrorStream. The reason for this is that there are several places in the stram stack building algorithm where we might want to save the file to local file: when there is a content type that we don't understand, a content-encoding, or a transfer-encoding (or a combiunation of these) that we don't understand. Now we can make sure that the SaveLocally stream is only called once
• Added support for "identity" transfer-coding and content-coding
• Added support for Allow header when doing PUT and POST

Bug Fixes

• Fixed a problem handling wrong HTTP responses from NCSA HTTPD dereived servers (they don't include a version number when responding to an HTTP/1.1 request)
• PUT now works much more reliable, and it also works on Windows (at least  NT, I haven't tested it on 95).
• Fixed a refresh problem in the Line Mode Browser which caused it to sometimes render the screen twice.

Release 5.1f January 1998

New Features

• Changed the referer HTTP header field to use relative URIs instead of absolute. This saves a lot of bytes on the wire
• Added support for logging the charset media type parameter
• Added support for logging when the ALT tag is missing from inlined images
• Extended the log class to support arbitrary log files

Bug Fixes

• Fixed some problems in the HTRelative function in HTParse.

Release 5.1e January 1998

New Features

• Added support for linking against a POSIX Regular Expression (regex) library. This is used in the Robot, for example, to support regular expressions on URIs to include and exclude from a traversal. The code has been tested with the GNU regex library.
• Added more logging features to the webbot

Bug Fixes

• Fixed bug in ouputstream that caused buffer to be overwritten in some cases when blocked on write

Release 5.1d December 1997

Bug Fixes

• Lots of bug fixes in the pipelining code and increased performance

New Features

• Better logging facilities with support for multiple log objects including referer logging, Common Log File format logging and general logging filters.

Release 5.1c September 1997

• Lots of bug fixes

Release 5.1b April 1997

Bug Fixes

• Fixed a problem in HTRules.c as described in this bug report
• Fixed coredump problem in HTGetTmpFileName() as described in this bug report. This affects also the HTCache module which relies on temporary file names
• Made the persistent cache more robust which in some cases will save a segmentation fault
• Fixed problem in wwwsys.h as reported in this bug report
• Fixed problem where a request was not flushed if using blocking sockets as reported by this bug report.
• A limitation in the current persistent cache is that it only works in non-preemptive mode. Hence if using blocking sockets then the cache should be disabled. This is now the default behavior in the libwww profiles.
• Bug fixed that caused the maxsock variable used in select() not to be decreased when deleting a socket in the default event manager
• Changed the connection management so that it complies with the Connection Management draft by Jim Gettys and Alan Freier. The HTTP client now closes idle connections after 60 seconds which is a heuristic period chosen by Jeff Mogul in the paper "The Case for Persistent-Connection HTTP". The number can be dynamically changed using the HTHost_setPersistTimeout() and the HTHost_persistTimeout() methods. This could be made more advanced so that we take into account any information given in the "Keep-Alive" header but isn't for now.
• Fixed a problem when a HTTP/1.1 server sent a response including a Connection: close header using the close of the TCP connection as a delimiter. This problem was pointed out in this bug report
• Fixed security hole handling HTTP 305 proxy redirection codes. The proxy location returned in the responses was enabled as a permanent proxy without any notification. The operation now requires explicit acknowledgement from the user
• Fixed potential (but small) security whole handling parsing a new rules file. This operation now requires explicit acknowledgement from the user.

Release 5.1 February 18 1997

New Features and APIs

• Added support  pipelining
• Support for zlib based decompression in content encoding

Bug Fixes

• A whole bunch of them...