W3C Sample Code Library libwww Default Initialization

# Default Initialization Methods

    /*
    **	(c) COPYRIGHT MIT 1995.
    **	Please first read the full copyright statement in the file COPYRIGH.
    */

As mentioned in the Library Architecture, libwww consists of a small core and a large set of hooks for adding functionality. By itself, the core it not capable of performing any Web related tasks like accessing a HTTP server or parsing a HTML document. All this functionality must be registered by the application. This way, the core of libwww is kept application independent and can be used as the basic building block for any kind of Web application. The Library comes with a large set of default functions, for example for accessing HTTP and FTP servers, parsing RFC 822 headers etc. This module helps the application programmer setting up all this functionality, but it is important to note that none of it is required in order to use the Library.

This module is implemented by HTInit.c, and it is a part of the W3C Sample Code Library. You can also have a look at the other Initialization modules.

    #ifndef HTINIT_H
    #define HTINIT_H
    #include "WWWLib.h"
    #include "WWWApp.h"

## Default Transport Protocol Modules

Register the default set of transport protocols.

    #include "WWWTrans.h"

    extern void HTTransportInit (void);

## Default Protocol Modules

Set up default bindings between access schemes and the set of protocol modules in the Library. The preemptive version registers all protocol modules to use blocking sockets.

    #include "WWWHTTP.h"
    #include "WWWFile.h"
    #include "WWWFTP.h"
    #include "WWWGophe.h"
    #include "WWWTelnt.h"
    #include "WWWNews.h"

    #ifdef HT_DIRECT_WAIS
    #include "WWWWAIS.h"
    #endif

    #ifndef FTP_PORT
    #define FTP_PORT	21
    #endif
    #ifndef NEWS_PORT
    #define NEWS_PORT	119
    #endif
    #ifndef GOPHER_PORT
    #define GOPHER_PORT	70
    #endif
    #ifndef WAIS_PORT
    #define WAIS_PORT	666
    #endif
    #ifndef HTTP_PORT
    #define HTTP_PORT	80
    #endif

    #define HTAccessInit	HTProtocolInit

    extern void HTProtocolInit (void);

    extern void HTProtocolPreemptiveInit (void);

## Default MIME Parsers

The core doesn't have any built in MIME parsers, but many of the protocols need them. For instance, many elements of the library rely on the `Content-Length` being correctly set. `HTMIMEInit()` provides the minimal functionality needed for library reliabilty.

    #include "WWWMIME.h"
    #include "WWWApp.h"

    extern void HTMIMEInit (void);

## Default Event Manager

libwww core does not have any default event loop - it has to be added by the application. However, it does come with an example implementation thta may be used. This implementation is based on a `select` system call using non-blocking and interleaved sockets.

    #include "WWWApp.h"

## Default Media Type Conversions

The Converters are used to convert a media type to another media type, or to present it on screen. This is a part of the stream stack algorithm. The Presenters are also used in the stream stack, but are initialized separately.

    #include "WWWMIME.h"
    #include "WWWHTML.h"
    #include "WWWStream.h"
    #include "WWWDir.h"
    #include "WWWCache.h"

    #ifdef HT_EXPAT
    #include "WWWXML.h"
    #endif

    extern void HTConverterInit	(HTList * conversions);

### Presenters

The Presenters are used to present media types by calling external programs, for example, a Postscript viewer. This is a part of the stream stack algorithm. The Converters are also used in the stream stack, but are initialized separately. The Presenters use the same include files as the Converters.

    extern void HTPresenterInit	(HTList * conversions);

### Converters and Presenters

This function is only defined in order to preserve backward compatibility.

    extern void HTFormatInit	(HTList * conversions);

## Default Transfer Encodings

Transfer encoders and decoders can handle encodings like chunked etc.

    #include "WWWHTTP.h"

    extern void HTTransferEncoderInit	(HTList * encodings);

## Default Content Encodings

Content encoders and decoders can handle encodings like deflate etc.

    #include "WWWZip.h"

    extern void HTContentEncoderInit	(HTList * encodings);

## Default BEFORE and AFTER Filters

This module provides a set of default BEFORE and AFTER filters that can be registered by the Net manager to be called before and after a request. All filters can be registered either to be called globally (all requests) or locally (pr request basis). Not done automaticly - may be done by application!

### BEFORE Filters

The BEFORE filters handle proxies, caches, rule files etc. The filters are called in the order by which the are registered

    #include "WWWApp.h"

    extern void HTBeforeInit (void);

### AFTER Filters

The AFTER filters handle error messages, logging, redirection, authentication etc. The filters are called in the order by which the are registered

    extern void HTAfterInit (void);

### BEFORE and AFTER Filters

This is just a short cut for registrating both BEFORE and AFTER at once

    extern void HTNetInit (void);

## Default Access Authentication Modules

The Access Manager which is implemented as a BEFORE and an AFTER filter (automatically registered in `HTNetInit()`) does not, by default, know of any access authentication schemes. As everything else, this must be registered! This function does the job and should be all you need.

    extern void HTAAInit (void);

## Default Message and Dialog Functions

We register a set of alert messages Not done automaticly - may be done by application!

    #include "WWWApp.h"

    extern void HTAlertInit (void);

## Default Icons for Directory Listings

The WWWDir interface contains support for including references (URLs and `ALT` text tags) to icons in directory listings. The icons are selected as a function of the media type and the content encoding of the file in question. That is - you can set up icons for compressed files, postscript files etc. There is also a small set of specific icons representing directories etc.

    #include "WWWFile.h"

    extern void HTIconInit (const char * url_prefix);

    #endif