Skip to content

J
joohanhong
Switch branch/tag
Find file
Normal viewHistoryPermalink
advanced.html.en 19.3 KB
Newer Older
JooHan Hong's avatar
SWARM, Docker 소스파일 init
a1dce81a
 
JooHan Hong 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 
<?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><!--
        XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
              This file is generated from xml source: DO NOT EDIT
        XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      -->
<title>Advanced Techniques with mod_rewrite - Apache HTTP Server Version 2.2</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 id="manual-page"><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 2.2</p>
<img alt="" src="../images/feather.gif" /></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 2.2</a> &gt; <a href="./">Rewrite</a></div><div id="page-content"><div id="preamble"><h1>Advanced Techniques with mod_rewrite</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="../en/rewrite/advanced.html" title="English">&nbsp;en&nbsp;</a></p>
</div>


<p>This document supplements the <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>
<a href="../mod/mod_rewrite.html">reference documentation</a>. It provides
a few advanced techniques and tricks using mod_rewrite.</p>

<div class="warning">Note that many of these examples won't work unchanged in your
particular server configuration, so it's important that you understand
them, rather than merely cutting and pasting the examples into your
configuration.</div>

</div>
<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#sharding">URL-based sharding accross multiple backends</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#on-the-fly-content">On-the-fly Content-Regeneration</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#load-balancing">Load Balancing</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#autorefresh">Document With Autorefresh</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#structuredhomedirs">Structured Userdirs</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#redirectanchors">Redirecting Anchors</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#time-dependent">Time-Dependent Rewriting</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#setenvvars">Set Environment Variables Based On URL Parts</a></li>
</ul><h3>See also</h3><ul class="seealso"><li><a href="../mod/mod_rewrite.html">Module documentation</a></li><li><a href="intro.html">mod_rewrite introduction</a></li><li><a href="remapping.html">Redirection and remapping</a></li><li><a href="access.html">Controlling access</a></li><li><a href="vhosts.html">Virtual hosts</a></li><li><a href="proxy.html">Proxying</a></li><li><a href="rewritemap.html">Using RewriteMap</a></li><li><a href="avoid.html">When not to use mod_rewrite</a></li></ul><ul class="seealso"><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="sharding" id="sharding">URL-based sharding accross multiple backends</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>A common technique for distributing the burden of
      server load or storage space is called "sharding".
      When using this method, a front-end server will use the
      url to consistently "shard" users or objects to separate
      backend servers.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>A mapping is maintained, from users to target servers, in
      external map files. They look like:</p>

<div class="example"><p><code>
user1  physical_host_of_user1<br />
user2  physical_host_of_user2<br />
:      :
</code></p></div>

  <p>We put this into a <code>map.users-to-hosts</code> file. The
    aim is to map;</p>

<div class="example"><p><code>
/u/user1/anypath
</code></p></div>

  <p>to</p>

<div class="example"><p><code>
http://physical_host_of_user1/u/user/anypath
</code></p></div>

      <p>thus every URL path need not be valid on every backend physical
      host. The following ruleset does this for us with the help of the map
      files assuming that server0 is a default server which will be used if
      a user has no entry in the map:</p>

<div class="example"><p><code>
RewriteEngine on<br />
<br />
RewriteMap      users-to-hosts   txt:/path/to/map.users-to-hosts<br />
<br />
RewriteRule   ^/u/<strong>([^/]+)</strong>/?(.*)   http://<strong>${users-to-hosts:$1|server0}</strong>/u/$1/$2
</code></p></div>
    </dd>
  </dl>

  <p>See the <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code>
  documentation for more discussion of the syntax of this directive.</p>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="on-the-fly-content" id="on-the-fly-content">On-the-fly Content-Regeneration</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>We wish to dynamically generate content, but store it
      statically once it is generated. This rule will check for the
      existence of the static file, and if it's not there, generate
      it. The static files can be removed periodically, if desired (say,
      via cron) and will be regenerated on demand.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      This is done via the following ruleset:

<pre class="prettyprint lang-config"># This example is valid in per-directory context only
RewriteCond %{REQUEST_URI}   !-U
RewriteRule ^(.+)\.html$          /regenerate_page.cgi   [PT,L]</pre>


    <p>The <code>-U</code> operator determines whether the test string
    (in this case, <code>REQUEST_URI</code>) is a valid URL. It does
    this via a subrequest. In the event that this subrequest fails -
    that is, the requested resource doesn't exist - this rule invokes
    the CGI program <code>/regenerate_page.cgi</code>, which generates
    the requested resource and saves it into the document directory, so
    that the next time it is requested, a static copy can be served.</p>

    <p>In this way, documents that are infrequently updated can be served in
    static form. if documents need to be refreshed, they can be deleted
    from the document directory, and they will then be regenerated the
    next time they are requested.</p>
    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="load-balancing" id="load-balancing">Load Balancing</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>We wish to randomly distribute load across several servers
      using mod_rewrite.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>We'll use <code class="directive"><a href="../mod/mod_rewrite.html#rewritemap">RewriteMap</a></code> and a list of servers
      to accomplish this.</p>

<div class="example"><p><code>
RewriteEngine on<br />
RewriteMap lb rnd:/path/to/serverlist.txt<br />
<br />
RewriteRule ^/(.*) http://${lb:servers}/$1 [P,L]
</code></p></div>

<p><code>serverlist.txt</code> will contain a list of the servers:</p>

<div class="example"><p><code>
## serverlist.txt<br />
<br />
servers one.example.com|two.example.com|three.example.com<br />
</code></p></div>

<p>If you want one particular server to get more of the load than the
others, add it more times to the list.</p>

   </dd>

   <dt>Discussion</dt>
   <dd>
<p>Apache comes with a load-balancing module -
<code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> - which is far more flexible and
featureful than anything you can cobble together using mod_rewrite.</p>
   </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="autorefresh" id="autorefresh">Document With Autorefresh</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>Wouldn't it be nice, while creating a complex web page, if
      the web browser would automatically refresh the page every
      time we save a new version from within our editor?
      Impossible?</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>No! We just combine the MIME multipart feature, the
      web server NPH feature, and the URL manipulation power of
      <code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>. First, we establish a new
      URL feature: Adding just <code>:refresh</code> to any
      URL causes the 'page' to be refreshed every time it is
      updated on the filesystem.</p>

<div class="example"><p><code>
RewriteRule   ^(/[uge]/[^/]+/?.*):refresh  /internal/cgi/apache/nph-refresh?f=$1
</code></p></div>

      <p>Now when we reference the URL</p>

<div class="example"><p><code>
/u/foo/bar/page.html:refresh
</code></p></div>

      <p>this leads to the internal invocation of the URL</p>

<div class="example"><p><code>
/internal/cgi/apache/nph-refresh?f=/u/foo/bar/page.html
</code></p></div>

      <p>The only missing part is the NPH-CGI script. Although
      one would usually say "left as an exercise to the reader"
      ;-) I will provide this, too.</p>

<div class="example"><pre>#!/sw/bin/perl
##
##  nph-refresh -- NPH/CGI script for auto refreshing pages
##  Copyright (c) 1997 Ralf S. Engelschall, All Rights Reserved.
##
$| = 1;

#   split the QUERY_STRING variable
@pairs = split( /&amp;/, $ENV{'QUERY_STRING'} );
foreach $pair (@pairs) {
    ( $name, $value ) = split( /=/, $pair );
    $name =~ tr/A-Z/a-z/;
    $name = 'QS_' . $name;
    $value =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C", hex($1))/eg;
    eval "\$$name = \"$value\"";
}
$QS_s = 1    if ( $QS_s eq '' );
$QS_n = 3600 if ( $QS_n eq '' );
if ( $QS_f eq '' ) {
    print "HTTP/1.0 200 OK\n";
    print "Content-type: text/html\n\n";
print "&amp;lt;b&amp;gt;ERROR&amp;lt;/b&amp;gt;: No file given\n";
    exit(0);
}
if ( !-f $QS_f ) {
    print "HTTP/1.0 200 OK\n";
    print "Content-type: text/html\n\n";
print "&amp;lt;b&amp;gt;ERROR&amp;lt;/b&amp;gt;: File $QS_f not found\n";
    exit(0);
}

sub print_http_headers_multipart_begin {
    print "HTTP/1.0 200 OK\n";
    $bound = "ThisRandomString12345";
    print "Content-type: multipart/x-mixed-replace;boundary=$bound\n";
    &amp;print_http_headers_multipart_next;
}

sub print_http_headers_multipart_next {
    print "\n--$bound\n";
}

sub print_http_headers_multipart_end {
    print "\n--$bound--\n";
}

sub displayhtml {
    local ($buffer) = @_;
    $len = length($buffer);
    print "Content-type: text/html\n";
    print "Content-length: $len\n\n";
    print $buffer;
}

sub readfile {
    local ($file) = @_;
    local ( *FP, $size, $buffer, $bytes );
    ( $x, $x, $x, $x, $x, $x, $x, $size ) = stat($file);
    $size = sprintf( "%d", $size );
open(FP, "&amp;lt;$file");
    $bytes = sysread( FP, $buffer, $size );
    close(FP);
    return $buffer;
}

$buffer = &amp;readfile($QS_f);
&amp;print_http_headers_multipart_begin;
&amp;displayhtml($buffer);

sub mystat {
    local ($file) = $_[0];
    local ($time);

    ( $x, $x, $x, $x, $x, $x, $x, $x, $x, $mtime ) = stat($file);
    return $mtime;
}

$mtimeL = &amp;mystat($QS_f);
$mtime  = $mtime;
for ( $n = 0 ; $n &amp; lt ; $QS_n ; $n++ ) {
    while (1) {
        $mtime = &amp;mystat($QS_f);
        if ( $mtime ne $mtimeL ) {
            $mtimeL = $mtime;
            sleep(2);
            $buffer = &amp;readfile($QS_f);
            &amp;print_http_headers_multipart_next;
            &amp;displayhtml($buffer);
            sleep(5);
            $mtimeL = &amp;mystat($QS_f);
            last;
        }
        sleep($QS_s);
    }
}

&amp;print_http_headers_multipart_end;

exit(0);

##EOF##</pre></div>
    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="structuredhomedirs" id="structuredhomedirs">Structured Userdirs</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>Some sites with thousands of users use a
      structured homedir layout, <em>i.e.</em> each homedir is in a
      subdirectory which begins (for instance) with the first
      character of the username. So, <code>/~larry/anypath</code>
      is <code>/home/<strong>l</strong>/larry/public_html/anypath</code>
      while <code>/~waldo/anypath</code> is
      <code>/home/<strong>w</strong>/waldo/public_html/anypath</code>.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>We use the following ruleset to expand the tilde URLs
      into the above layout.</p>

<div class="example"><p><code>
RewriteEngine on<br />
RewriteRule   ^/~(<strong>([a-z])</strong>[a-z0-9]+)(.*)  /home/<strong>$2</strong>/$1/public_html$3
</code></p></div>
    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="redirectanchors" id="redirectanchors">Redirecting Anchors</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
    <p>By default, redirecting to an HTML anchor doesn't work,
    because mod_rewrite escapes the <code>#</code> character,
    turning it into <code>%23</code>. This, in turn, breaks the
    redirection.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>Use the <code>[NE]</code> flag on the
      <code>RewriteRule</code>. NE stands for No Escape.
      </p>
    </dd>

    <dt>Discussion:</dt>
    <dd>This technique will of course also work with other
    special characters that mod_rewrite, by default, URL-encodes.</dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="time-dependent" id="time-dependent">Time-Dependent Rewriting</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>We wish to use mod_rewrite to serve different content based on
      the time of day.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>There are a lot of variables named <code>TIME_xxx</code>
      for rewrite conditions. In conjunction with the special
      lexicographic comparison patterns <code>&lt;STRING</code>,
      <code>&gt;STRING</code> and <code>=STRING</code> we can
      do time-dependent redirects:</p>

<div class="example"><p><code>
RewriteEngine on<br />
RewriteCond   %{TIME_HOUR}%{TIME_MIN} &gt;0700<br />
RewriteCond   %{TIME_HOUR}%{TIME_MIN} &lt;1900<br />
RewriteRule   ^foo\.html$             foo.day.html [L]<br />
RewriteRule   ^foo\.html$             foo.night.html
</code></p></div>

      <p>This provides the content of <code>foo.day.html</code>
      under the URL <code>foo.html</code> from
      <code>07:01-18:59</code> and at the remaining time the
      contents of <code>foo.night.html</code>.</p>

      <div class="warning"><code class="module"><a href="../mod/mod_cache.html">mod_cache</a></code>, intermediate proxies
      and browsers may each cache responses and cause the either page to be
      shown outside of the time-window configured.
      <code class="module"><a href="../mod/mod_expires.html">mod_expires</a></code> may be used to control this
      effect. You are, of course, much better off simply serving the
      content dynamically, and customizing it based on the time of day.</div>

    </dd>
  </dl>

</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="setenvvars" id="setenvvars">Set Environment Variables Based On URL Parts</a></h2>

  

  <dl>
    <dt>Description:</dt>

    <dd>
      <p>At time, we want to maintain some kind of status when we
      perform a rewrite. For example, you want to make a note that
      you've done that rewrite, so that you can check later to see if a
      request can via that rewrite. One way to do this is by setting an
      environment variable.</p>
    </dd>

    <dt>Solution:</dt>

    <dd>
      <p>Use the [E] flag to set an environment variable.</p>

<div class="example"><p><code>
RewriteEngine on<br />
RewriteRule   ^/horse/(.*)   /pony/$1 [E=<strong>rewritten:1</strong>]
</code></p></div>

    <p>Later in your ruleset you might check for this environment
    variable using a RewriteCond:</p>

<div class="example"><p><code>
RewriteCond %{ENV:rewritten} =1
</code></p></div>

    </dd>
  </dl>

</div></div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="../en/rewrite/advanced.html" title="English">&nbsp;en&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/2.2/rewrite/advanced.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 2014 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>