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  10 <title>mod_deflate - Apache HTTP Server Version 2.5</title>
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  20 <p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/quickreference.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
  21 <p class="apache">Apache HTTP Server Version 2.5</p>
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  25 <a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="../">Version 2.5</a> &gt; <a href="./">Modules</a></div>
  26 <div id="page-content">
  27 <div id="preamble"><h1>Apache Module mod_deflate</h1>
  28 <div class="toplang">
  29 <p><span>Available Languages: </span><a href="../en/mod/mod_deflate.html" title="English">&nbsp;en&nbsp;</a> |
  30 <a href="../fr/mod/mod_deflate.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a> |
  31 <a href="../ja/mod/mod_deflate.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
  32 <a href="../ko/mod/mod_deflate.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
  33 </div>
  34 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Compress content before it is delivered to the
  35 client</td></tr>
  36 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
  37 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>deflate_module</td></tr>
  38 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_deflate.c</td></tr></table>
  39 <h3>Summary</h3>
  40
  41     <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module provides
  42     the <code>DEFLATE</code> output filter that allows output from
  43     your server to be compressed before being sent to the client over
  44     the network.</p>
  45 </div>
  46 <div id="quickview"><h3>Topics</h3>
  47 <ul id="topics">
  48 <li><img alt="" src="../images/down.gif" /> <a href="#supportedencodings">Supported Encodings</a></li>
  49 <li><img alt="" src="../images/down.gif" /> <a href="#recommended">Sample Configurations</a></li>
  50 <li><img alt="" src="../images/down.gif" /> <a href="#enable">Enabling Compression</a></li>
  51 <li><img alt="" src="../images/down.gif" /> <a href="#proxies">Dealing with proxy servers</a></li>
  52 <li><img alt="" src="../images/down.gif" /> <a href="#precompressed">Serving pre-compressed
  53 content</a></li>
  54 </ul><h3 class="directives">Directives</h3>
  55 <ul id="toc">
  56 <li><img alt="" src="../images/down.gif" /> <a href="#deflatealteretag">DeflateAlterETag</a></li>
  57 <li><img alt="" src="../images/down.gif" /> <a href="#deflatebuffersize">DeflateBufferSize</a></li>
  58 <li><img alt="" src="../images/down.gif" /> <a href="#deflatecompressionlevel">DeflateCompressionLevel</a></li>
  59 <li><img alt="" src="../images/down.gif" /> <a href="#deflatefilternote">DeflateFilterNote</a></li>
  60 <li><img alt="" src="../images/down.gif" /> <a href="#deflateinflatelimitrequestbody">DeflateInflateLimitRequestBody</a></li>
  61 <li><img alt="" src="../images/down.gif" /> <a href="#deflateinflateratioburst">DeflateInflateRatioBurst</a></li>
  62 <li><img alt="" src="../images/down.gif" /> <a href="#deflateinflateratiolimit">DeflateInflateRatioLimit</a></li>
  63 <li><img alt="" src="../images/down.gif" /> <a href="#deflatememlevel">DeflateMemLevel</a></li>
  64 <li><img alt="" src="../images/down.gif" /> <a href="#deflatewindowsize">DeflateWindowSize</a></li>
  65 </ul>
  66 <h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&amp;list_id=144532&amp;product=Apache%20httpd-2&amp;query_format=specific&amp;order=changeddate%20DESC%2Cpriority%2Cbug_severity&amp;component=mod_deflate">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&amp;component=mod_deflate">Report a bug</a></li></ul><h3>See also</h3>
  67 <ul class="seealso">
  68 <li><a href="../filter.html">Filters</a></li>
  69 <li><a href="#comments_section">Comments</a></li></ul></div>
  70 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
  71 <div class="section">
  72 <h2><a name="supportedencodings" id="supportedencodings">Supported Encodings</a></h2>
  73   <p>The <code>gzip</code> encoding is the only one supported to ensure complete compatibility
  74   with old browser implementations. The <code>deflate</code> encoding is not supported,
  75   please check the <a href="http://www.gzip.org/zlib/zlib_faq.html#faq38">zlib's documentation</a>
  76   for a complete explanation.
  77   </p>
  78 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
  79 <div class="section">
  80 <h2><a name="recommended" id="recommended">Sample Configurations</a></h2>
  81     <div class="warning"><h3>Compression and TLS</h3>
  82         <p>Some web applications are vulnerable to an information disclosure
  83         attack when a TLS connection carries deflate compressed data. For more
  84         information, review the details of the "BREACH" family of attacks.</p>
  85     </div>
  86     <p>This is a simple configuration that compresses common text-based content types.</p>
  87
  88     <div class="example"><h3>Compress only a few types</h3><pre class="prettyprint lang-config">AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css text/javascript application/javascript</pre>
  89 </div>
  90
  91 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
  92 <div class="section">
  93 <h2><a name="enable" id="enable">Enabling Compression</a></h2>
  94     <div class="warning"><h3>Compression and TLS</h3>
  95         <p>Some web applications are vulnerable to an information disclosure
  96         attack when a TLS connection carries deflate compressed data. For more
  97         information, review the details of the "BREACH" family of attacks.</p>
  98     </div>
  99
 100     <h3><a name="output" id="output">Output Compression</a></h3>
 101       <p>Compression is implemented by the <code>DEFLATE</code>
 102       <a href="../filter.html">filter</a>. The following directive
 103       will enable compression for documents in the container where it
 104       is placed:</p>
 105
 106       <pre class="prettyprint lang-config">SetOutputFilter DEFLATE
 107 SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip</pre>
 108
 109
 110       <p>If you want to restrict the compression to particular MIME types
 111       in general, you may use the <code class="directive"><a href="../mod/mod_filter.html#addoutputfilterbytype">AddOutputFilterByType</a></code> directive. Here is an example of
 112       enabling compression only for the html files of the Apache
 113       documentation:</p>
 114
 115       <pre class="prettyprint lang-config">&lt;Directory "/your-server-root/manual"&gt;
 116     AddOutputFilterByType DEFLATE text/html
 117 &lt;/Directory&gt;</pre>
 118
 119
 120       <div class="note"><h3>Note</h3>
 121         The <code>DEFLATE</code> filter is always inserted after RESOURCE
 122         filters like PHP or SSI. It never touches internal subrequests.
 123       </div>
 124       <div class="note"><h3>Note</h3>
 125         There is an environment variable <code>force-gzip</code>,
 126         set via <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code>, which
 127         will ignore the accept-encoding setting of your browser and will
 128         send compressed output.
 129       </div>
 130
 131
 132     <h3><a name="inflate" id="inflate">Output Decompression</a></h3>
 133       <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module also provides a filter for
 134       inflating/uncompressing a gzip compressed response body. In order to activate
 135       this feature you have to insert the <code>INFLATE</code> filter into
 136       the output filter chain using <code class="directive"><a href="../mod/core.html#setoutputfilter">SetOutputFilter</a></code> or <code class="directive"><a href="../mod/mod_mime.html#addoutputfilter">AddOutputFilter</a></code>, for example:</p>
 137
 138       <pre class="prettyprint lang-config">&lt;Location "/dav-area"&gt;
 139     ProxyPass "http://example.com/"
 140     SetOutputFilter INFLATE
 141 &lt;/Location&gt;</pre>
 142
 143
 144       <p>This Example will uncompress gzip'ed output from example.com, so other
 145       filters can do further processing with it.
 146       </p>
 147
 148
 149     <h3><a name="input" id="input">Input Decompression</a></h3>
 150       <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module also provides a filter for
 151       decompressing a gzip compressed request body . In order to activate
 152       this feature you have to insert the <code>DEFLATE</code> filter into
 153       the input filter chain using <code class="directive"><a href="../mod/core.html#setinputfilter">SetInputFilter</a></code> or <code class="directive"><a href="../mod/mod_mime.html#addinputfilter">AddInputFilter</a></code>, for example:</p>
 154
 155       <pre class="prettyprint lang-config">&lt;Location "/dav-area"&gt;
 156     SetInputFilter DEFLATE
 157 &lt;/Location&gt;</pre>
 158
 159
 160       <p>Now if a request contains a <code>Content-Encoding:
 161       gzip</code> header, the body will be automatically decompressed.
 162       Few browsers have the ability to gzip request bodies. However,
 163       some special applications actually do support request
 164       compression, for instance some <a href="http://www.webdav.org">WebDAV</a> clients.</p>
 165
 166       <div class="warning"><h3>Note on Content-Length</h3>
 167         <p>If you evaluate the request body yourself, <em>don't trust
 168         the <code>Content-Length</code> header!</em>
 169         The Content-Length header reflects the length of the
 170         incoming data from the client and <em>not</em> the byte count of
 171         the decompressed data stream.</p>
 172       </div>
 173
 174 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 175 <div class="section">
 176 <h2><a name="proxies" id="proxies">Dealing with proxy servers</a></h2>
 177
 178     <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module sends a <code>Vary:
 179     Accept-Encoding</code> HTTP response header to alert proxies that
 180     a cached response should be sent only to clients that send the
 181     appropriate <code>Accept-Encoding</code> request header.  This
 182     prevents compressed content from being sent to a client that will
 183     not understand it.</p>
 184
 185     <p>If you use some special exclusions dependent
 186     on, for example, the <code>User-Agent</code> header, you must
 187     manually configure an addition to the <code>Vary</code> header
 188     to alert proxies of the additional restrictions.  For example,
 189     in a typical configuration where the addition of the <code>DEFLATE</code>
 190     filter depends on the <code>User-Agent</code>, you should add:</p>
 191
 192     <pre class="prettyprint lang-config">Header append Vary User-Agent</pre>
 193
 194
 195     <p>If your decision about compression depends on other information
 196     than request headers (<em>e.g.</em> HTTP version), you have to set the
 197     <code>Vary</code> header to the value <code>*</code>. This prevents
 198     compliant proxies from caching entirely.</p>
 199
 200     <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">Header set Vary *</pre>
 201 </div>
 202 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 203 <div class="section">
 204 <h2><a name="precompressed" id="precompressed">Serving pre-compressed
 205 content</a></h2>
 206
 207     <p>Since <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> re-compresses content each
 208     time a request is made, some performance benefit can be derived by
 209     pre-compressing the content and telling mod_deflate to serve them
 210     without re-compressing them. This may be accomplished using a
 211     configuration like the following:</p>
 212
 213     <pre class="prettyprint lang-config">&lt;IfModule mod_headers.c&gt;
 214     # Serve gzip compressed CSS files if they exist
 215     # and the client accepts gzip.
 216     RewriteCond "%{HTTP:Accept-encoding}" "gzip"
 217     RewriteCond "%{REQUEST_FILENAME}\.gz" "-s"
 218     RewriteRule "^(.*)\.css"              "$1\.css\.gz" [QSA]
 219
 220     # Serve gzip compressed JS files if they exist
 221     # and the client accepts gzip.
 222     RewriteCond "%{HTTP:Accept-encoding}" "gzip"
 223     RewriteCond "%{REQUEST_FILENAME}\.gz" "-s"
 224     RewriteRule "^(.*)\.js"               "$1\.js\.gz" [QSA]
 225
 226
 227     # Serve correct content types, and prevent mod_deflate double gzip.
 228     RewriteRule "\.css\.gz$" "-" [T=text/css,E=no-gzip:1]
 229     RewriteRule "\.js\.gz$"  "-" [T=text/javascript,E=no-gzip:1]
 230
 231
 232     &lt;FilesMatch "(\.js\.gz|\.css\.gz)$"&gt;
 233       # Serve correct encoding type.
 234       Header append Content-Encoding gzip
 235
 236       # Force proxies to cache gzipped &amp;
 237       # non-gzipped css/js files separately.
 238       Header append Vary Accept-Encoding
 239     &lt;/FilesMatch&gt;
 240 &lt;/IfModule&gt;</pre>
 241
 242
 243 </div>
 244 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 245 <div class="directive-section"><h2><a name="DeflateAlterETag" id="DeflateAlterETag">DeflateAlterETag</a> <a name="deflatealteretag" id="deflatealteretag">Directive</a></h2>
 246 <table class="directive">
 247 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How the outgoing ETag header should be modified during compression</td></tr>
 248 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateAlterETag AddSuffix|NoChange|Remove</code></td></tr>
 249 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateAlterETag AddSuffix</code></td></tr>
 250 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 251 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 252 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 253 </table>
 254     <p>The <code class="directive">DeflateAlterETag</code> directive specifies
 255     how the ETag hader should be altered when a response is compressed.</p>
 256     <dl>
 257     <dt>AddSuffix</dt>
 258     <dd><p>Append the compression method onto the end of the ETag, causing
 259         compressed and uncompressed representations to have unique ETags.
 260         This has been the default since 2.4.0, but prevents serving
 261         "HTTP Not Modified" (304) responses to conditional requests for
 262         compressed content.</p></dd>
 263     <dt>NoChange</dt>
 264     <dd><p>Don't change the ETag on a compressed response. This was the default
 265         prior to 2.4.0, but does not satisfy the HTTP/1.1 property that all
 266         representations of the same resource have unique ETags. </p></dd>
 267     <dt>Remove</dt>
 268     <dd><p>Remove the ETag header from compressed responses. This prevents
 269         some conditional requests from being possible, but avoids the
 270         shortcomings of the preceding options.  </p></dd>
 271     </dl>
 272
 273 </div>
 274 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 275 <div class="directive-section"><h2><a name="DeflateBufferSize" id="DeflateBufferSize">DeflateBufferSize</a> <a name="deflatebuffersize" id="deflatebuffersize">Directive</a></h2>
 276 <table class="directive">
 277 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Fragment size to be compressed at one time by zlib</td></tr>
 278 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateBufferSize <var>value</var></code></td></tr>
 279 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateBufferSize 8096</code></td></tr>
 280 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 281 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 282 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 283 </table>
 284     <p>The <code class="directive">DeflateBufferSize</code> directive specifies
 285     the size in bytes of the fragments that zlib should compress at one
 286     time. If the compressed response size is bigger than the one specified
 287     by this directive then httpd will switch to chunked encoding
 288     (HTTP header <code>Transfer-Encoding</code> set to <code>Chunked</code>), with the
 289     side effect of not setting any <code>Content-Length</code> HTTP header. This is particularly
 290     important when httpd works behind reverse caching proxies or when httpd is configured with
 291     <code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code> and <code class="module"><a href="../mod/mod_cache_disk.html">mod_cache_disk</a></code> because
 292     HTTP responses without any <code>Content-Length</code> header might not be cached.
 293   </p>
 294
 295 </div>
 296 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 297 <div class="directive-section"><h2><a name="DeflateCompressionLevel" id="DeflateCompressionLevel">DeflateCompressionLevel</a> <a name="deflatecompressionlevel" id="deflatecompressionlevel">Directive</a></h2>
 298 <table class="directive">
 299 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How much compression do we apply to the output</td></tr>
 300 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateCompressionLevel <var>value</var></code></td></tr>
 301 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Zlib's default</code></td></tr>
 302 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 303 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 304 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 305 </table>
 306     <p>The <code class="directive">DeflateCompressionLevel</code> directive specifies
 307         what level of compression should be used, the higher the value,
 308         the better the compression, but the more CPU time is required to
 309         achieve this.</p>
 310     <p>The value must between 1 (less compression) and 9 (more compression).</p>
 311
 312 </div>
 313 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 314 <div class="directive-section"><h2><a name="DeflateFilterNote" id="DeflateFilterNote">DeflateFilterNote</a> <a name="deflatefilternote" id="deflatefilternote">Directive</a></h2>
 315 <table class="directive">
 316 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Places the compression ratio in a note for logging</td></tr>
 317 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateFilterNote [<var>type</var>] <var>notename</var></code></td></tr>
 318 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 319 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 320 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 321 </table>
 322     <p>The <code class="directive">DeflateFilterNote</code> directive
 323     specifies that a note about compression ratios should be attached
 324     to the request. The name of the note is the value specified for
 325     the directive. You can use that note for statistical purposes by
 326     adding the value to your <a href="../logs.html#accesslog">access log</a>.</p>
 327
 328     <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">      DeflateFilterNote ratio
 329
 330       LogFormat '"%r" %b (%{ratio}n) "%{User-agent}i"' deflate
 331       CustomLog "logs/deflate_log" deflate</pre>
 332 </div>
 333
 334     <p>If you want to extract more accurate values from your logs, you
 335     can use the <var>type</var> argument to specify the type of data
 336     left as a note for logging. <var>type</var> can be one of:</p>
 337
 338     <dl>
 339       <dt><code>Input</code></dt>
 340       <dd>Store the byte count of the filter's input stream in the note.</dd>
 341
 342       <dt><code>Output</code></dt>
 343       <dd>Store the byte count of the filter's output stream in the note.</dd>
 344
 345       <dt><code>Ratio</code></dt>
 346       <dd>Store the compression ratio (<code>output/input * 100</code>)
 347       in the note. This is the default, if the <var>type</var> argument
 348       is omitted.</dd>
 349     </dl>
 350
 351     <p>Thus you may log it this way:</p>
 352
 353     <div class="example"><h3>Accurate Logging</h3><pre class="prettyprint lang-config">DeflateFilterNote Input instream
 354 DeflateFilterNote Output outstream
 355 DeflateFilterNote Ratio ratio
 356
 357 LogFormat '"%r" %{outstream}n/%{instream}n (%{ratio}n%%)' deflate
 358 CustomLog "logs/deflate_log" deflate</pre>
 359 </div>
 360
 361 <h3>See also</h3>
 362 <ul>
 363 <li><code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code></li>
 364 </ul>
 365 </div>
 366 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 367 <div class="directive-section"><h2><a name="DeflateInflateLimitRequestBody" id="DeflateInflateLimitRequestBody">DeflateInflateLimitRequestBody</a> <a name="deflateinflatelimitrequestbody" id="deflateinflatelimitrequestbody">Directive</a></h2>
 368 <table class="directive">
 369 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum size of inflated request bodies</td></tr>
 370 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateLimitRequestBody<var>value</var></code></td></tr>
 371 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>None, but LimitRequestBody applies after deflation</code></td></tr>
 372 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 373 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 374 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 375 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 376 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
 377 </table>
 378     <p>The <code class="directive">DeflateInflateLimitRequestBody</code> directive
 379         specifies the maximum size of an inflated request body. If it is unset,
 380         <code class="directive"><a href="../mod/core.html#limitrequestbody">LimitRequestBody</a></code> is applied to the
 381         inflated body.</p>
 382
 383 </div>
 384 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 385 <div class="directive-section"><h2><a name="DeflateInflateRatioBurst" id="DeflateInflateRatioBurst">DeflateInflateRatioBurst</a> <a name="deflateinflateratioburst" id="deflateinflateratioburst">Directive</a></h2>
 386 <table class="directive">
 387 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of times the inflation ratio for request bodies
 388              can be crossed</td></tr>
 389 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateRatioBurst <var>value</var></code></td></tr>
 390 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>3</code></td></tr>
 391 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 392 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 393 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 394 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 395 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
 396 </table>
 397     <p>The <code class="directive">DeflateInflateRatioBurst</code> directive
 398        specifies the maximum number of times the
 399        <code class="directive">DeflateInflateRatioLimit</code> can be crossed before
 400        terminating the request.</p>
 401
 402 </div>
 403 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 404 <div class="directive-section"><h2><a name="DeflateInflateRatioLimit" id="DeflateInflateRatioLimit">DeflateInflateRatioLimit</a> <a name="deflateinflateratiolimit" id="deflateinflateratiolimit">Directive</a></h2>
 405 <table class="directive">
 406 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum inflation ratio for request bodies</td></tr>
 407 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateRatioLimit <var>value</var></code></td></tr>
 408 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>200</code></td></tr>
 409 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 410 <tr><th><a href="directive-dict.html#Override">Override:</a></th><td>All</td></tr>
 411 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 412 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 413 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
 414 </table>
 415     <p>The <code class="directive">DeflateInflateRatioLimit</code> directive
 416         specifies the maximum ratio of deflated to inflated size of an
 417         inflated request body. This ratio is checked as the body is
 418         streamed in, and if crossed more than
 419         <code class="directive">DeflateInflateRatioBurst</code> times, the request
 420         will be terminated.</p>
 421
 422 </div>
 423 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 424 <div class="directive-section"><h2><a name="DeflateMemLevel" id="DeflateMemLevel">DeflateMemLevel</a> <a name="deflatememlevel" id="deflatememlevel">Directive</a></h2>
 425 <table class="directive">
 426 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How much memory should be used by zlib for compression</td></tr>
 427 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateMemLevel <var>value</var></code></td></tr>
 428 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateMemLevel 9</code></td></tr>
 429 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 430 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 431 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 432 </table>
 433     <p>The <code class="directive">DeflateMemLevel</code> directive specifies
 434     how much memory should be used by zlib for compression
 435     (a value between 1 and 9).</p>
 436
 437 </div>
 438 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 439 <div class="directive-section"><h2><a name="DeflateWindowSize" id="DeflateWindowSize">DeflateWindowSize</a> <a name="deflatewindowsize" id="deflatewindowsize">Directive</a></h2>
 440 <table class="directive">
 441 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Zlib compression window size</td></tr>
 442 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateWindowSize <var>value</var></code></td></tr>
 443 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateWindowSize 15</code></td></tr>
 444 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 445 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 446 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 447 </table>
 448     <p>The <code class="directive">DeflateWindowSize</code> directive specifies the
 449     zlib compression window size (a value between 1 and 15). Generally, the
 450     higher the window size, the higher can the compression ratio be expected.</p>
 451
 452 </div>
 453 </div>
 454 <div class="bottomlang">
 455 <p><span>Available Languages: </span><a href="../en/mod/mod_deflate.html" title="English">&nbsp;en&nbsp;</a> |
 456 <a href="../fr/mod/mod_deflate.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a> |
 457 <a href="../ja/mod/mod_deflate.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
 458 <a href="../ko/mod/mod_deflate.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
 459 </div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&amp;A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div>
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