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15 <p class="apache">Apache HTTP Server Version 2.1</p>
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19 <a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs-project/">Documentation</a> > <a href="./">Version 2.1</a></div><div id="page-content"><div id="preamble"><h1>Content Negotiation</h1>
21 <p><span>Available Languages: </span><a href="./en/content-negotiation.html" title="English"> en </a> |
22 <a href="./ja/content-negotiation.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
23 <a href="./ko/content-negotiation.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
27 <p>Apache supports content negotiation as described in
28 the HTTP/1.1 specification. It can choose the best
29 representation of a resource based on the browser-supplied
30 preferences for media type, languages, character set and
31 encoding. It also implements a couple of features to give
32 more intelligent handling of requests from browsers that send
33 incomplete negotiation information.</p>
35 <p>Content negotiation is provided by the
36 <code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code> module, which is compiled in
39 <div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#about">About Content Negotiation</a></li>
40 <li><img alt="" src="./images/down.gif" /> <a href="#negotiation">Negotiation in Apache</a></li>
41 <li><img alt="" src="./images/down.gif" /> <a href="#methods">The Negotiation Methods</a></li>
42 <li><img alt="" src="./images/down.gif" /> <a href="#better">Fiddling with Quality
44 <li><img alt="" src="./images/down.gif" /> <a href="#extensions">Extensions to Transparent Content
46 <li><img alt="" src="./images/down.gif" /> <a href="#naming">Note on hyperlinks and naming conventions</a></li>
47 <li><img alt="" src="./images/down.gif" /> <a href="#caching">Note on Caching</a></li>
48 <li><img alt="" src="./images/down.gif" /> <a href="#more">More Information</a></li>
50 <div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
52 <h2><a name="about" id="about">About Content Negotiation</a></h2>
54 <p>A resource may be available in several different
55 representations. For example, it might be available in
56 different languages or different media types, or a combination.
57 One way of selecting the most appropriate choice is to give the
58 user an index page, and let them select. However it is often
59 possible for the server to choose automatically. This works
60 because browsers can send, as part of each request, information
61 about what representations they prefer. For example, a browser
62 could indicate that it would like to see information in French,
63 if possible, else English will do. Browsers indicate their
64 preferences by headers in the request. To request only French
65 representations, the browser would send</p>
67 <div class="example"><p><code>Accept-Language: fr</code></p></div>
69 <p>Note that this preference will only be applied when there is
70 a choice of representations and they vary by language.</p>
72 <p>As an example of a more complex request, this browser has
73 been configured to accept French and English, but prefer
74 French, and to accept various media types, preferring HTML over
75 plain text or other text types, and preferring GIF or JPEG over
76 other media types, but also allowing any other media type as a
79 <div class="example"><p><code>
80 Accept-Language: fr; q=1.0, en; q=0.5<br />
81 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
84 <p>Apache supports 'server driven' content negotiation, as
85 defined in the HTTP/1.1 specification. It fully supports the
86 <code>Accept</code>, <code>Accept-Language</code>,
87 <code>Accept-Charset</code> and<code>Accept-Encoding</code>
88 request headers. Apache also supports 'transparent'
89 content negotiation, which is an experimental negotiation
90 protocol defined in RFC 2295 and RFC 2296. It does not offer
91 support for 'feature negotiation' as defined in these RFCs.</p>
93 <p>A <strong>resource</strong> is a conceptual entity
94 identified by a URI (RFC 2396). An HTTP server like Apache
95 provides access to <strong>representations</strong> of the
96 resource(s) within its namespace, with each representation in
97 the form of a sequence of bytes with a defined media type,
98 character set, encoding, etc. Each resource may be associated
99 with zero, one, or more than one representation at any given
100 time. If multiple representations are available, the resource
101 is referred to as <strong>negotiable</strong> and each of its
102 representations is termed a <strong>variant</strong>. The ways
103 in which the variants for a negotiable resource vary are called
104 the <strong>dimensions</strong> of negotiation.</p>
105 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
106 <div class="section">
107 <h2><a name="negotiation" id="negotiation">Negotiation in Apache</a></h2>
109 <p>In order to negotiate a resource, the server needs to be
110 given information about each of the variants. This is done in
114 <li>Using a type map (<em>i.e.</em>, a <code>*.var</code>
115 file) which names the files containing the variants
118 <li>Using a 'MultiViews' search, where the server does an
119 implicit filename pattern match and chooses from among the
123 <h3><a name="type-map" id="type-map">Using a type-map file</a></h3>
125 <p>A type map is a document which is associated with the
126 handler named <code>type-map</code> (or, for
127 backwards-compatibility with older Apache configurations, the
128 MIME type <code>application/x-type-map</code>). Note that to
129 use this feature, you must have a handler set in the
130 configuration that defines a file suffix as
131 <code>type-map</code>; this is best done with</p>
133 <div class="example"><p><code>AddHandler type-map .var</code></p></div>
135 <p>in the server configuration file.</p>
137 <p>Type map files should have the same name as the resource
138 which they are describing, and have an entry for each available
139 variant; these entries consist of contiguous HTTP-format header
140 lines. Entries for different variants are separated by blank
141 lines. Blank lines are illegal within an entry. It is
142 conventional to begin a map file with an entry for the combined
143 entity as a whole (although this is not required, and if
144 present will be ignored). An example map file is shown below.
145 This file would be named <code>foo.var</code>, as it describes
146 a resource named <code>foo</code>.</p>
148 <div class="example"><p><code>
151 URI: foo.en.html<br />
152 Content-type: text/html<br />
153 Content-language: en<br />
155 URI: foo.fr.de.html<br />
156 Content-type: text/html;charset=iso-8859-2<br />
157 Content-language: fr, de<br />
159 <p>Note also that a typemap file will take precedence over the
160 filename's extension, even when Multiviews is on. If the
161 variants have different source qualities, that may be indicated
162 by the "qs" parameter to the media type, as in this picture
163 (available as JPEG, GIF, or ASCII-art): </p>
165 <div class="example"><p><code>
169 Content-type: image/jpeg; qs=0.8<br />
172 Content-type: image/gif; qs=0.5<br />
175 Content-type: text/plain; qs=0.01<br />
178 <p>qs values can vary in the range 0.000 to 1.000. Note that
179 any variant with a qs value of 0.000 will never be chosen.
180 Variants with no 'qs' parameter value are given a qs factor of
181 1.0. The qs parameter indicates the relative 'quality' of this
182 variant compared to the other available variants, independent
183 of the client's capabilities. For example, a JPEG file is
184 usually of higher source quality than an ASCII file if it is
185 attempting to represent a photograph. However, if the resource
186 being represented is an original ASCII art, then an ASCII
187 representation would have a higher source quality than a JPEG
188 representation. A qs value is therefore specific to a given
189 variant depending on the nature of the resource it
192 <p>The full list of headers recognized is available in the <a href="mod/mod_negotiation.html#typemaps">mod_negotation
193 typemap</a> documentation.</p>
196 <h3><a name="multiviews" id="multiviews">Multiviews</a></h3>
198 <p><code>MultiViews</code> is a per-directory option, meaning it
199 can be set with an <code class="directive"><a href="./mod/core.html#options">Options</a></code>
200 directive within a <code class="directive"><a href="./mod/core.html#directory"><Directory></a></code>, <code class="directive"><a href="./mod/core.html#location"><Location></a></code> or <code class="directive"><a href="./mod/core.html#files"><Files></a></code> section in
201 <code>httpd.conf</code>, or (if <code class="directive"><a href="./mod/core.html#allowoverride">AllowOverride</a></code> is properly set) in
202 <code>.htaccess</code> files. Note that <code>Options All</code>
203 does not set <code>MultiViews</code>; you have to ask for it by
206 <p>The effect of <code>MultiViews</code> is as follows: if the
207 server receives a request for <code>/some/dir/foo</code>, if
208 <code>/some/dir</code> has <code>MultiViews</code> enabled, and
209 <code>/some/dir/foo</code> does <em>not</em> exist, then the
210 server reads the directory looking for files named foo.*, and
211 effectively fakes up a type map which names all those files,
212 assigning them the same media types and content-encodings it
213 would have if the client had asked for one of them by name. It
214 then chooses the best match to the client's requirements.</p>
216 <p><code>MultiViews</code> may also apply to searches for the file
217 named by the <code class="directive"><a href="./mod/mod_dir.html#directoryindex">DirectoryIndex</a></code> directive, if the
218 server is trying to index a directory. If the configuration files
220 <div class="example"><p><code>DirectoryIndex index</code></p></div>
221 <p>then the server will arbitrate between <code>index.html</code>
222 and <code>index.html3</code> if both are present. If neither
223 are present, and <code>index.cgi</code> is there, the server
226 <p>If one of the files found when reading the directory does not
227 have an extension recognized by <code>mod_mime</code> to designate
228 its Charset, Content-Type, Language, or Encoding, then the result
229 depends on the setting of the <code class="directive"><a href="./mod/mod_mime.html#multiviewsmatch">MultiViewsMatch</a></code> directive. This
230 directive determines whether handlers, filters, and other
231 extension types can participate in MultiViews negotiation.</p>
233 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
234 <div class="section">
235 <h2><a name="methods" id="methods">The Negotiation Methods</a></h2>
237 <p>After Apache has obtained a list of the variants for a given
238 resource, either from a type-map file or from the filenames in
239 the directory, it invokes one of two methods to decide on the
240 'best' variant to return, if any. It is not necessary to know
241 any of the details of how negotiation actually takes place in
242 order to use Apache's content negotiation features. However the
243 rest of this document explains the methods used for those
246 <p>There are two negotiation methods:</p>
249 <li><strong>Server driven negotiation with the Apache
250 algorithm</strong> is used in the normal case. The Apache
251 algorithm is explained in more detail below. When this
252 algorithm is used, Apache can sometimes 'fiddle' the quality
253 factor of a particular dimension to achieve a better result.
254 The ways Apache can fiddle quality factors is explained in
255 more detail below.</li>
257 <li><strong>Transparent content negotiation</strong> is used
258 when the browser specifically requests this through the
259 mechanism defined in RFC 2295. This negotiation method gives
260 the browser full control over deciding on the 'best' variant,
261 the result is therefore dependent on the specific algorithms
262 used by the browser. As part of the transparent negotiation
263 process, the browser can ask Apache to run the 'remote
264 variant selection algorithm' defined in RFC 2296.</li>
267 <h3><a name="dimensions" id="dimensions">Dimensions of Negotiation</a></h3>
280 <td>Browser indicates preferences with the <code>Accept</code>
281 header field. Each item can have an associated quality factor.
282 Variant description can also have a quality factor (the "qs"
289 <td>Browser indicates preferences with the
290 <code>Accept-Language</code> header field. Each item can have
291 a quality factor. Variants can be associated with none, one or
292 more than one language.</td>
298 <td>Browser indicates preference with the
299 <code>Accept-Encoding</code> header field. Each item can have
300 a quality factor.</td>
306 <td>Browser indicates preference with the
307 <code>Accept-Charset</code> header field. Each item can have a
308 quality factor. Variants can indicate a charset as a parameter
309 of the media type.</td>
314 <h3><a name="algorithm" id="algorithm">Apache Negotiation Algorithm</a></h3>
316 <p>Apache can use the following algorithm to select the 'best'
317 variant (if any) to return to the browser. This algorithm is
318 not further configurable. It operates as follows:</p>
321 <li>First, for each dimension of the negotiation, check the
322 appropriate <em>Accept*</em> header field and assign a
323 quality to each variant. If the <em>Accept*</em> header for
324 any dimension implies that this variant is not acceptable,
325 eliminate it. If no variants remain, go to step 4.</li>
328 Select the 'best' variant by a process of elimination. Each
329 of the following tests is applied in order. Any variants
330 not selected at each test are eliminated. After each test,
331 if only one variant remains, select it as the best match
332 and proceed to step 3. If more than one variant remains,
333 move on to the next test.
336 <li>Multiply the quality factor from the <code>Accept</code>
337 header with the quality-of-source factor for this variants
338 media type, and select the variants with the highest
341 <li>Select the variants with the highest language quality
344 <li>Select the variants with the best language match,
345 using either the order of languages in the
346 <code>Accept-Language</code> header (if present), or else
347 the order of languages in the <code>LanguagePriority</code>
348 directive (if present).</li>
350 <li>Select the variants with the highest 'level' media
351 parameter (used to give the version of text/html media
354 <li>Select variants with the best charset media
355 parameters, as given on the <code>Accept-Charset</code>
356 header line. Charset ISO-8859-1 is acceptable unless
357 explicitly excluded. Variants with a <code>text/*</code>
358 media type but not explicitly associated with a particular
359 charset are assumed to be in ISO-8859-1.</li>
361 <li>Select those variants which have associated charset
362 media parameters that are <em>not</em> ISO-8859-1. If
363 there are no such variants, select all variants
366 <li>Select the variants with the best encoding. If there
367 are variants with an encoding that is acceptable to the
368 user-agent, select only these variants. Otherwise if
369 there is a mix of encoded and non-encoded variants,
370 select only the unencoded variants. If either all
371 variants are encoded or all variants are not encoded,
372 select all variants.</li>
374 <li>Select the variants with the smallest content
377 <li>Select the first variant of those remaining. This
378 will be either the first listed in the type-map file, or
379 when variants are read from the directory, the one whose
380 file name comes first when sorted using ASCII code
385 <li>The algorithm has now selected one 'best' variant, so
386 return it as the response. The HTTP response header
387 <code>Vary</code> is set to indicate the dimensions of
388 negotiation (browsers and caches can use this information when
389 caching the resource). End.</li>
391 <li>To get here means no variant was selected (because none
392 are acceptable to the browser). Return a 406 status (meaning
393 "No acceptable representation") with a response body
394 consisting of an HTML document listing the available
395 variants. Also set the HTTP <code>Vary</code> header to
396 indicate the dimensions of variance.</li>
399 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
400 <div class="section">
401 <h2><a name="better" id="better">Fiddling with Quality
404 <p>Apache sometimes changes the quality values from what would
405 be expected by a strict interpretation of the Apache
406 negotiation algorithm above. This is to get a better result
407 from the algorithm for browsers which do not send full or
408 accurate information. Some of the most popular browsers send
409 <code>Accept</code> header information which would otherwise
410 result in the selection of the wrong variant in many cases. If a
411 browser sends full and correct information these fiddles will not
414 <h3><a name="wildcards" id="wildcards">Media Types and Wildcards</a></h3>
416 <p>The <code>Accept:</code> request header indicates preferences
417 for media types. It can also include 'wildcard' media types, such
418 as "image/*" or "*/*" where the * matches any string. So a request
421 <div class="example"><p><code>Accept: image/*, */*</code></p></div>
423 <p>would indicate that any type starting "image/" is acceptable,
424 as is any other type.
425 Some browsers routinely send wildcards in addition to explicit
426 types they can handle. For example:</p>
428 <div class="example"><p><code>
429 Accept: text/html, text/plain, image/gif, image/jpeg, */*
431 <p>The intention of this is to indicate that the explicitly listed
432 types are preferred, but if a different representation is
433 available, that is ok too. Using explicit quality values,
434 what the browser really wants is something like:</p>
435 <div class="example"><p><code>
436 Accept: text/html, text/plain, image/gif, image/jpeg, */*; q=0.01
438 <p>The explicit types have no quality factor, so they default to a
439 preference of 1.0 (the highest). The wildcard */* is given a
440 low preference of 0.01, so other types will only be returned if
441 no variant matches an explicitly listed type.</p>
443 <p>If the <code>Accept:</code> header contains <em>no</em> q
444 factors at all, Apache sets the q value of "*/*", if present, to
445 0.01 to emulate the desired behavior. It also sets the q value of
446 wildcards of the format "type/*" to 0.02 (so these are preferred
447 over matches against "*/*". If any media type on the
448 <code>Accept:</code> header contains a q factor, these special
449 values are <em>not</em> applied, so requests from browsers which
450 send the explicit information to start with work as expected.</p>
453 <h3><a name="exceptions" id="exceptions">Language Negotiation Exceptions</a></h3>
455 <p>New in Apache 2.0, some exceptions have been added to the
456 negotiation algorithm to allow graceful fallback when language
457 negotiation fails to find a match.</p>
459 <p>When a client requests a page on your server, but the server
460 cannot find a single page that matches the
461 <code>Accept-language</code> sent by
462 the browser, the server will return either a "No Acceptable
463 Variant" or "Multiple Choices" response to the client. To avoid
464 these error messages, it is possible to configure Apache to ignore
465 the <code>Accept-language</code> in these cases and provide a
466 document that does not explicitly match the client's request. The
467 <code class="directive"><a href="./mod/mod_negotiation.html#forcelanguagepriority">ForceLanguagePriority</a></code>
468 directive can be used to override one or both of these error
469 messages and substitute the servers judgement in the form of the
470 <code class="directive"><a href="./mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>
473 <p>The server will also attempt to match language-subsets when no
474 other match can be found. For example, if a client requests
475 documents with the language <code>en-GB</code> for British
476 English, the server is not normally allowed by the HTTP/1.1
477 standard to match that against a document that is marked as simply
478 <code>en</code>. (Note that it is almost surely a configuration
479 error to include <code>en-GB</code> and not <code>en</code> in the
480 <code>Accept-Language</code> header, since it is very unlikely
481 that a reader understands British English, but doesn't understand
482 English in general. Unfortunately, many current clients have
483 default configurations that resemble this.) However, if no other
484 language match is possible and the server is about to return a "No
485 Acceptable Variants" error or fallback to the <code class="directive"><a href="./mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>, the server
486 will ignore the subset specification and match <code>en-GB</code>
487 against <code>en</code> documents. Implicitly, Apache will add
488 the parent language to the client's acceptable language list with
489 a very low quality value. But note that if the client requests
490 "en-GB; q=0.9, fr; q=0.8", and the server has documents
491 designated "en" and "fr", then the "fr" document will be returned.
492 This is necessary to maintain compliance with the HTTP/1.1
493 specification and to work effectively with properly configured
496 <p>In order to support advanced techniques (such as cookies or
497 special URL-paths) to determine the user's preferred language,
498 since Apache 2.0.47 <code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code> recognizes
499 the <a href="env.html">environment variable</a>
500 <code>prefer-language</code>. If it exists and contains an
501 appropriate language tag, <code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code> will
502 try to select a matching variant. If there's no such variant,
503 the normal negotiation process applies.</p>
505 <div class="example"><h3>Example</h3><p><code>
506 SetEnvIf Cookie "language=(.+)" prefer-language=$1
509 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
510 <div class="section">
511 <h2><a name="extensions" id="extensions">Extensions to Transparent Content
514 <p>Apache extends the transparent content negotiation protocol (RFC
515 2295) as follows. A new <code>{encoding ..}</code> element is used in
516 variant lists to label variants which are available with a specific
517 content-encoding only. The implementation of the RVSA/1.0 algorithm
518 (RFC 2296) is extended to recognize encoded variants in the list, and
519 to use them as candidate variants whenever their encodings are
520 acceptable according to the <code>Accept-Encoding</code> request
521 header. The RVSA/1.0 implementation does not round computed quality
522 factors to 5 decimal places before choosing the best variant.</p>
523 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
524 <div class="section">
525 <h2><a name="naming" id="naming">Note on hyperlinks and naming conventions</a></h2>
527 <p>If you are using language negotiation you can choose between
528 different naming conventions, because files can have more than
529 one extension, and the order of the extensions is normally
530 irrelevant (see the <a href="mod/mod_mime.html#multipleext">mod_mime</a> documentation
533 <p>A typical file has a MIME-type extension (<em>e.g.</em>,
534 <code>html</code>), maybe an encoding extension (<em>e.g.</em>,
535 <code>gz</code>), and of course a language extension
536 (<em>e.g.</em>, <code>en</code>) when we have different
537 language variants of this file.</p>
546 <li>foo.en.html.gz</li>
549 <p>Here some more examples of filenames together with valid and
550 invalid hyperlinks:</p>
552 <table class="bordered">
557 <th>Valid hyperlink</th>
559 <th>Invalid hyperlink</th>
563 <td><em>foo.html.en</em></td>
572 <td><em>foo.en.html</em></td>
580 <td><em>foo.html.en.gz</em></td>
590 <td><em>foo.en.html.gz</em></td>
600 <td><em>foo.gz.html.en</em></td>
610 <td><em>foo.html.gz.en</em></td>
620 <p>Looking at the table above, you will notice that it is always
621 possible to use the name without any extensions in a hyperlink
622 (<em>e.g.</em>, <code>foo</code>). The advantage is that you
623 can hide the actual type of a document rsp. file and can change
624 it later, <em>e.g.</em>, from <code>html</code> to
625 <code>shtml</code> or <code>cgi</code> without changing any
626 hyperlink references.</p>
628 <p>If you want to continue to use a MIME-type in your
629 hyperlinks (<em>e.g.</em> <code>foo.html</code>) the language
630 extension (including an encoding extension if there is one)
631 must be on the right hand side of the MIME-type extension
632 (<em>e.g.</em>, <code>foo.html.en</code>).</p>
633 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
634 <div class="section">
635 <h2><a name="caching" id="caching">Note on Caching</a></h2>
637 <p>When a cache stores a representation, it associates it with
638 the request URL. The next time that URL is requested, the cache
639 can use the stored representation. But, if the resource is
640 negotiable at the server, this might result in only the first
641 requested variant being cached and subsequent cache hits might
642 return the wrong response. To prevent this, Apache normally
643 marks all responses that are returned after content negotiation
644 as non-cacheable by HTTP/1.0 clients. Apache also supports the
645 HTTP/1.1 protocol features to allow caching of negotiated
648 <p>For requests which come from a HTTP/1.0 compliant client
649 (either a browser or a cache), the directive <code class="directive"><a href="./mod/mod_negotiation.html#cachenegotiateddocs">CacheNegotiatedDocs</a></code> can be
650 used to allow caching of responses which were subject to
651 negotiation. This directive can be given in the server config or
652 virtual host, and takes no arguments. It has no effect on requests
653 from HTTP/1.1 clients.</p>
655 <p>For HTTP/1.1 clients, Apache sends a <code>Vary</code> HTTP
656 response header to indicate the negotiation dimensions for the
657 response. Caches can use this information to determine whether a
658 subsequent request can be served from the local copy. To
659 encourage a cache to use the local copy regardless of the
660 negotiation dimensions, set the <code>force-no-vary</code> <a href="env.html#special">environment variable</a>.</p>
662 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
663 <div class="section">
664 <h2><a name="more" id="more">More Information</a></h2>
666 <p>For more information about content negotiation, see Alan
667 J. Flavell's <a href="http://ppewww.ph.gla.ac.uk/~flavell/www/lang-neg.html">Language
668 Negotiation Notes</a>. But note that this document may not be
669 updated to include changes in Apache 2.0.</p>
671 <div class="bottomlang">
672 <p><span>Available Languages: </span><a href="./en/content-negotiation.html" title="English"> en </a> |
673 <a href="./ja/content-negotiation.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
674 <a href="./ko/content-negotiation.html" hreflang="ko" rel="alternate" title="Korean"> ko </a></p>
675 </div><div id="footer">
676 <p class="apache">Copyright 1995-2005 The Apache Software Foundation or its licensors, as applicable.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
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