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   8 <title>mod_deflate - Apache HTTP Server Version 2.5</title>
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  18 <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>
  19 <p class="apache">Apache HTTP Server Version 2.5</p>
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  23 <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>
  24 <div id="page-content">
  25 <div id="preamble"><h1>Apache Module mod_deflate</h1>
  26 <div class="toplang">
  27 <p><span>Available Languages: </span><a href="../en/mod/mod_deflate.html" title="English">&nbsp;en&nbsp;</a> |
  28 <a href="../fr/mod/mod_deflate.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a> |
  29 <a href="../ja/mod/mod_deflate.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
  30 <a href="../ko/mod/mod_deflate.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
  31 </div>
  32 <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Compress content before it is delivered to the
  33 client</td></tr>
  34 <tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
  35 <tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>deflate_module</td></tr>
  36 <tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_deflate.c</td></tr></table>
  37 <h3>Summary</h3>
  38
  39     <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module provides
  40     the <code>DEFLATE</code> output filter that allows output from
  41     your server to be compressed before being sent to the client over
  42     the network.</p>
  43 </div>
  44 <div id="quickview"><h3>Topics</h3>
  45 <ul id="topics">
  46 <li><img alt="" src="../images/down.gif" /> <a href="#recommended">Sample Configurations</a></li>
  47 <li><img alt="" src="../images/down.gif" /> <a href="#enable">Enabling Compression</a></li>
  48 <li><img alt="" src="../images/down.gif" /> <a href="#proxies">Dealing with proxy servers</a></li>
  49 <li><img alt="" src="../images/down.gif" /> <a href="#precompressed">Serving pre-compressed
  50 content</a></li>
  51 </ul><h3 class="directives">Directives</h3>
  52 <ul id="toc">
  53 <li><img alt="" src="../images/down.gif" /> <a href="#deflatealteretag">DeflateAlterETag</a></li>
  54 <li><img alt="" src="../images/down.gif" /> <a href="#deflatebuffersize">DeflateBufferSize</a></li>
  55 <li><img alt="" src="../images/down.gif" /> <a href="#deflatecompressionlevel">DeflateCompressionLevel</a></li>
  56 <li><img alt="" src="../images/down.gif" /> <a href="#deflatefilternote">DeflateFilterNote</a></li>
  57 <li><img alt="" src="../images/down.gif" /> <a href="#deflateinflatelimitrequestbody">DeflateInflateLimitRequestBody</a></li>
  58 <li><img alt="" src="../images/down.gif" /> <a href="#deflateinflateratioburst">DeflateInflateRatioBurst</a></li>
  59 <li><img alt="" src="../images/down.gif" /> <a href="#deflateinflateratiolimit">DeflateInflateRatioLimit</a></li>
  60 <li><img alt="" src="../images/down.gif" /> <a href="#deflatememlevel">DeflateMemLevel</a></li>
  61 <li><img alt="" src="../images/down.gif" /> <a href="#deflatewindowsize">DeflateWindowSize</a></li>
  62 </ul>
  63 <h3>See also</h3>
  64 <ul class="seealso">
  65 <li><a href="../filter.html">Filters</a></li>
  66 </ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div>
  67 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
  68 <div class="section">
  69 <h2><a name="recommended" id="recommended">Sample Configurations</a></h2>
  70     <div class="warning"><h3>Compression and TLS</h3>
  71         <p>Some web applications are vulnerable to an information disclosure
  72         attack when a TLS connection carries deflate compressed data. For more
  73         information, review the details of the "BREACH" family of attacks.</p>
  74     </div>
  75     <p>This is a simple configuration that compresses common text-based content types.</p>
  76
  77     <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>
  78 </div>
  79
  80 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
  81 <div class="section">
  82 <h2><a name="enable" id="enable">Enabling Compression</a></h2>
  83     <div class="warning"><h3>Compression and TLS</h3>
  84         <p>Some web applications are vulnerable to an information disclosure
  85         attack when a TLS connection carries deflate compressed data. For more
  86         information, review the details of the "BREACH" family of attacks.</p>
  87     </div>
  88
  89     <h3><a name="output" id="output">Output Compression</a></h3>
  90       <p>Compression is implemented by the <code>DEFLATE</code>
  91       <a href="../filter.html">filter</a>. The following directive
  92       will enable compression for documents in the container where it
  93       is placed:</p>
  94
  95       <pre class="prettyprint lang-config">SetOutputFilter DEFLATE
  96 SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip</pre>
  97
  98
  99       <p>If you want to restrict the compression to particular MIME types
 100       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
 101       enabling compression only for the html files of the Apache
 102       documentation:</p>
 103
 104       <pre class="prettyprint lang-config">&lt;Directory "/your-server-root/manual"&gt;
 105     AddOutputFilterByType DEFLATE text/html
 106 &lt;/Directory&gt;</pre>
 107
 108
 109       <div class="note"><h3>Note</h3>
 110         The <code>DEFLATE</code> filter is always inserted after RESOURCE
 111         filters like PHP or SSI. It never touches internal subrequests.
 112       </div>
 113       <div class="note"><h3>Note</h3>
 114         There is an environment variable <code>force-gzip</code>,
 115         set via <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code>, which
 116         will ignore the accept-encoding setting of your browser and will
 117         send compressed output.
 118       </div>
 119
 120
 121     <h3><a name="inflate" id="inflate">Output Decompression</a></h3>
 122       <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module also provides a filter for
 123       inflating/uncompressing a gzip compressed response body. In order to activate
 124       this feature you have to insert the <code>INFLATE</code> filter into
 125       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>
 126
 127       <pre class="prettyprint lang-config">&lt;Location "/dav-area"&gt;
 128     ProxyPass "http://example.com/"
 129     SetOutputFilter INFLATE
 130 &lt;/Location&gt;</pre>
 131
 132
 133       <p>This Example will uncompress gzip'ed output from example.com, so other
 134       filters can do further processing with it.
 135       </p>
 136
 137
 138     <h3><a name="input" id="input">Input Decompression</a></h3>
 139       <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module also provides a filter for
 140       decompressing a gzip compressed request body . In order to activate
 141       this feature you have to insert the <code>DEFLATE</code> filter into
 142       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>
 143
 144       <pre class="prettyprint lang-config">&lt;Location "/dav-area"&gt;
 145     SetInputFilter DEFLATE
 146 &lt;/Location&gt;</pre>
 147
 148
 149       <p>Now if a request contains a <code>Content-Encoding:
 150       gzip</code> header, the body will be automatically decompressed.
 151       Few browsers have the ability to gzip request bodies. However,
 152       some special applications actually do support request
 153       compression, for instance some <a href="http://www.webdav.org">WebDAV</a> clients.</p>
 154
 155       <div class="warning"><h3>Note on Content-Length</h3>
 156         <p>If you evaluate the request body yourself, <em>don't trust
 157         the <code>Content-Length</code> header!</em>
 158         The Content-Length header reflects the length of the
 159         incoming data from the client and <em>not</em> the byte count of
 160         the decompressed data stream.</p>
 161       </div>
 162
 163 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 164 <div class="section">
 165 <h2><a name="proxies" id="proxies">Dealing with proxy servers</a></h2>
 166
 167     <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module sends a <code>Vary:
 168     Accept-Encoding</code> HTTP response header to alert proxies that
 169     a cached response should be sent only to clients that send the
 170     appropriate <code>Accept-Encoding</code> request header.  This
 171     prevents compressed content from being sent to a client that will
 172     not understand it.</p>
 173
 174     <p>If you use some special exclusions dependent
 175     on, for example, the <code>User-Agent</code> header, you must
 176     manually configure an addition to the <code>Vary</code> header
 177     to alert proxies of the additional restrictions.  For example,
 178     in a typical configuration where the addition of the <code>DEFLATE</code>
 179     filter depends on the <code>User-Agent</code>, you should add:</p>
 180
 181     <pre class="prettyprint lang-config">Header append Vary User-Agent</pre>
 182
 183
 184     <p>If your decision about compression depends on other information
 185     than request headers (<em>e.g.</em> HTTP version), you have to set the
 186     <code>Vary</code> header to the value <code>*</code>. This prevents
 187     compliant proxies from caching entirely.</p>
 188
 189     <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">Header set Vary *</pre>
 190 </div>
 191 </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 192 <div class="section">
 193 <h2><a name="precompressed" id="precompressed">Serving pre-compressed
 194 content</a></h2>
 195
 196     <p>Since <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> re-compresses content each
 197     time a request is made, some performance benefit can be derived by
 198     pre-compressing the content and telling mod_deflate to serve them
 199     without re-compressing them. This may be accomplished using a
 200     configuration like the following:</p>
 201
 202     <pre class="prettyprint lang-config">&lt;IfModule mod_headers.c&gt;
 203     # Serve gzip compressed CSS files if they exist
 204     # and the client accepts gzip.
 205     RewriteCond %{HTTP:Accept-encoding} gzip
 206     RewriteCond %{REQUEST_FILENAME}\.gz -s
 207     RewriteRule ^(.*)\.css $1\.css\.gz [QSA]
 208
 209     # Serve gzip compressed JS files if they exist
 210     # and the client accepts gzip.
 211     RewriteCond %{HTTP:Accept-encoding} gzip
 212     RewriteCond %{REQUEST_FILENAME}\.gz -s
 213     RewriteRule ^(.*)\.js $1\.js\.gz [QSA]
 214
 215
 216     # Serve correct content types, and prevent mod_deflate double gzip.
 217     RewriteRule \.css\.gz$ - [T=text/css,E=no-gzip:1]
 218     RewriteRule \.js\.gz$ - [T=text/javascript,E=no-gzip:1]
 219
 220
 221     &lt;FilesMatch "(\.js\.gz|\.css\.gz)$"&gt;
 222       # Serve correct encoding type.
 223       Header append Content-Encoding gzip
 224
 225       # Force proxies to cache gzipped &amp;
 226       # non-gzipped css/js files separately.
 227       Header append Vary Accept-Encoding
 228     &lt;/FilesMatch&gt;
 229 &lt;/IfModule&gt;</pre>
 230
 231
 232 </div>
 233 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 234 <div class="directive-section"><h2><a name="DeflateAlterETag" id="DeflateAlterETag">DeflateAlterETag</a> <a name="deflatealteretag" id="deflatealteretag">Directive</a></h2>
 235 <table class="directive">
 236 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How the outgoing ETag header should be modified during compression</td></tr>
 237 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateAlterETag AddSuffix|NoChange|Remove</code></td></tr>
 238 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateAlterETag AddSuffix</code></td></tr>
 239 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 240 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 241 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 242 </table>
 243     <p>The <code class="directive">DeflateAlterETag</code> directive specifies
 244     how the ETag hader should be altered when a response is compressed.</p>
 245     <dl>
 246     <dt>AddSuffix</dt>
 247     <dd><p>Append the compression method onto the end of the ETag, causing
 248         compressed and uncompressed representations to have unique ETags.
 249         This has been the default since 2.4.0, but prevents serving
 250         "HTTP Not Modified" (304) responses to conditional requests for
 251         compressed content.</p></dd>
 252     <dt>NoChange</dt>
 253     <dd><p>Don't change the ETag on a compressed response. This was the default
 254         prior to 2.4.0, but does not satisfy the HTTP/1.1 property that all
 255         representations of the same resource have unique ETags. </p></dd>
 256     <dt>Remove</dt>
 257     <dd><p>Remove the ETag header from compressed responses. This prevents
 258         some conditional requests from being possible, but avoids the
 259         shortcomings of the preceding options.  </p></dd>
 260     </dl>
 261
 262 </div>
 263 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 264 <div class="directive-section"><h2><a name="DeflateBufferSize" id="DeflateBufferSize">DeflateBufferSize</a> <a name="deflatebuffersize" id="deflatebuffersize">Directive</a></h2>
 265 <table class="directive">
 266 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Fragment size to be compressed at one time by zlib</td></tr>
 267 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateBufferSize <var>value</var></code></td></tr>
 268 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateBufferSize 8096</code></td></tr>
 269 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 270 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 271 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 272 </table>
 273     <p>The <code class="directive">DeflateBufferSize</code> directive specifies
 274     the size in bytes of the fragments that zlib should compress at one
 275     time.</p>
 276
 277 </div>
 278 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 279 <div class="directive-section"><h2><a name="DeflateCompressionLevel" id="DeflateCompressionLevel">DeflateCompressionLevel</a> <a name="deflatecompressionlevel" id="deflatecompressionlevel">Directive</a></h2>
 280 <table class="directive">
 281 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How much compression do we apply to the output</td></tr>
 282 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateCompressionLevel <var>value</var></code></td></tr>
 283 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Zlib's default</code></td></tr>
 284 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 285 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 286 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 287 </table>
 288     <p>The <code class="directive">DeflateCompressionLevel</code> directive specifies
 289         what level of compression should be used, the higher the value,
 290         the better the compression, but the more CPU time is required to
 291         achieve this.</p>
 292     <p>The value must between 1 (less compression) and 9 (more compression).</p>
 293
 294 </div>
 295 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 296 <div class="directive-section"><h2><a name="DeflateFilterNote" id="DeflateFilterNote">DeflateFilterNote</a> <a name="deflatefilternote" id="deflatefilternote">Directive</a></h2>
 297 <table class="directive">
 298 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Places the compression ratio in a note for logging</td></tr>
 299 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateFilterNote [<var>type</var>] <var>notename</var></code></td></tr>
 300 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 301 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 302 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 303 </table>
 304     <p>The <code class="directive">DeflateFilterNote</code> directive
 305     specifies that a note about compression ratios should be attached
 306     to the request. The name of the note is the value specified for
 307     the directive. You can use that note for statistical purposes by
 308     adding the value to your <a href="../logs.html#accesslog">access log</a>.</p>
 309
 310     <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">      DeflateFilterNote ratio
 311
 312       LogFormat '"%r" %b (%{ratio}n) "%{User-agent}i"' deflate
 313       CustomLog logs/deflate_log deflate</pre>
 314 </div>
 315
 316     <p>If you want to extract more accurate values from your logs, you
 317     can use the <var>type</var> argument to specify the type of data
 318     left as a note for logging. <var>type</var> can be one of:</p>
 319
 320     <dl>
 321       <dt><code>Input</code></dt>
 322       <dd>Store the byte count of the filter's input stream in the note.</dd>
 323
 324       <dt><code>Output</code></dt>
 325       <dd>Store the byte count of the filter's output stream in the note.</dd>
 326
 327       <dt><code>Ratio</code></dt>
 328       <dd>Store the compression ratio (<code>output/input * 100</code>)
 329       in the note. This is the default, if the <var>type</var> argument
 330       is omitted.</dd>
 331     </dl>
 332
 333     <p>Thus you may log it this way:</p>
 334
 335     <div class="example"><h3>Accurate Logging</h3><pre class="prettyprint lang-config">DeflateFilterNote Input instream
 336 DeflateFilterNote Output outstream
 337 DeflateFilterNote Ratio ratio
 338
 339 LogFormat '"%r" %{outstream}n/%{instream}n (%{ratio}n%%)' deflate
 340 CustomLog logs/deflate_log deflate</pre>
 341 </div>
 342
 343 <h3>See also</h3>
 344 <ul>
 345 <li><code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code></li>
 346 </ul>
 347 </div>
 348 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 349 <div class="directive-section"><h2><a name="DeflateInflateLimitRequestBody" id="DeflateInflateLimitRequestBody">DeflateInflateLimitRequestBody</a> <a name="deflateinflatelimitrequestbody" id="deflateinflatelimitrequestbody">Directive</a></h2>
 350 <table class="directive">
 351 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum size of inflated request bodies</td></tr>
 352 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateLimitRequestBody<var>value</var></code></td></tr>
 353 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>None, but LimitRequestBody applies after deflation</code></td></tr>
 354 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 355 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 356 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 357 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
 358 </table>
 359     <p>The <code class="directive">DeflateInflateLimitRequestBody</code> directive
 360         specifies the maximum size of an inflated request body. If it is unset,
 361         <code class="directive"><a href="../mod/core.html#limitrequestbody">LimitRequestBody</a></code> is applied to the
 362         inflated body.</p>
 363
 364 </div>
 365 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 366 <div class="directive-section"><h2><a name="DeflateInflateRatioBurst" id="DeflateInflateRatioBurst">DeflateInflateRatioBurst</a> <a name="deflateinflateratioburst" id="deflateinflateratioburst">Directive</a></h2>
 367 <table class="directive">
 368 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of times the inflation ratio for request bodies
 369              can be crossed</td></tr>
 370 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateRatioBurst <var>value</var></code></td></tr>
 371 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>3</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#Status">Status:</a></th><td>Extension</td></tr>
 374 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 375 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
 376 </table>
 377     <p>The <code class="directive">DeflateInflateRatioBurst</code> directive
 378        specifies the maximum number of times the
 379        <code class="directive">DeflateInflateRatioLimit</code> can be crossed before
 380        terminating the request.</p>
 381
 382 </div>
 383 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 384 <div class="directive-section"><h2><a name="DeflateInflateRatioLimit" id="DeflateInflateRatioLimit">DeflateInflateRatioLimit</a> <a name="deflateinflateratiolimit" id="deflateinflateratiolimit">Directive</a></h2>
 385 <table class="directive">
 386 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum inflation ratio for request bodies</td></tr>
 387 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateRatioLimit <var>value</var></code></td></tr>
 388 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>200</code></td></tr>
 389 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
 390 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 391 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 392 <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
 393 </table>
 394     <p>The <code class="directive">DeflateInflateRatioLimit</code> directive
 395         specifies the maximum ratio of deflated to inflated size of an
 396         inflated request body. This ratio is checked as the body is
 397         streamed in, and if crossed more than
 398         <code class="directive">DeflateInflateRatioBurst</code> times, the request
 399         will be terminated.</p>
 400
 401 </div>
 402 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 403 <div class="directive-section"><h2><a name="DeflateMemLevel" id="DeflateMemLevel">DeflateMemLevel</a> <a name="deflatememlevel" id="deflatememlevel">Directive</a></h2>
 404 <table class="directive">
 405 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How much memory should be used by zlib for compression</td></tr>
 406 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateMemLevel <var>value</var></code></td></tr>
 407 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateMemLevel 9</code></td></tr>
 408 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 409 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 410 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 411 </table>
 412     <p>The <code class="directive">DeflateMemLevel</code> directive specifies
 413     how much memory should be used by zlib for compression
 414     (a value between 1 and 9).</p>
 415
 416 </div>
 417 <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
 418 <div class="directive-section"><h2><a name="DeflateWindowSize" id="DeflateWindowSize">DeflateWindowSize</a> <a name="deflatewindowsize" id="deflatewindowsize">Directive</a></h2>
 419 <table class="directive">
 420 <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Zlib compression window size</td></tr>
 421 <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateWindowSize <var>value</var></code></td></tr>
 422 <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateWindowSize 15</code></td></tr>
 423 <tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
 424 <tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
 425 <tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
 426 </table>
 427     <p>The <code class="directive">DeflateWindowSize</code> directive specifies the
 428     zlib compression window size (a value between 1 and 15). Generally, the
 429     higher the window size, the higher can the compression ratio be expected.</p>
 430
 431 </div>
 432 </div>
 433 <div class="bottomlang">
 434 <p><span>Available Languages: </span><a href="../en/mod/mod_deflate.html" title="English">&nbsp;en&nbsp;</a> |
 435 <a href="../fr/mod/mod_deflate.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a> |
 436 <a href="../ja/mod/mod_deflate.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
 437 <a href="../ko/mod/mod_deflate.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
 438 </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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