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author	Henning Brauer <henning@cvs.openbsd.org>	2003-11-17 19:13:44 +0000
committer	Henning Brauer <henning@cvs.openbsd.org>	2003-11-17 19:13:44 +0000
commit	812876ad84ade0a7181de71c1feea1e35c2c0f11 (patch)
tree	a3e62b2a5f6318cc8f94d4b24d42397f25011393 /usr.sbin/httpd/htdocs
parent	2e2a7c9115e15c5017e54216522c848015cb8778 (diff)

these are gone since some time too

Diffstat (limited to 'usr.sbin/httpd/htdocs')

-rw-r--r--

usr.sbin/httpd/htdocs/manual/content-negotiation.html

674

-rw-r--r--

usr.sbin/httpd/htdocs/manual/mod/mod_log_config.html

408

2 files changed, 0 insertions, 1082 deletions

diff --git a/usr.sbin/httpd/htdocs/manual/content-negotiation.html b/usr.sbin/httpd/htdocs/manual/content-negotiation.html
deleted file mode 100644
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--- a/usr.sbin/httpd/htdocs/manual/content-negotiation.html
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@@ -1,674 +0,0 @@

-<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

- "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

-<html xmlns="http://www.w3.org/1999/xhtml">

- <head>

- <meta name="generator" content="HTML Tidy, see www.w3.org" />

- <title>Apache Content Negotiation</title>

- </head>

-

- <body bgcolor="#FFFFFF" text="#000000" link="#0000FF"

- vlink="#000080" alink="#FF0000">

- <div align="CENTER">

- <img src="images/sub.gif" alt="[APACHE DOCUMENTATION]" />

- <h3>Apache HTTP Server</h3>

- </div>

- <h1 align="CENTER">Content Negotiation</h1>

- <p>Apache's support for content negotiation has been updated to

- meet the HTTP/1.1 specification. It can choose the best

- representation of a resource based on the browser-supplied

- preferences for media type, languages, character set and

- encoding. It is also implements a couple of features to give

- more intelligent handling of requests from browsers which send

- incomplete negotiation information.</p>

- <p>Content negotiation is provided by the <a

- href="mod/mod_negotiation.html">mod_negotiation</a> module,

- which is compiled in by default.</p>

- <hr />

- <h2>About Content Negotiation</h2>

- <p>A resource may be available in several different

- representations. For example, it might be available in

- different languages or different media types, or a combination.

- One way of selecting the most appropriate choice is to give the

- user an index page, and let them select. However it is often

- possible for the server to choose automatically. This works

- because browsers can send as part of each request information

- about what representations they prefer. For example, a browser

- could indicate that it would like to see information in French,

- if possible, else English will do. Browsers indicate their

- preferences by headers in the request. To request only French

- representations, the browser would send</p>

-<pre>

- Accept-Language: fr

-</pre>

- <p>Note that this preference will only be applied when there is

- a choice of representations and they vary by language.</p>

- <p>As an example of a more complex request, this browser has

- been configured to accept French and English, but prefer

- French, and to accept various media types, preferring HTML over

- plain text or other text types, and preferring GIF or JPEG over

- other media types, but also allowing any other media type as a

- last resort:</p>

-<pre>

- Accept-Language: fr; q=1.0, en; q=0.5

- Accept: text/html; q=1.0, text/*; q=0.8, image/gif; q=0.6,

- image/jpeg; q=0.6, image/*; q=0.5, */*; q=0.1

-</pre>

- Apache 1.2 supports 'server driven' content negotiation, as

- defined in the HTTP/1.1 specification. It fully supports the

- Accept, Accept-Language, Accept-Charset and Accept-Encoding

- request headers. Apache 1.3.4 also supports 'transparent'

- content negotiation, which is an experimental negotiation

- protocol defined in RFC 2295 and RFC 2296. It does not offer

- support for 'feature negotiation' as defined in these RFCs.

- <p>A <strong>resource</strong> is a conceptual entity

- identified by a URI (RFC 2396). An HTTP server like Apache

- provides access to <strong>representations</strong> of the

- resource(s) within its namespace, with each representation in

- the form of a sequence of bytes with a defined media type,

- character set, encoding, etc. Each resource may be associated

- with zero, one, or more than one representation at any given

- time. If multiple representations are available, the resource

- is referred to as <strong>negotiable</strong> and each of its

- representations is termed a <strong>variant</strong>. The ways

- in which the variants for a negotiable resource vary are called

- the <strong>dimensions</strong> of negotiation.</p>

- <h2>Negotiation in Apache</h2>

- <p>In order to negotiate a resource, the server needs to be

- given information about each of the variants. This is done in

- one of two ways:</p>

- <ul>

- <li>Using a type map (<em>i.e.</em>, a <code>*.var</code>

- file) which names the files containing the variants

- explicitly, or</li>

- <li>Using a 'MultiViews' search, where the server does an

- implicit filename pattern match and chooses from among the

- results.</li>

- </ul>

- <h3>Using a type-map file</h3>

- <p>A type map is a document which is associated with the

- handler named <code>type-map</code> (or, for

- backwards-compatibility with older Apache configurations, the

- mime type <code>application/x-type-map</code>). Note that to

- use this feature, you must have a handler set in the

- configuration that defines a file suffix as

- <code>type-map</code>; this is best done with a</p>

-<pre>

- AddHandler type-map .var

-</pre>

- in the server configuration file. See the comments in the

- sample config file for more details.

- <p>Type map files have an entry for each available variant;

- these entries consist of contiguous HTTP-format header lines.

- Entries for different variants are separated by blank lines.

- Blank lines are illegal within an entry. It is conventional to

- begin a map file with an entry for the combined entity as a

- whole (although this is not required, and if present will be

- ignored). An example map file is:</p>

-<pre>

- URI: foo

- URI: foo.en.html

- Content-type: text/html

- Content-language: en

- URI: foo.fr.de.html

- Content-type: text/html;charset=iso-8859-2

- Content-language: fr, de

-</pre>

- If the variants have different source qualities, that may be

- indicated by the "qs" parameter to the media type, as in this

- picture (available as jpeg, gif, or ASCII-art):

-<pre>

- URI: foo

- URI: foo.jpeg

- Content-type: image/jpeg; qs=0.8

- URI: foo.gif

- Content-type: image/gif; qs=0.5

- URI: foo.txt

- Content-type: text/plain; qs=0.01

-</pre>

- <p>qs values can vary in the range 0.000 to 1.000. Note that

- any variant with a qs value of 0.000 will never be chosen.

- Variants with no 'qs' parameter value are given a qs factor of

- 1.0. The qs parameter indicates the relative 'quality' of this

- variant compared to the other available variants, independent

- of the client's capabilities. For example, a jpeg file is

- usually of higher source quality than an ascii file if it is

- attempting to represent a photograph. However, if the resource

- being represented is an original ascii art, then an ascii

- representation would have a higher source quality than a jpeg

- representation. A qs value is therefore specific to a given

- variant depending on the nature of the resource it

- represents.</p>

- <p>The full list of headers recognized is:</p>

- <dl>

- <dt><code>URI:</code></dt>

- <dd>uri of the file containing the variant (of the given

- media type, encoded with the given content encoding). These

- are interpreted as URLs relative to the map file; they must

- be on the same server (!), and they must refer to files to

- which the client would be granted access if they were to be

- requested directly.</dd>

- <dt><code>Content-Type:</code></dt>

- <dd>media type --- charset, level and "qs" parameters may be

- given. These are often referred to as MIME types; typical

- media types are <code>image/gif</code>,

- <code>text/plain</code>, or

- <code>text/html; level=3</code>.</dd>

- <dt><code>Content-Language:</code></dt>

- <dd>The languages of the variant, specified as an Internet

- standard language tag from RFC 1766 (<em>e.g.</em>,

- <code>en</code> for English, <code>kr</code> for Korean,

- <em>etc.</em>).</dd>

- <dt><code>Content-Encoding:</code></dt>

- <dd>If the file is compressed, or otherwise encoded, rather

- than containing the actual raw data, this says how that was

- done. Apache only recognizes encodings that are defined by an

- <a href="mod/mod_mime.html#addencoding">AddEncoding</a>

- directive. This normally includes the encodings

- <code>x-compress</code> for compress'd files, and

- <code>x-gzip</code> for gzip'd files. The <code>x-</code>

- prefix is ignored for encoding comparisons.</dd>

- <dt><code>Content-Length:</code></dt>

- <dd>The size of the file. Specifying content lengths in the

- type-map allows the server to compare file sizes without

- checking the actual files.</dd>

- <dt><code>Description:</code></dt>

- <dd>A human-readable textual description of the variant. If

- Apache cannot find any appropriate variant to return, it will

- return an error response which lists all available variants

- instead. Such a variant list will include the human-readable

- variant descriptions.</dd>

- </dl>

- <h3>Multiviews</h3>

- <p><code>MultiViews</code> is a per-directory option, meaning

- it can be set with an <code>Options</code> directive within a

- <code><Directory></code>, <code><Location></code>

- or <code><Files></code> section in

- <code>access.conf</code>, or (if <code>AllowOverride</code> is

- properly set) in <code>.htaccess</code> files. Note that

- <code>Options All</code> does not set <code>MultiViews</code>;

- you have to ask for it by name.</p>

- <p>The effect of <code>MultiViews</code> is as follows: if the

- server receives a request for <code>/some/dir/foo</code>, if

- <code>/some/dir</code> has <code>MultiViews</code> enabled, and

- <code>/some/dir/foo</code> does <em>not</em> exist, then the

- server reads the directory looking for files named foo.*, and

- effectively fakes up a type map which names all those files,

- assigning them the same media types and content-encodings it

- would have if the client had asked for one of them by name. It

- then chooses the best match to the client's requirements.</p>

- <p><code>MultiViews</code> may also apply to searches for the

- file named by the <code>DirectoryIndex</code> directive, if the

- server is trying to index a directory. If the configuration

- files specify</p>

-<pre>

- DirectoryIndex index

-</pre>

- then the server will arbitrate between <code>index.html</code>

- and <code>index.html3</code> if both are present. If neither

- are present, and <code>index.cgi</code> is there, the server

- will run it.

- <p>If one of the files found when reading the directive is a

- CGI script, it's not obvious what should happen. The code gives

- that case special treatment --- if the request was a POST, or a

- GET with QUERY_ARGS or PATH_INFO, the script is given an

- extremely high quality rating, and generally invoked; otherwise

- it is given an extremely low quality rating, which generally

- causes one of the other views (if any) to be retrieved.</p>

- <h2>The Negotiation Methods</h2>

- After Apache has obtained a list of the variants for a given

- resource, either from a type-map file or from the filenames in

- the directory, it invokes one of two methods to decide on the

- 'best' variant to return, if any. It is not necessary to know

- any of the details of how negotiation actually takes place in

- order to use Apache's content negotiation features. However the

- rest of this document explains the methods used for those

- interested.

- <p>There are two negotiation methods:</p>

- <ol>

- <li><strong>Server driven negotiation with the Apache

- algorithm</strong> is used in the normal case. The Apache

- algorithm is explained in more detail below. When this

- algorithm is used, Apache can sometimes 'fiddle' the quality

- factor of a particular dimension to achieve a better result.

- The ways Apache can fiddle quality factors is explained in

- more detail below.</li>

- <li><strong>Transparent content negotiation</strong> is used

- when the browser specifically requests this through the

- mechanism defined in RFC 2295. This negotiation method gives

- the browser full control over deciding on the 'best' variant,

- the result is therefore dependent on the specific algorithms

- used by the browser. As part of the transparent negotiation

- process, the browser can ask Apache to run the 'remote

- variant selection algorithm' defined in RFC 2296.</li>

- </ol>

- <h3>Dimensions of Negotiation</h3>

- <table>

- <tr valign="top">

- <th>Dimension</th>

- <th>Notes</th>

- </tr>

- <tr valign="top">

- <td>Media Type</td>

- <td>Browser indicates preferences with the Accept header

- field. Each item can have an associated quality factor.

- Variant description can also have a quality factor (the

- "qs" parameter).</td>

- </tr>

- <tr valign="top">

- <td>Language</td>

- <td>Browser indicates preferences with the Accept-Language

- header field. Each item can have a quality factor. Variants

- can be associated with none, one or more than one

- language.</td>

- </tr>

- <tr valign="top">

- <td>Encoding</td>

- <td>Browser indicates preference with the Accept-Encoding

- header field. Each item can have a quality factor.</td>

- </tr>

- <tr valign="top">

- <td>Charset</td>

- <td>Browser indicates preference with the Accept-Charset

- header field. Each item can have a quality factor. Variants

- can indicate a charset as a parameter of the media

- type.</td>

- </tr>

- </table>

- <h3>Apache Negotiation Algorithm</h3>

- <p>Apache can use the following algorithm to select the 'best'

- variant (if any) to return to the browser. This algorithm is

- not further configurable. It operates as follows:</p>

- <ol>

- <li>First, for each dimension of the negotiation, check the

- appropriate <em>Accept*</em> header field and assign a

- quality to each variant. If the <em>Accept*</em> header for

- any dimension implies that this variant is not acceptable,

- eliminate it. If no variants remain, go to step 4.</li>

- <li>

- Select the 'best' variant by a process of elimination. Each

- of the following tests is applied in order. Any variants

- not selected at each test are eliminated. After each test,

- if only one variant remains, select it as the best match

- and proceed to step 3. If more than one variant remains,

- move on to the next test.

- <ol>

- <li>Multiply the quality factor from the Accept header

- with the quality-of-source factor for this variant's

- media type, and select the variants with the highest

- value.</li>

- <li>Select the variants with the highest language quality

- factor.</li>

- <li>Select the variants with the best language match,

- using either the order of languages in the

- Accept-Language header (if present), or else the order of

- languages in the <code>LanguagePriority</code> directive

- (if present).</li>

- <li>Select the variants with the highest 'level' media

- parameter (used to give the version of text/html media

- types).</li>

- <li>Select variants with the best charset media

- parameters, as given on the Accept-Charset header line.

- Charset ISO-8859-1 is acceptable unless explicitly

- excluded. Variants with a <code>text/*</code> media type

- but not explicitly associated with a particular charset

- are assumed to be in ISO-8859-1.</li>

- <li>Select those variants which have associated charset

- media parameters that are <em>not</em> ISO-8859-1. If

- there are no such variants, select all variants

- instead.</li>

- <li>Select the variants with the best encoding. If there

- are variants with an encoding that is acceptable to the

- user-agent, select only these variants. Otherwise if

- there is a mix of encoded and non-encoded variants,

- select only the unencoded variants. If either all

- variants are encoded or all variants are not encoded,

- select all variants.</li>

- <li>Select the variants with the smallest content

- length.</li>

- <li>Select the first variant of those remaining. This

- will be either the first listed in the type-map file, or

- when variants are read from the directory, the one whose

- file name comes first when sorted using ASCII code

- order.</li>

- </ol>

- </li>

- <li>The algorithm has now selected one 'best' variant, so

- return it as the response. The HTTP response header Vary is

- set to indicate the dimensions of negotiation (browsers and

- caches can use this information when caching the resource).

- End.</li>

- <li><p>To get here means no variant was selected (because none

- are acceptable to the browser). Return a 406 status (meaning

- "No acceptable representation") with a response body

- consisting of an HTML document listing the available

- variants. Also set the HTTP Vary header to indicate the

- dimensions of variance.</p>

- <p>You should be aware that the error message returned by Apache is

- neccessarily rather terse and might confuse some users (even though it

- lists the available alternatives). If you want to avoid users seeing this

- error page, you should organize your documents such that a document in a

- default language (or with a default encoding etc.) is always returned if a

- document is not available in any of the languages, encodings etc. the

- browser asked for.</p>

- <p>In particular, if you want a document in a default language to

- be returned if a document is not available in any of the languages

- a browser asked for, you should create a document with no language

- attribute set. See <a href="#nolanguage">Variants with no

- Language</a> below for details.</p></li>

- </ol>

- <h2><a id="better" name="better">Fiddling with Quality

- Values</a></h2>

- <p>Apache sometimes changes the quality values from what would

- be expected by a strict interpretation of the Apache

- negotiation algorithm above. This is to get a better result

- from the algorithm for browsers which do not send full or

- accurate information. Some of the most popular browsers send

- Accept header information which would otherwise result in the

- selection of the wrong variant in many cases. If a browser

- sends full and correct information these fiddles will not be

- applied.</p>

- <h3>Media Types and Wildcards</h3>

- <p>The Accept: request header indicates preferences for media

- types. It can also include 'wildcard' media types, such as

- "image/*" or "*/*" where the * matches any string. So a request

- including:</p>

-<pre>

- Accept: image/*, */*

-</pre>

- would indicate that any type starting "image/" is acceptable,

- as is any other type (so the first "image/*" is redundant).

- Some browsers routinely send wildcards in addition to explicit

- types they can handle. For example:

-<pre>

- Accept: text/html, text/plain, image/gif, image/jpeg, */*

-</pre>

- The intention of this is to indicate that the explicitly listed

- types are preferred, but if a different representation is

- available, that is ok too. However under the basic algorithm,

- as given above, the */* wildcard has exactly equal preference

- to all the other types, so they are not being preferred. The

- browser should really have sent a request with a lower quality

- (preference) value for *.*, such as:

-<pre>

- Accept: text/html, text/plain, image/gif, image/jpeg, */*; q=0.01

-</pre>

- The explicit types have no quality factor, so they default to a

- preference of 1.0 (the highest). The wildcard */* is given a

- low preference of 0.01, so other types will only be returned if

- no variant matches an explicitly listed type.

- <p>If the Accept: header contains <em>no</em> q factors at all,

- Apache sets the q value of "*/*", if present, to 0.01 to

- emulate the desired behavior. It also sets the q value of

- wildcards of the format "type/*" to 0.02 (so these are

- preferred over matches against "*/*". If any media type on the

- Accept: header contains a q factor, these special values are

- <em>not</em> applied, so requests from browsers which send the

- correct information to start with work as expected.</p>

- <h3><a name="nolanguage">Variants with no Language</a></h3>

- <p>If some of the variants for a particular resource have a

- language attribute, and some do not, those variants with no

- language are given a very low language quality factor of

- 0.001.</p>

- <p>The reason for setting this language quality factor for variant

- with no language to a very low value is to allow for a default

- variant which can be supplied if none of the other variants match

- the browser's language preferences. This allows you to avoid users

- seeing a "406" error page if their browser is set to only accept

- languages which you do not offer for the ressource that was

- requested.</p>

- <p>For example, consider the situation with Multiviews enabled and

- three variants:</p>

- <ul>

- <li>foo.en.html, language en</li>

- <li>foo.fr.html, language en</li>

- <li>foo.html, no language</li>

- </ul>

- <p>The meaning of a variant with no language is that it is always

- acceptable to the browser. If the request is for <code>foo</code>

- and the Accept-Language header includes either en or fr (or both)

- one of foo.en.html or foo.fr.html will be returned. If the browser

- does not list either en or fr as acceptable, foo.html will be

- returned instead. If the client requests <code>foo.html</code>

- instead, then no negotation will occur since the exact match

- will be returned. To avoid this problem, it is sometimes helpful

- to name the "no language" variant <code>foo.html.html</code> to assure

- that Multiviews and language negotiation will come into play.</p>

- <h2>Extensions to Transparent Content Negotiation</h2>

- Apache extends the transparent content negotiation protocol

- (RFC 2295) as follows. A new <code>{encoding ..}</code> element

- is used in variant lists to label variants which are available

- with a specific content-encoding only. The implementation of

- the RVSA/1.0 algorithm (RFC 2296) is extended to recognize

- encoded variants in the list, and to use them as candidate

- variants whenever their encodings are acceptable according to

- the Accept-Encoding request header. The RVSA/1.0 implementation

- does not round computed quality factors to 5 decimal places

- before choosing the best variant.

- <h2>Note on hyperlinks and naming conventions</h2>

- <p>If you are using language negotiation you can choose between

- different naming conventions, because files can have more than

- one extension, and the order of the extensions is normally

- irrelevant (see <a href="mod/mod_mime.html">mod_mime</a>

- documentation for details).</p>

- <p>A typical file has a MIME-type extension (<em>e.g.</em>,

- <samp>html</samp>), maybe an encoding extension (<em>e.g.</em>,

- <samp>gz</samp>), and of course a language extension

- (<em>e.g.</em>, <samp>en</samp>) when we have different

- language variants of this file.</p>

- <p>Examples:</p>

- <ul>

- <li>foo.en.html</li>

- <li>foo.html.en</li>

- <li>foo.en.html.gz</li>

- </ul>

- <p>Here some more examples of filenames together with valid and

- invalid hyperlinks:</p>

- <table border="1" cellpadding="8" cellspacing="0">

- <tr>

- <th>Filename</th>

- <th>Valid hyperlink</th>

- <th>Invalid hyperlink</th>

- </tr>

- <tr>

- <td><em>foo.html.en</em></td>

- <td>foo<br />

- foo.html</td>

- <td>-</td>

- </tr>

- <tr>

- <td><em>foo.en.html</em></td>

- <td>foo</td>

- <td>foo.html</td>

- </tr>

- <tr>

- <td><em>foo.html.en.gz</em></td>

- <td>foo<br />

- foo.html</td>

- <td>foo.gz<br />

- foo.html.gz</td>

- </tr>

- <tr>

- <td><em>foo.en.html.gz</em></td>

- <td>foo</td>

- <td>foo.html<br />

- foo.html.gz<br />

- foo.gz</td>

- </tr>

- <tr>

- <td><em>foo.gz.html.en</em></td>

- <td>foo<br />

- foo.gz<br />

- foo.gz.html</td>

- <td>foo.html</td>

- </tr>

- <tr>

- <td><em>foo.html.gz.en</em></td>

- <td>foo<br />

- foo.html<br />

- foo.html.gz</td>

- <td>foo.gz</td>

- </tr>

- </table>

- <p>Looking at the table above you will notice that it is always

- possible to use the name without any extensions in an hyperlink

- (<em>e.g.</em>, <samp>foo</samp>). The advantage is that you

- can hide the actual type of a document rsp. file and can change

- it later, <em>e.g.</em>, from <samp>html</samp> to

- <samp>shtml</samp> or <samp>cgi</samp> without changing any

- hyperlink references.</p>

- <p>If you want to continue to use a MIME-type in your

- hyperlinks (<em>e.g.</em> <samp>foo.html</samp>) the language

- extension (including an encoding extension if there is one)

- must be on the right hand side of the MIME-type extension

- (<em>e.g.</em>, <samp>foo.html.en</samp>).</p>

- <h2>Note on Caching</h2>

- <p>When a cache stores a representation, it associates it with

- the request URL. The next time that URL is requested, the cache

- can use the stored representation. But, if the resource is

- negotiable at the server, this might result in only the first

- requested variant being cached and subsequent cache hits might

- return the wrong response. To prevent this, Apache normally

- marks all responses that are returned after content negotiation

- as non-cacheable by HTTP/1.0 clients. Apache also supports the

- HTTP/1.1 protocol features to allow caching of negotiated

- responses.</p>

- <p>For requests which come from a HTTP/1.0 compliant client

- (either a browser or a cache), the directive

- <tt>CacheNegotiatedDocs</tt> can be used to allow caching of

- responses which were subject to negotiation. This directive can

- be given in the server config or virtual host, and takes no

- arguments. It has no effect on requests from HTTP/1.1 clients.

- <hr />

- <h3 align="CENTER">Apache HTTP Server</h3>

- <a href="./"><img src="images/index.gif" alt="Index" /></a>

- </p>

- </body>

-</html>

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- <title>Apache module mod_log_config</title>

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- <h3>Apache HTTP Server Version 1.3</h3>

- </div>

- <h1 align="CENTER">Module mod_log_config</h1>

- <p>This module provides for logging of the requests made to the

- server, using the Common Log Format or a user-specified

- format.</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_log_config.c<br />

- <a href="module-dict.html#ModuleIdentifier"

- rel="Help"><strong>Module Identifier:</strong></a>

- config_log_module<br />

- <a href="module-dict.html#Compatibility"

- rel="Help"><strong>Compatibility:</strong></a> Was an extension

- module prior to Apache 1.2.</p>

- <h2>Summary</h2>

- <p>This module provides for flexible logging of client

- requests. Logs are written in a customizable format, and may be

- written directly to a file, or to an external program.

- Conditional logging is provided so that individual requests may

- be included or excluded from the logs based on characteristics

- of the request.</p>

- <p>Three directives are provided by this module:

- <code>TransferLog</code> to create a log file,

- <code>LogFormat</code> to set a custom format, and

- <code>CustomLog</code> to define a log file and format in one

- step. The <code>TransferLog</code> and <code>CustomLog</code>

- directives can be used multiple times in each server to cause

- each request to be logged to multiple files.</p>

- <p>See also: <a href="../logs.html">Apache Log Files</a>.</p>

- <h2>Directives</h2>

- <ul>

- <li><a href="#cookielog">CookieLog</a></li>

- <li><a href="#customlog">CustomLog</a></li>

- <li><a href="#logformat">LogFormat</a></li>

- <li><a href="#transferlog">TransferLog</a></li>

- </ul>

- <h2><a id="formats" name="formats">Custom Log Formats</a></h2>

- <p>The format argument to the <code>LogFormat</code> and

- <code>CustomLog</code> directives is a string. This string is

- logged to the log file for each request. It can contain literal

- characters copied into the log files and the c-type control

- characters "\n" and "\t" to represent new-lines and tabs.

- Literal quotes and back-slashes should be escaped with

- back-slashes.</p>

- <p>The characteristics of the request itself are logged by

- placing "%" directives in the format string, which are replaced

- in the log file by the values as follows:</p>

-<pre>

-%...a: Remote IP-address

-%...A: Local IP-address

-%...B: Bytes sent, excluding HTTP headers.

-%...b: Bytes sent, excluding HTTP headers. In CLF format

- i.e. a '-' rather than a 0 when no bytes are sent.

-%...c: Connection status when response is completed.

- 'X' = connection aborted before the response completed.

- '+' = connection may be kept alive after the response is sent.

- '-' = connection will be closed after the response is sent.

-%...{FOOBAR}e: The contents of the environment variable FOOBAR

-%...f: Filename

-%...h: Remote host

-%...H The request protocol

-%...{Foobar}i: The contents of Foobar: header line(s) in the request

- sent to the server.

-%...l: Remote logname (from identd, if supplied)

-%...m The request method

-%...{Foobar}n: The contents of note "Foobar" from another module.

-%...{Foobar}o: The contents of Foobar: header line(s) in the reply.

-%...p: The canonical Port of the server serving the request

-%...P: The process ID of the child that serviced the request.

-%...q The query string (prepended with a ? if a query string exists,

- otherwise an empty string)

-%...r: First line of request

-%...s: Status. For requests that got internally redirected, this is

- the status of the *original* request --- %...>s for the last.

-%...t: Time, in common log format time format (standard english format)

-%...{format}t: The time, in the form given by format, which should

- be in strftime(3) format. (potentially localized)

-%...T: The time taken to serve the request, in seconds.

-%...u: Remote user (from auth; may be bogus if return status (%s) is 401)

-%...U: The URL path requested, not including any query string.

-%...v: The canonical ServerName of the server serving the request.

-%...V: The server name according to the UseCanonicalName setting.

-</pre>

- <p>The "..." can be nothing at all (<em>e.g.</em>, <code>"%h %u

- %r %s %b"</code>), or it can indicate conditions for inclusion

- of the item (which will cause it to be replaced with "-" if the

- condition is not met). The forms of condition are a list of

- HTTP status codes, which may or may not be preceded by "!".

- Thus, "%400,501{User-agent}i" logs User-agent: on 400 errors

- and 501 errors (Bad Request, Not Implemented) only;

- "%!200,304,302{Referer}i" logs Referer: on all requests which

- did <strong>not</strong> return some sort of normal status.</p>

- <p>Note that there is no escaping performed on the strings from

- %...r, %...i and %...o. This is mainly to comply with the

- requirements of the Common Log Format. This implies that

- clients can insert control characters into the log, so care

- should be taken when dealing with raw log files.</p>

- <p>Some commonly used log format strings are:</p>

- <dl>

- <dt>Common Log Format (CLF)</dt>

- <dd><code>"%h %l %u %t \"%r\" %>s %b"</code></dd>

- <dt>Common Log Format with Virtual Host</dt>

- <dd><code>"%v %h %l %u %t \"%r\" %>s %b"</code></dd>

- <dt>NCSA extended/combined log format</dt>

- <dd><code>"%h %l %u %t \"%r\" %>s %b \"%{Referer}i\"

- \"%{User-agent}i\""</code></dd>

- <dt>Referer log format</dt>

- <dd><code>"%{Referer}i -> %U"</code></dd>

- <dt>Agent (Browser) log format</dt>

- <dd><code>"%{User-agent}i"</code></dd>

- </dl>

- <p>Note that the canonical <a

- href="core.html#servername">ServerName</a> and <a

- href="core.html#port">Port</a> of the server serving the

- request are used for <code>%v</code> and <code>%p</code>

- respectively. This happens regardless of the <a

- href="core.html#usecanonicalname">UseCanonicalName</a> setting

- because otherwise log analysis programs would have to duplicate

- the entire vhost matching algorithm in order to decide what

- host really served the request.</p>

- <h2>Security Considerations</h2>

- <p>See the <a

- href="../misc/security_tips.html#serverroot">security tips</a>

- document for details on why your security could be compromised

- if the directory where logfiles are stored is writable by

- anyone other than the user that starts the server.</p>

- <h2>Compatibility notes</h2>

- <ul>

- <li>This module is based on mod_log_config distributed with

- previous Apache releases, now updated to handle multiple

- logs. There is now no need to re-configure Apache to use

- configuration log formats.</li>

- <li>The module also implements the <code>CookieLog</code>

- directive, used to log user-tracking information created by

- <a href="mod_usertrack.html">mod_usertrack</a>. The use of

- <code>CookieLog</code> is deprecated, and a

- <code>CustomLog</code> should be defined to log user-tracking

- information instead.</li>

- <li>As of Apache 1.3.5, this module allows conditional

- logging based upon the setting of <a

- href="../env.html">environment variables</a>. That is, you

- can control whether a request should be logged or not based

- upon whether an arbitrary environment variable is defined or

- not. This is configurable on a <em>per</em>-logfile

- basis.</li>

- <li>Beginning with Apache 1.3.5, the mod_log_config module

- has also subsumed the <code>RefererIgnore</code>

- functionality from <a

- href="mod_log_referer.html">mod_log_referer</a>. The effect

- of <code>RefererIgnore</code> can be achieved by combinations

- of <a href="mod_setenvif.html"><code>SetEnvIf</code></a>

- directives and conditional <code>CustomLog</code>

- definitions.</li>

- </ul>

- <hr />

- <h2><a id="cookielog" name="cookielog">CookieLog</a>

- directive</h2>

- <p><a href="directive-dict.html#Syntax"

- rel="Help"><strong>Syntax:</strong></a> CookieLog

- <em>filename</em><br />

- <a href="directive-dict.html#Context"

- rel="Help"><strong>Context:</strong></a> server config, virtual

- host<br />

- <a href="directive-dict.html#Module"

- rel="Help"><strong>Module:</strong></a> mod_cookies<br />

- <a href="directive-dict.html#Compatibility"

- rel="Help"><strong>Compatibility:</strong></a> Only available

- in Apache 1.2 and above</p>

- <p>The CookieLog directive sets the filename for logging of

- cookies. The filename is relative to the <a

- href="core.html#serverroot">ServerRoot</a>. This directive is

- included only for compatibility with <a

- href="mod_cookies.html">mod_cookies</a>, and is deprecated.</p>

- <hr />

- <h2><a id="customlog" name="customlog">CustomLog</a> <a

- id="customlog-conditional"

- name="customlog-conditional">directive</a></h2>

- <p><a href="directive-dict.html#Syntax"

- rel="Help"><strong>Syntax:</strong></a> CustomLog

- <em>file</em>|<em>pipe</em> <em>format</em>|<em>nickname</em>

- [env=[!]<em>environment-variable</em>]<br />

- <a href="directive-dict.html#Context"

- rel="Help"><strong>Context:</strong></a> server config, virtual

- host<br />

- <a href="directive-dict.html#Status"

- rel="Help"><strong>Status:</strong></a> Base<br />

- <a href="directive-dict.html#Compatibility"

- rel="Help"><strong>Compatibility:</strong></a> Nickname only

- available in Apache 1.3 or later. Conditional logging available

- in 1.3.5 or later.<br />

- <a href="directive-dict.html#Module"

- rel="Help"><strong>Module:</strong></a> mod_log_config</p>

- <p>The <code>CustomLog</code> directive is used to log requests

- to the server. A log format is specified, and the logging can

- optionally be made conditional on request characteristics using

- environment variables.</p>

- <p>The first argument, which specifies the location to which

- the logs will be written, can take on one of the following two

- types of values:</p>

- <dl>

- <dt><em>file</em></dt>

- <dd>A filename, relative to the <a

- href="core.html#serverroot">ServerRoot</a>.</dd>

- <dt><em>pipe</em></dt>

- <dd>The pipe character "<code>|</code>", followed by the path

- to a program to receive the log information on its standard

- input. <strong>Security:</strong> if a program is used, then

- it will be run under the user who started httpd. This will be

- root if the server was started by root; be sure that the

- program is secure.</dd>

- </dl>

- <p>The second argument specifies what will be written to the

- log file. It can specify either a <em>nickname</em> defined by

- a previous <a href="#logformat">LogFormat</a> directive, or it

- can be an explicit <em>format</em> string as described in the

- <a href="#formats">log formats</a> section.</p>

- <p>For example, the following two sets of directives have

- exactly the same effect:</p>

-<pre>

- # CustomLog with format nickname

- LogFormat "%h %l %u %t \"%r\" %>s %b" common

- CustomLog logs/access_log common

- # CustomLog with explicit format string

- CustomLog logs/access_log "%h %l %u %t \"%r\" %>s %b"

-</pre>

- <p>The third argument is optional and allows the decision on

- whether or not to log a particular request to be based on the

- presence or absence of a particular variable in the server

- environment. If the specified <a href="../env.html">environment

- variable</a> is set for the request (or is not set, in the case

- of a '<code>env=!<em>name</em></code>' clause), then the

- request will be logged.</p>

- <p>Environment variables can be set on a <em>per</em>-request

- basis using the <a href="mod_setenvif.html">mod_setenvif</a>

- and/or <a href="mod_rewrite.html">mod_rewrite</a> modules. For

- example, if you want to record requests for all GIF

- images on your server in a separate logfile but not in your main

- log, you can use:</p>

-<pre>

- SetEnvIf Request_URI \.gif$ gif-image

- CustomLog gif-requests.log common env=gif-image

- CustomLog nongif-requests.log common env=!gif-image

-</pre>

- <hr />

- <h2><a id="logformat" name="logformat">LogFormat</a>

- directive</h2>

- <p><a href="directive-dict.html#Syntax"

- rel="Help"><strong>Syntax:</strong></a> LogFormat

- <em>format</em>|<em>nickname</em> [<em>nickname</em>]<br />

- <a href="directive-dict.html#Default"

- rel="Help"><strong>Default:</strong></a> <code>LogFormat "%h %l

- %u %t \"%r\" %>s %b"</code><br />

- <a href="directive-dict.html#Context"

- rel="Help"><strong>Context:</strong></a> server config, virtual

- host<br />

- <a href="directive-dict.html#Status"

- rel="Help"><strong>Status:</strong></a> Base<br />

- <a href="directive-dict.html#Compatibility"

- rel="Help"><strong>Compatibility:</strong></a> Nickname only

- available in Apache 1.3 or later<br />

- <a href="directive-dict.html#Module"

- rel="Help"><strong>Module:</strong></a> mod_log_config</p>

- <p>This directive specifies the format of the access log

- file.</p>

- <p>The <code>LogFormat</code> directive can take one of two

- forms. In the first form, where only one argument is specified,

- this directive sets the log format which will be used by logs

- specified in subsequent <a href="#transferlog">TransferLog</a>

- directives. The single argument can specify an explicit

- <em>format</em> as discussed in <a href="#formats">custom log

- formats</a> section above. Alternatively, it can use a

- <em>nickname</em> to refer to a log format defined in a

- previous <code>LogFormat</code> directive as described

- below.</p>

- <p>The second form of the <code>LogFormat</code> directive

- associates an explicit <em>format</em> with a

- <em>nickname</em>. This <em>nickname</em> can then be used in

- subsequent <code>LogFormat</code> or <a

- href="#customlog">CustomLog</a> directives rather than

- repeating the entire format string. A <samp>LogFormat</samp>

- directive which defines a nickname <strong>does nothing

- else</strong> -- that is, it <em>only</em> defines the

- nickname, it doesn't actually apply the format and make it the

- default. Therefore, it will not affect subsequent <a

- href="#transferlog">TransferLog</a> directives.</p>

- <p>For example:</p>

- <code>LogFormat "%v %h %l %u %t \"%r\" %>s %b" vhost_common</code>

- <hr />

- <h2><a id="transferlog" name="transferlog">TransferLog</a>

- directive</h2>

- <p><a href="directive-dict.html#Syntax"

- rel="Help"><strong>Syntax:</strong></a> TransferLog

- <em>file</em>|<em>pipe</em><br />

- <a href="directive-dict.html#Default"

- rel="Help"><strong>Default:</strong></a> none<br />

- <a href="directive-dict.html#Context"

- rel="Help"><strong>Context:</strong></a> server config, virtual

- host<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_log_config</p>

- <p>This directive has exactly the same arguments and effect as

- the <a href="#customlog">CustomLog</a> directive, with the

- exception that it does not allow the log format to be specified

- explicitly or for conditional logging of requests. Instead, the

- log format is determined by the most recently specified <a

- href="#logformat">LogFormat</a> directive (that does not define

- a nickname). Common Log Format is used if no other format has

- been specified.</p>

- <p>Example:</p>

-<pre>

- LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\""

- TransferLog logs/access_log

-</pre>

- <hr />

- <h3 align="CENTER">Apache HTTP Server Version 1.3</h3>

- <a href="./"><img src="../images/index.gif" alt="Index" /></a>

- <a href="../"><img src="../images/home.gif" alt="Home" /></a>

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