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<h3>Apache HTTP Server Version 1.3</h3>
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<h1 align="CENTER">Module mod_isapi</h1>
<p>This module supports ISAPI Extensions within Apache for
Windows.</p>
<p><a href="module-dict.html#Status"
rel="Help"><strong>Status:</strong></a> Base<br />
<a href="module-dict.html#SourceFile"
rel="Help"><strong>Source File:</strong></a> mod_isapi.c<br />
<a href="module-dict.html#ModuleIdentifier"
rel="Help"><strong>Module Identifier:</strong></a>
isapi_module<br />
<a href="module-dict.html#Compatibility"
rel="Help"><strong>Compatibility:</strong></a> WIN32 only</p>
<h2>Summary</h2>
<p>This module implements the Internet Server extension API. It
allows Internet Server extensions (<em>e.g.</em> ISAPI .dll
modules) to be served by Apache for Windows, subject to the
noted restrictions.</p>
<p>ISAPI extension modules (.dll files) are written by third
parties. The Apache Group does not author these modules, so we
provide no support for them. Please contact the ISAPI's author
directly if you are experiencing problems running their ISAPI
extention. <strong>Please <em>do not</em> post such problems to
Apache's lists or bug reporting pages.</strong></p>
<h2>Directives</h2>
<ul>
<li><a
href="#isapireadaheadbuffer">ISAPIReadAheadBuffer</a></li>
<li><a
href="#isapilognotsupported">ISAPILogNotSupported</a></li>
<li><a
href="#isapiappendlogtoerrors">ISAPIAppendLogToErrors</a></li>
<li><a
href="#isapiappendlogtoquery">ISAPIAppendLogToQuery</a></li>
</ul>
<h2>Usage</h2>
<p>In the server configuration file, use the AddHandler
directive to associate ISAPI files with the
<code>isapi-isa</code> handler, and map it to the with their
file extensions. To enable any .dll file to be processed as an
ISAPI extention, edit the httpd.conf file and add the following
line:</p>
<pre>
AddHandler isapi-isa .dll
</pre>
<p>ISAPI extensions are governed by the same permissions and
restrictions as CGI scripts. That is, <code>Options
ExecCGI</code> must be set for the directory that contains the
ISAPI .dll file.</p>
<p>Review the <a href="#notes">Additional Notes</a> and the <a
href="#journal">Programmer's Journal</a> for additional details
and clarification of the specific ISAPI support offered by
mod_isapi.</p>
<h2><a id="notes" name="notes">Additional Notes</a></h2>
<p>Apache's ISAPI implementation conforms to all of the ISAPI
2.0 specification, except for the "Microsoft-specific"
extensions dealing with asynchronous I/O. Apache's I/O model
does not allow asynchronous reading and writing in a manner
that the ISAPI could access. If an ISA tries to access
unsupported features, including async I/O, a message is placed
in the error log to help with debugging. Since these messages
can become a flood, a new directive; <code>ISAPILogNotSupported
Off</code>, is introduced in Apache 1.3.13.</p>
<p>Some servers, like Microsoft IIS, load the ISA into the
server, and keep it loaded until memory usage is too high, or
specific configuration options are used. Apache currently loads
and unloads the ISA for each request. This is inefficient, but
Apache's request model makes this method the only method that
currently works. Apache 2.0 is expected to support more
effective loading and caching methods, with more precise
control over individual ISAPI modules and directories.</p>
<p>Also, remember that while Apache supports ISAPI Extensions,
it <strong>does not support ISAPI Filters.</strong> Support for
filters may be added at a later date, but no support is planned
at this time.</p>
<h2><a id="journal" name="journal">Programmer's
Journal</a></h2>
<p>If you are programming Apache 1.3 mod_isapi modules, you
must limit your calls to ServerSupportFunction to the following
directives:</p>
<dl>
<dt>HSE_REQ_SEND_URL_REDIRECT_RESP</dt>
<dd>Redirect the user to another location.<br />
This must be a fully qualified URL (e.g.
http://server/location).</dd>
<dt>HSE_REQ_SEND_URL</dt>
<dd>Redirect the user to another location.<br />
This cannot be a fully qualified URL, you are not allowed to
pass the protocol or a server name (e.g. simply
/location).<br />
This redirection is handled by the server, not the
browser.<br />
<strong>Warning:</strong> in their recent documentation,
Microsoft appears to have abandoned the distinction between
the two HSE_REQ_SEND_URL functions. Apache continues to treat
them as two distinct functions with different requirements
and behaviors.</dd>
<dt>HSE_REQ_SEND_RESPONSE_HEADER</dt>
<dd>Apache accepts a response body following the header if it
follows the blank line (two consecutive newlines) in the
headers string argument. This body cannot contain NULLs,
since the headers argument is NULL terminated.</dd>
<dt>HSE_REQ_DONE_WITH_SESSION</dt>
<dd>Apache considers this a no-op, since the session will be
finished when the ISAPI returns from processing.</dd>
<dt>HSE_REQ_MAP_URL_TO_PATH</dt>
<dd>Apache will translate a virtual name to a physical
name.</dd>
<dt>HSE_APPEND_LOG_PARAMETER <em>Apache 1.3.13 and
later</em></dt>
<dd>
This logged message may be captured in any of the following
logs:
<ul>
<li>in the \"%{isapi-parameter}n\" component in a
CustomLog directive</li>
<li>in the %q log component with the
ISAPIAppendLogToQuery On directive</li>
<li>in the error log with the ISAPIAppendLogToErrors On
directive</li>
</ul>
The first option, the %{isapi-parameter}n component, is
always available and prefered.
</dd>
<dt>HSE_REQ_IS_KEEP_CONN <em>Apache 1.3.13 and
later</em></dt>
<dd>Will return the negotiated Keep-Alive status.</dd>
<dt>HSE_REQ_SEND_RESPONSE_HEADER_EX <em>Apache 1.3.13 and
later</em></dt>
<dd>Will behave as documented, although the fKeepConn flag is
ignored.</dd>
<dt>HSE_REQ_IS_CONNECTED <em>Apache 1.3.13 and
later</em></dt>
<dd>Will report false if the request has been aborted.</dd>
</dl>
<p>Apache returns FALSE to any unsupported call to
ServerSupportFunction, and sets the GetLastError value to
ERROR_INVALID_PARAMETER.</p>
<p>Prior to Apache 1.3.13, ReadClient was a noop, and any
request with a request body greater than 48kb was rejected by
mod_isapi. As of Apache 1.3.13, ReadClient now retrieves the
request body exceeding the initial buffer (defined by
ISAPIReadAheadBuffer). Based on the ISAPIReadAheadBuffer
setting (number of bytes to buffer prior to calling the ISAPI
handler) shorter requests are sent complete to the extension
when it is invoked. If the request is longer, the ISAPI
extension must use ReadClient to retrieve the remaining request
body.</p>
<p>WriteClient is supported, but only with the HSE_IO_SYNC flag
or no option flag (value of 0). Any other WriteClient request
will be rejected with a return value of FALSE, and a
GetLastError value of ERROR_INVALID_PARAMETER.</p>
<p>GetServerVariable is supported, although extended server
variables do not exist (as defined by other servers.) All the
usual Apache CGI environment variables are available from
GetServerVariable. As of Apache 1.3.13, the ALL_HTTP and
ALL_RAW and variables are now available.</p>
<p>Apache 2.0 mod_isapi may support additional features
introduced in later versions of the ISAPI specification, as
well as limited emulation of async I/O and the TransmitFile
semantics. Apache 2.0 may also support caching of ISAPI .dlls
for performance. No further enhancements to the Apache 1.3
mod_isapi features are anticipated.</p>
<hr />
<h2><a id="isapireadaheadbuffer"
name="isapireadaheadbuffer">ISAPIReadAheadBuffer
directive</a></h2>
<a href="directive-dict.html#Syntax"
rel="Help"><strong>Syntax:</strong></a> ISAPIReadAheadBuffer
<em>size</em><br />
<a href="directive-dict.html#Default"
rel="Help"><strong>Default:</strong></a> 49152<br />
<a href="directive-dict.html#Context"
rel="Help"><strong>Context:</strong></a> server config<br />
<a href="directive-dict.html#Override"
rel="Help"><strong>Override:</strong></a> None<br />
<a href="directive-dict.html#Status"
rel="Help"><strong>Status:</strong></a> Base<br />
<a href="directive-dict.html#Module"
rel="Help"><strong>Module:</strong></a> mod_isapi<br />
<a href="module-dict.html#Compatibility"
rel="Help"><strong>Compatibility:</strong></a> Apache 1.3.13
and later, Win32 only
<p>Defines the maximum size of the Read Ahead Buffer sent to
ISAPI extentions when they are initally invoked. All remaining
data must be retrieved using the ReadClient callback; some
ISAPI extensions may not support the ReadClient function. Refer
questions to the ISAPI extention's author.</p>
<hr />
<h2><a id="isapilognotsupported"
name="isapilognotsupported">ISAPILogNotSupported
directive</a></h2>
<a href="directive-dict.html#Syntax"
rel="Help"><strong>Syntax:</strong></a> ISAPILogNotSupported
on|off<br />
<a href="directive-dict.html#Default"
rel="Help"><strong>Default:</strong></a> on<br />
<a href="directive-dict.html#Context"
rel="Help"><strong>Context:</strong></a> server config<br />
<a href="directive-dict.html#Override"
rel="Help"><strong>Override:</strong></a> None<br />
<a href="directive-dict.html#Status"
rel="Help"><strong>Status:</strong></a> Base<br />
<a href="directive-dict.html#Module"
rel="Help"><strong>Module:</strong></a> mod_isapi<br />
<a href="module-dict.html#Compatibility"
rel="Help"><strong>Compatibility:</strong></a> Apache 1.3.13
and later, Win32 only
<p>Logs all requests for unsupported features from ISAPI
extentions in the server error log. While this should be turned
off once all desired ISAPI modules are functioning, it defaults
to on to help administrators track down problems.</p>
<hr />
<h2><a id="isapiappendlogtoerrors"
name="isapiappendlogtoerrors">ISAPIAppendLogToErrors
directive</a></h2>
<a href="directive-dict.html#Syntax"
rel="Help"><strong>Syntax:</strong></a> ISAPIAppendLogToErrors
on|off<br />
<a href="directive-dict.html#Default"
rel="Help"><strong>Default:</strong></a> off<br />
<a href="directive-dict.html#Context"
rel="Help"><strong>Context:</strong></a> server config<br />
<a href="directive-dict.html#Override"
rel="Help"><strong>Override:</strong></a> None<br />
<a href="directive-dict.html#Status"
rel="Help"><strong>Status:</strong></a> Base<br />
<a href="directive-dict.html#Module"
rel="Help"><strong>Module:</strong></a> mod_isapi<br />
<a href="module-dict.html#Compatibility"
rel="Help"><strong>Compatibility:</strong></a> Apache 1.3.13
and later, Win32 only
<p>Record HSE_APPEND_LOG_PARAMETER requests from ISAPI
extentions to the server error log.</p>
<hr />
<h2><a id="isapiappendlogtoquery"
name="isapiappendlogtoquery">ISAPIAppendLogToQuery
directive</a></h2>
<a href="directive-dict.html#Syntax"
rel="Help"><strong>Syntax:</strong></a> ISAPIAppendLogToQuery
on|off<br />
<a href="directive-dict.html#Default"
rel="Help"><strong>Default:</strong></a> off<br />
<a href="directive-dict.html#Context"
rel="Help"><strong>Context:</strong></a> server config<br />
<a href="directive-dict.html#Override"
rel="Help"><strong>Override:</strong></a> None<br />
<a href="directive-dict.html#Status"
rel="Help"><strong>Status:</strong></a> Base<br />
<a href="directive-dict.html#Module"
rel="Help"><strong>Module:</strong></a> mod_isapi<br />
<a href="module-dict.html#Compatibility"
rel="Help"><strong>Compatibility:</strong></a> Apache 1.3.13
and later, Win32 only
<p>Record HSE_APPEND_LOG_PARAMETER requests from ISAPI
extentions to the query field (appended to the CustomLog %q
component).</p>
<p> <hr />
<h3 align="CENTER">Apache HTTP Server Version 1.3</h3>
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distrib
>
Mandriva
>
2010.0
>
i586
>
media
>
contrib-release
>
by-pkgid
>
d265f71d7fce441fd72dd0a77d0f8893
>
files
>
167
