mod_deflate.html.en 28.4 KB
Newer Older
powelld's avatar
powelld committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head>
<meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type" />
<!--
        XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
              This file is generated from xml source: DO NOT EDIT
        XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      -->
<title>mod_deflate - Apache HTTP Server Version 2.4</title>
<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" />
<script src="../style/scripts/prettify.min.js" type="text/javascript">
</script>

<link href="../images/favicon.ico" rel="shortcut icon" /></head>
<body>
<div id="page-header">
<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.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>
<p class="apache">Apache HTTP Server Version 2.4</p>
<img alt="" src="../images/feather.png" /></div>
<div class="up"><a href="./"><img title="&lt;-" alt="&lt;-" src="../images/left.gif" /></a></div>
<div id="path">
<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 2.4</a> &gt; <a href="./">Modules</a></div>
<div id="page-content">
<div id="preamble"><h1>Apache Module mod_deflate</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="../en/mod/mod_deflate.html" title="English">&nbsp;en&nbsp;</a> |
<a href="../fr/mod/mod_deflate.html" hreflang="fr" rel="alternate" title="Franais">&nbsp;fr&nbsp;</a> |
<a href="../ja/mod/mod_deflate.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
<a href="../ko/mod/mod_deflate.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
</div>
<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Compress content before it is delivered to the
client</td></tr>
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">ModuleIdentifier:</a></th><td>deflate_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">SourceFile:</a></th><td>mod_deflate.c</td></tr></table>
<h3>Summary</h3>

    <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module provides
    the <code>DEFLATE</code> output filter that allows output from
    your server to be compressed before being sent to the client over
    the network.</p>
</div>
<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3>
<ul id="topics">
<li><img alt="" src="../images/down.gif" /> <a href="#supportedencodings">Supported Encodings</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#recommended">Sample Configurations</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#enable">Enabling Compression</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#proxies">Dealing with proxy servers</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#precompressed">Serving pre-compressed
content</a></li>
</ul><h3 class="directives">Directives</h3>
<ul id="toc">
<li><img alt="" src="../images/down.gif" /> <a href="#deflatebuffersize">DeflateBufferSize</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflatecompressionlevel">DeflateCompressionLevel</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflatefilternote">DeflateFilterNote</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflateinflatelimitrequestbody">DeflateInflateLimitRequestBody</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflateinflateratioburst">DeflateInflateRatioBurst</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflateinflateratiolimit">DeflateInflateRatioLimit</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflatememlevel">DeflateMemLevel</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#deflatewindowsize">DeflateWindowSize</a></li>
</ul>
<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>
<ul class="seealso">
<li><a href="../filter.html">Filters</a></li>
<li><a href="#comments_section">Comments</a></li></ul></div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="supportedencodings" id="supportedencodings">Supported Encodings</a></h2>
  <p>The <code>gzip</code> encoding is the only one supported to ensure complete compatibility
  with old browser implementations. The <code>deflate</code> encoding is not supported, 
  please check the <a href="http://www.gzip.org/zlib/zlib_faq.html#faq38">zlib's documentation</a>
  for a complete explanation.
  </p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="recommended" id="recommended">Sample Configurations</a></h2>
    <div class="warning"><h3>Compression and TLS</h3>
        <p>Some web applications are vulnerable to an information disclosure
        attack when a TLS connection carries deflate compressed data. For more
        information, review the details of the "BREACH" family of attacks.</p>
    </div>
    <p>This is a simple configuration that compresses common text-based content types.</p>

    <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>
</div>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="enable" id="enable">Enabling Compression</a></h2>
    <div class="warning"><h3>Compression and TLS</h3>
        <p>Some web applications are vulnerable to an information disclosure
        attack when a TLS connection carries deflate compressed data. For more
        information, review the details of the "BREACH" family of attacks.</p>
    </div>

    <h3><a name="output" id="output">Output Compression</a></h3>
      <p>Compression is implemented by the <code>DEFLATE</code>
      <a href="../filter.html">filter</a>. The following directive
      will enable compression for documents in the container where it
      is placed:</p>

      <pre class="prettyprint lang-config">SetOutputFilter DEFLATE
SetEnvIfNoCase Request_URI "\.(?:gif|jpe?g|png)$" no-gzip</pre>


      <p>If you want to restrict the compression to particular MIME types
      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
      enabling compression only for the html files of the Apache
      documentation:</p>

      <pre class="prettyprint lang-config">&lt;Directory "/your-server-root/manual"&gt;
    AddOutputFilterByType DEFLATE text/html
&lt;/Directory&gt;</pre>


      <div class="note"><h3>Note</h3>
        The <code>DEFLATE</code> filter is always inserted after RESOURCE
        filters like PHP or SSI. It never touches internal subrequests.
      </div>
      <div class="note"><h3>Note</h3>
        There is an environment variable <code>force-gzip</code>,
        set via <code class="directive"><a href="../mod/mod_env.html#setenv">SetEnv</a></code>, which
        will ignore the accept-encoding setting of your browser and will
        send compressed output.
      </div>

    
    <h3><a name="inflate" id="inflate">Output Decompression</a></h3>
      <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module also provides a filter for
      inflating/uncompressing a gzip compressed response body. In order to activate
      this feature you have to insert the <code>INFLATE</code> filter into
      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>

      <pre class="prettyprint lang-config">&lt;Location "/dav-area"&gt;
    ProxyPass "http://example.com/"
    SetOutputFilter INFLATE
&lt;/Location&gt;</pre>


      <p>This Example will uncompress gzip'ed output from example.com, so other
      filters can do further processing with it.
      </p>

    
    <h3><a name="input" id="input">Input Decompression</a></h3>
      <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module also provides a filter for
      decompressing a gzip compressed request body . In order to activate
      this feature you have to insert the <code>DEFLATE</code> filter into
      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>

      <pre class="prettyprint lang-config">&lt;Location "/dav-area"&gt;
    SetInputFilter DEFLATE
&lt;/Location&gt;</pre>


      <p>Now if a request contains a <code>Content-Encoding:
      gzip</code> header, the body will be automatically decompressed.
      Few browsers have the ability to gzip request bodies. However,
      some special applications actually do support request
      compression, for instance some <a href="http://www.webdav.org">WebDAV</a> clients.</p>

      <div class="warning"><h3>Note on Content-Length</h3>
        <p>If you evaluate the request body yourself, <em>don't trust
        the <code>Content-Length</code> header!</em>
        The Content-Length header reflects the length of the
        incoming data from the client and <em>not</em> the byte count of
        the decompressed data stream.</p>
      </div>
    
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="proxies" id="proxies">Dealing with proxy servers</a></h2>

    <p>The <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> module sends a <code>Vary:
    Accept-Encoding</code> HTTP response header to alert proxies that
    a cached response should be sent only to clients that send the
    appropriate <code>Accept-Encoding</code> request header.  This
    prevents compressed content from being sent to a client that will
    not understand it.</p>

    <p>If you use some special exclusions dependent
    on, for example, the <code>User-Agent</code> header, you must
    manually configure an addition to the <code>Vary</code> header
    to alert proxies of the additional restrictions.  For example,
    in a typical configuration where the addition of the <code>DEFLATE</code>
    filter depends on the <code>User-Agent</code>, you should add:</p>

    <pre class="prettyprint lang-config">Header append Vary User-Agent</pre>


    <p>If your decision about compression depends on other information
    than request headers (<em>e.g.</em> HTTP version), you have to set the
    <code>Vary</code> header to the value <code>*</code>. This prevents
    compliant proxies from caching entirely.</p>

    <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">Header set Vary *</pre>
</div>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="precompressed" id="precompressed">Serving pre-compressed
content</a></h2>

    <p>Since <code class="module"><a href="../mod/mod_deflate.html">mod_deflate</a></code> re-compresses content each 
    time a request is made, some performance benefit can be derived by
    pre-compressing the content and telling mod_deflate to serve them
    without re-compressing them. This may be accomplished using a
    configuration like the following:</p>

    <pre class="prettyprint lang-config">&lt;IfModule mod_headers.c&gt;
    # Serve gzip compressed CSS files if they exist 
    # and the client accepts gzip.
    RewriteCond "%{HTTP:Accept-encoding}" "gzip"
    RewriteCond "%{REQUEST_FILENAME}\.gz" -s
    RewriteRule "^(.*)\.css" "$1\.css\.gz" [QSA]

    # Serve gzip compressed JS files if they exist 
    # and the client accepts gzip.
    RewriteCond "%{HTTP:Accept-encoding}" "gzip"
    RewriteCond "%{REQUEST_FILENAME}\.gz" -s
    RewriteRule "^(.*)\.js" "$1\.js\.gz" [QSA]


    # Serve correct content types, and prevent mod_deflate double gzip.
    RewriteRule "\.css\.gz$" "-" [T=text/css,E=no-gzip:1]
    RewriteRule "\.js\.gz$" "-" [T=text/javascript,E=no-gzip:1]


    &lt;FilesMatch "(\.js\.gz|\.css\.gz)$"&gt;
      # Serve correct encoding type.
      Header append Content-Encoding gzip

      # Force proxies to cache gzipped &amp; 
      # non-gzipped css/js files separately.
      Header append Vary Accept-Encoding
    &lt;/FilesMatch&gt;
&lt;/IfModule&gt;</pre>


</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateBufferSize" id="DeflateBufferSize">DeflateBufferSize</a> <a name="deflatebuffersize" id="deflatebuffersize">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Fragment size to be compressed at one time by zlib</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateBufferSize <var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateBufferSize 8096</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
</table>
    <p>The <code class="directive">DeflateBufferSize</code> directive specifies
    the size in bytes of the fragments that zlib should compress at one
    time. If the compressed response size is bigger than the one specified
    by this directive then httpd will switch to chunked encoding 
    (HTTP header <code>Transfer-Encoding</code> set to <code>Chunked</code>), with the
    side effect of not setting any <code>Content-Length</code> HTTP header. This is particularly 
    important when httpd works behind reverse caching proxies or when httpd is configured with 
    <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
    HTTP responses without any <code>Content-Length</code> header might not be cached.
  </p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateCompressionLevel" id="DeflateCompressionLevel">DeflateCompressionLevel</a> <a name="deflatecompressionlevel" id="deflatecompressionlevel">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How much compression do we apply to the output</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateCompressionLevel <var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Zlib's default</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
</table>
    <p>The <code class="directive">DeflateCompressionLevel</code> directive specifies
        what level of compression should be used, the higher the value,
        the better the compression, but the more CPU time is required to
        achieve this.</p>
    <p>The value must between 1 (less compression) and 9 (more compression).</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateFilterNote" id="DeflateFilterNote">DeflateFilterNote</a> <a name="deflatefilternote" id="deflatefilternote">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Places the compression ratio in a note for logging</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateFilterNote [<var>type</var>] <var>notename</var></code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
</table>
    <p>The <code class="directive">DeflateFilterNote</code> directive
    specifies that a note about compression ratios should be attached
    to the request. The name of the note is the value specified for
    the directive. You can use that note for statistical purposes by
    adding the value to your <a href="../logs.html#accesslog">access log</a>.</p>

    <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">      DeflateFilterNote ratio
    
      LogFormat '"%r" %b (%{ratio}n) "%{User-agent}i"' deflate
      CustomLog "logs/deflate_log" deflate</pre>
</div>

    <p>If you want to extract more accurate values from your logs, you
    can use the <var>type</var> argument to specify the type of data
    left as a note for logging. <var>type</var> can be one of:</p>

    <dl>
      <dt><code>Input</code></dt>
      <dd>Store the byte count of the filter's input stream in the note.</dd>

      <dt><code>Output</code></dt>
      <dd>Store the byte count of the filter's output stream in the note.</dd>

      <dt><code>Ratio</code></dt>
      <dd>Store the compression ratio (<code>output/input * 100</code>)
      in the note. This is the default, if the <var>type</var> argument
      is omitted.</dd>
    </dl>

    <p>Thus you may log it this way:</p>

    <div class="example"><h3>Accurate Logging</h3><pre class="prettyprint lang-config">DeflateFilterNote Input instream
DeflateFilterNote Output outstream
DeflateFilterNote Ratio ratio

LogFormat '"%r" %{outstream}n/%{instream}n (%{ratio}n%%)' deflate
CustomLog "logs/deflate_log" deflate</pre>
</div>

<h3>See also</h3>
<ul>
<li><code class="module"><a href="../mod/mod_log_config.html">mod_log_config</a></code></li>
</ul>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateInflateLimitRequestBody" id="DeflateInflateLimitRequestBody">DeflateInflateLimitRequestBody</a> <a name="deflateinflatelimitrequestbody" id="deflateinflatelimitrequestbody">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum size of inflated request bodies</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateLimitRequestBody<var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>None, but LimitRequestBody applies after deflation</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
</table>
    <p>The <code class="directive">DeflateInflateLimitRequestBody</code> directive 
        specifies the maximum size of an inflated request body. If it is unset,
        <code class="directive"><a href="../mod/core.html#limitrequestbody">LimitRequestBody</a></code> is applied to the
        inflated body.</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateInflateRatioBurst" id="DeflateInflateRatioBurst">DeflateInflateRatioBurst</a> <a name="deflateinflateratioburst" id="deflateinflateratioburst">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of times the inflation ratio for request bodies 
             can be crossed</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateRatioBurst <var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>3</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
</table>
    <p>The <code class="directive">DeflateInflateRatioBurst</code> directive 
       specifies the maximum number of times the 
       <code class="directive">DeflateInflateRatioLimit</code> can be crossed before 
       terminating the request.</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateInflateRatioLimit" id="DeflateInflateRatioLimit">DeflateInflateRatioLimit</a> <a name="deflateinflateratiolimit" id="deflateinflateratiolimit">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum inflation ratio for request bodies</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateInflateRatioLimit <var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>200</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host, directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>2.4.10 and later</td></tr>
</table>
    <p>The <code class="directive">DeflateInflateRatioLimit</code> directive 
        specifies the maximum ratio of deflated to inflated size of an 
        inflated request body. This ratio is checked as the body is
        streamed in, and if crossed more than 
        <code class="directive">DeflateInflateRatioBurst</code> times, the request
        will be terminated.</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateMemLevel" id="DeflateMemLevel">DeflateMemLevel</a> <a name="deflatememlevel" id="deflatememlevel">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>How much memory should be used by zlib for compression</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateMemLevel <var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateMemLevel 9</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
</table>
    <p>The <code class="directive">DeflateMemLevel</code> directive specifies
    how much memory should be used by zlib for compression
    (a value between 1 and 9).</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="DeflateWindowSize" id="DeflateWindowSize">DeflateWindowSize</a> <a name="deflatewindowsize" id="deflatewindowsize">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Zlib compression window size</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>DeflateWindowSize <var>value</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>DeflateWindowSize 15</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_deflate</td></tr>
</table>
    <p>The <code class="directive">DeflateWindowSize</code> directive specifies the
    zlib compression window size (a value between 1 and 15). Generally, the
    higher the window size, the higher can the compression ratio be expected.</p>

</div>
</div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="../en/mod/mod_deflate.html" title="English">&nbsp;en&nbsp;</a> |
<a href="../fr/mod/mod_deflate.html" hreflang="fr" rel="alternate" title="Franais">&nbsp;fr&nbsp;</a> |
<a href="../ja/mod/mod_deflate.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
<a href="../ko/mod/mod_deflate.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a></p>
</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>
<script type="text/javascript"><!--//--><![CDATA[//><!--
var comments_shortname = 'httpd';
var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/mod_deflate.html';
(function(w, d) {
    if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
        d.write('<div id="comments_thread"><\/div>');
        var s = d.createElement('script');
        s.type = 'text/javascript';
        s.async = true;
        s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
        (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
    }
    else { 
        d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
    }
})(window, document);
//--><!]]></script></div><div id="footer">
<p class="apache">Copyright 2017 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.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></div><script type="text/javascript"><!--//--><![CDATA[//><!--
if (typeof(prettyPrint) !== 'undefined') {
    prettyPrint();
}
//--><!]]></script>
</body></html>