# Library 4.1 Release Notes

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The focus for version 4.1 of the W3C Reference Library is to provide a set of higher level, application specific APIs for accessing the Web. These APIs - called profiles - will help the application, a Web client for example, to more easily use the full potential of the application independent Library core. Also, the Library contains a significantly better interface for easy access to the Web through a large set of functions specialized to perform certain Web operations like `PUT`, `POST`, `DELETE`, `GET` and `HEAD`.

Check out the latest list of public functions

## Release 4.1b4 August 20 1996

HTTP version 1.1 allows for effective use of persistent connections. However, in orderto make this work, a client application must be capable of recovering from a closed connection between sent requests. The beta 4 version of libwww supports automatic connection recovery and provides the functionality for performing pipelining of requests. That is, there can be multiple outstanding requests on the same connection In order to do this, the release contains modifications to the Channel Object, the Host object and the Net object.

### New Features

- Added support for case-insensitive searching for proxies via environment variables
- Added support for proxy authentication
- Changed handling of proxies so that they are not included in the URL (invented by Lou M) but is now instead part of the request object. This allows for better handling of proxies and also for more freely use of the proxy filter as it doesn't affect the other filters anymore.
- Added support for TRACE HTTP method in the HTAccess module.
- Updated News DLL and incorporated News patches from Maciej Puzio
- `HT_PERSISTENT` is now obsolete and should be replaced by `HT_PENDING`
- The `HTChannelMode` enumeration describing the flow of a channel has been replaced by `HTTransportMode` as it is now a part of the transport object and not the channel object
- `HTNet_idle()` has been removed and replaced by `HTNet_isIdle()`. The function returns YES if there are no pending requests in libwww at all.
- Add support for checking public information about a host and use this information when issuing a PUT, for example. Also add check for host element in HTAccess when doing PUT. We may have public information available
- Changed the return codes defined in HTUtils to reflect the values of the HTTP spec.
- Added support for `305 Use Proxy` redirections
- Updated HTDir module to better use the fact that we know that an entry is a directory or not. Now it appends a '/' to the URL if it is a directory. That way we often avoid a redirection.
- Removed WWWRules as interface and merged it with the WWWApp interface. The reason was that the two were highly alike and depended on each other

### Bug Fixes

- Fixed problem with uploading directory listing using chunked encoding
- Fixed autoconf to handle WAIS and updated the HTWAIS.c module
- Fixed race problem in PUT on alphas
- Tested reentrant version of libwww (uses `_REENTRANT` define)
- Fixed problem in file name conversion from URL to local format on Windows

## Release 4.1b3 July 20 1996

This release contains a TCL add-on to the Robot example application and a Deja GNU Test suite for the Library. Also, it support HTTP/1.1 including persistent connections, two-way `PUT`, and the `host` header. There is also a sample PEP implementation, that although incomplete can give an idea of where we're headed using PEP.

The file access module now does content negotiation by default. This means that all local file access (including from client applications) do content negotiation when accessing local files. Content negotiation can be turned off by setting a flag in the request object.

A main difference in beta 3 is that we now have a set of "application profiles" that helps the application to initialize libwww core to work as a typical client, robot or other type of application. This should replace the huge initialization procedure seen in previous versions. This is in fact a result of the core being so flexible - it is inly a framework for accessing the Web. The application must initialize all the functionality at run-time. You can see the various profile functions in the WWWInit interface.

The second main difference is that the BEFORE and AFTER filters have been more explicit than before. The `HTLoadStart` and `HTLoadTerminate` functions actually covered many typical BEFORE and AFTER filter functions like looking for proxies, searching the cache, looking for rule file matching, and logging etc.

However, two functions were not covered by this: redirection and authentication. That is why the application in previous version had to supply this functionality. However, in beta 3 we have split up the `HTLoadStart` and `HTLoadTerminte` functions into a set of filters which each perform only a single function, for example looking for proxies. The split has two functions: first it shows how you can use filtes to add new functionality to the Library and second it can be used by more types of applications. A result of the new filters is that we also have default redirection and authentication filters so you don't have to provide this anymore.

The filters are set up as part of the profiles so you will normally not have to register them individually.

### New features and Changes

- Introduced HTUserprofile class to handle host and user specific information
- Added Chunked decoding and encoding module
- A host name is not expanded to a fqdn name as it is not reliable enough. Now we just keep it as is, that is we don't expand www to www.w3.org, for example.
- Updated HTML parser to support `BASE` tag and `LINK` tag
- Added new access methods to the HTAccess module. It is now part of the WWWApp interface
- Updated the Icon module and added icons to the distribution file
- Added a Stream to Chunk converter for easier conversion of streams into dynamic memory buffers
- Introduced HTLib as a new core module. It contains generic information about the core which used to be in the HTAccess module.
- Added support for HTTP/1.1. Most of the HTTP/1.1 specification is now in place, we still need some headers and some features but this version can be considered to be compliant.
- Added suport for proxy authentication as specified by HTTP/1.1
- Added support for case-insensitive searching for proxies via environment variables
- Changed handling of proxies so that they are not included in the URL but is now instead part of the request object. This allows for better handling of proxies and also for more freely use of the proxy filter as it doesn't affect the other filters anymore.

### Bug Fixes

- Fixed problem with uploading directory listing using chunked encoding
- Fixed problem in the rule file parser. It didn't parse the last line of the config file
- Fixed autoconf to handle WAIS and updated the HTWAIS.c module
- Fixed race problem in PUT on alphas which caused the PUT operation to hang under certain circumstances

## Release 4.1b1 May 20 1996

### New Features

- Introduced GNU autoconf configure script for compiling on Unix platforms instead of the old BUILD script. This should make it a lot easier to compile on Unix as we get all the advantages of GNU autoconf.
- Introduction of the HTUserprofile Class which keeps track of a "user" known to the Library
- New access authentication interface allowing for dynamic registration of new access authentication mechanisms. It provides an easy API for hooking in new schemes.
- Improved handling of trace messages which allows for easy redirection of trace messages
- Support for registration of content coders/decoders and content transfer encoders/decoders. This is done the same way as for media types by registering a set of streams that can handle the various encodings.
- Support for chunked decoding
- Introduction of the HTHost Class which keeps track of information about remote hosts
- The DNS Class has been simplified to handle DNS queries only. All additional information about the remote host is defined by the HThost Class.
- We have a new HTEvent module which allows for dynamic registration of an event manager. This will make it much easier to use external event managers together with libwww. If you wish to continue to use the event loop from HTEvntrg, you must register it explicitly with HTEventrgInit. This call is demonstrated in HTBrowse.
- The HTStream module has been created containing a set of basiv streams such as an error stream etc.
- Introduction of the HTTransport Class. This allows for dynamic registration of transport protocols such as for example the W3Mux protocol, TCP access, local file access etc.
- All MIME parsing is now done with registered parsers. The HTMIME module only unwraps the MIME header fields and calls the best parser. The header parsing origonally done in HTMIME can be found in HTInit.c and is registered with HTMIMEInit. This call is demonstrated in HTBrowse.