/*

  					W3C Sample Code Library libwww Proxies and Gateways


!
  Proxy and gateway Manager
!
*/

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

/*

This module keeps a list of proxies and gateways to be contacted on a request
in stead of requesting it directly from the origin server. The module replaces
the old system of environment variables for gateways and proxies. However
for backward compatibility there is a function that reads the environment
variables at start up. Note that there is a difference between a proxy and
a gateway - the difference is the way the URL is set up in the
RequestLine of the HTTP request. If the original, full URL looks
like "http://www.w3.org/test.html" then the result will for
a proxy is "http://www.w3.org/test.html" and a gateway
"/www.w3.org/test.html"

The module is implemented by HTProxy.c, and it is
a part of the  W3C Sample Code
Library.
*/
#ifndef HTPROXY_H
#define HTPROXY_H

#include "HTList.h"

/*
.
  Registering a Proxy Server
.

A proxy server is registered with a corresponding access method, for example
http, ftp etc. The `proxy' parameter should be a fully
valid name, like http://proxy.w3.org:8001 but domain name is
not required. If an entry exists for this access then delete it and use the
new one.
*/

extern BOOL HTProxy_add		(const char * access, const char * proxy);

/*
(
  Registering a Proxy Using Regular Expressions
)

Registers a proxy as the server to contact for any URL matching the regular
expression. This requires that you have compiled with the
HT_POSIX_REGEX flag, see the installation
instructions. If you call this function without having compiled with
the HT_POSIX_REGEX flag then you will essentially get the non-regex
version.&nbsp;The name of the proxy should be a fully valid URL, like
"http://proxy.w3.org:8001". Returns YES if OK, else NO
*/

extern BOOL HTProxy_addRegex (const char * regex,
                              const char * proxy,
                              int regex_flags);

/*
(
  Deleting All Registered Proxies
)
*/

extern BOOL HTProxy_deleteAll	(void);

/*

The remove function removes all registered proxies. This is automatically
done in  HTLibTerminate() 
.
  Registering a No Proxy Location
.

The noproxy list is a list of host names and domain names where
we don't contact a proxy even though a proxy is in fact registered for this
particular access method . When registering a noproxy item, you
can specify a specific port for this access method in which case it isvalid
only for requests to this port. If `port' is '0' then it applies to all ports
and if `access' is NULL then it applies to to all access methods. Examples
of host names are w3.org and www.close.com
*/

extern BOOL HTNoProxy_add	(const char * host, const char * access,
				 unsigned port);

/*
(
  Registering a NoProxy Location Using Regular Expressions
)

Registers a regular expression where URIs matching this expression should
go directly and not via a proxy. Examples:
http://<star>\.w3\.org and
http://www\.noproxy\.com/<star> (I use
<star> in order not interfere with C comments) This requires
that you have compiled with the HT_POSIX_REGEX flag, see the
installation instructions. If you call this
function without having compiled with the HT_POSIX_REGEX flag then
you will essentially get the non-regex version.&nbsp;
*/

extern BOOL HTNoProxy_addRegex (const char * regex, int regex_flags);

/*
(
  Delete all Noproxy Destinations
)
*/

extern BOOL HTNoProxy_deleteAll	(void);

/*

The remove function removes all entries in the list. This is automatically
done in  HTLibTerminate()
(
  Inverse the meaning of the NoProxy list
)

Allows to change the value of a flag so that the NoProxy list is interpreted
as if it were an OnlyProxy list.
*/

extern int  HTProxy_NoProxyIsOnlyProxy (void);
extern void HTProxy_setNoProxyIsOnlyProxy (int value);

/*
.
  Look for a Proxy server
.

This function evaluates the lists of registered proxies and if one is found
for the actual access method and it is not registered in the `noproxy' list,
then a URL containing the host to be contacted is returned to the caller.
This string must be freed be the caller.
*/

extern char * HTProxy_find	(const char * url);

/*
.
  Registering a gateway
.

A gateway is registered with a corresponding access method, for example
http, ftp etc. The `gate' parameter should be a fully valid
name, like http://gateway.w3.org:8001 but domain name is not
required. If an entry exists for this access then delete it and use the new
one.
*/

extern BOOL HTGateway_add	(const char * access, const char * gate);
extern BOOL HTGateway_deleteAll	(void);

/*

The remove function removes all registered proxies. This is automatically
done in  HTLibTerminate()
.
  Look for a Gateway
.

This function evaluates the lists of registered gateways and if one is found
for the actual access method then it is returned and must be freed by the
caller.
*/

extern char * HTGateway_find	(const char * url);

/*
.
  Backwards Compability with Environment Variables
.

This function maintains backwards compatibility with the old environment
variables and searches for the most common values: http, ftp, news, wais,
and gopher
*/

extern void HTProxy_getEnvVar	(void);

/*
*/

#endif /* HTPROXY_H */

/*

  

  @(#) $Id: HTProxy.html,v 2.14 2000/02/29 14:25:59 kahan Exp $

*/
