rewriteguide.html

这个是我在web培训时老师提供的手册

        <dt>方案:</dt>

        <dd>
<div class="example"><pre>
##
##  apache-rproxy.conf -- Apache configuration for Reverse Proxy Usage
##

#   server type
ServerType           standalone
Listen               8000
MinSpareServers      16
StartServers         16
MaxSpareServers      16
MaxClients           16
MaxRequestsPerChild  100

#   server operation parameters
KeepAlive            on
MaxKeepAliveRequests 100
KeepAliveTimeout     15
Timeout              400
IdentityCheck        off
HostnameLookups      off

#   paths to runtime files
PidFile              /path/to/apache-rproxy.pid
LockFile             /path/to/apache-rproxy.lock
ErrorLog             /path/to/apache-rproxy.elog
CustomLog            /path/to/apache-rproxy.dlog "%{%v/%T}t %h -&gt; %{SERVER}e URL: %U"

#   unused paths
ServerRoot           /tmp
DocumentRoot         /tmp
CacheRoot            /tmp
RewriteLog           /dev/null
TransferLog          /dev/null
TypesConfig          /dev/null
AccessConfig         /dev/null
ResourceConfig       /dev/null

#   speed up and secure processing
&lt;Directory /&gt;
Options -FollowSymLinks -SymLinksIfOwnerMatch
AllowOverride None

&lt;/Directory&gt;

#   the status page for monitoring the reverse proxy
&lt;Location /apache-rproxy-status&gt;
SetHandler server-status
&lt;/Location&gt;

#   enable the URL rewriting engine
RewriteEngine        on
RewriteLogLevel      0

#   define a rewriting map with value-lists where
#   mod_rewrite randomly chooses a particular value
RewriteMap     server  rnd:/path/to/apache-rproxy.conf-servers

#   make sure the status page is handled locally
#   and make sure no one uses our proxy except ourself
RewriteRule    ^/apache-rproxy-status.*  -  [L]
RewriteRule    ^(http|ftp)://.*          -  [F]

#   now choose the possible servers for particular URL types
RewriteRule    ^/(.*\.(cgi|shtml))$  to://${server:dynamic}/$1  [S=1]
RewriteRule    ^/(.*)$               to://${server:static}/$1

#   and delegate the generated URL by passing it
#   through the proxy module
RewriteRule    ^to://([^/]+)/(.*)    http://$1/$2   [E=SERVER:$1,P,L]

#   and make really sure all other stuff is forbidden
#   when it should survive the above rules...
RewriteRule    .*                    -              [F]

#   enable the Proxy module without caching
ProxyRequests        on
NoCache              *

#   setup URL reverse mapping for redirect reponses
ProxyPassReverse  /  http://www1.foo.dom/
ProxyPassReverse  /  http://www2.foo.dom/
ProxyPassReverse  /  http://www3.foo.dom/
ProxyPassReverse  /  http://www4.foo.dom/
ProxyPassReverse  /  http://www5.foo.dom/
ProxyPassReverse  /  http://www6.foo.dom/
</pre></div>

<div class="example"><pre>
##
##  apache-rproxy.conf-servers -- Apache/mod_rewrite selection table
##

#   list of backend servers which serve static
#   pages (HTML files and Images, etc.)
static    www1.foo.dom|www2.foo.dom|www3.foo.dom|www4.foo.dom

#   list of backend servers which serve dynamically
#   generated page (CGI programs or mod_perl scripts)
dynamic   www5.foo.dom|www6.foo.dom
</pre></div>
        </dd>
      </dl>

    

    <h3>新的MIME类型，新的服务</h3>

      

      <dl>
        <dt>说明:</dt>

        <dd>
          <p>网上有许多很巧妙的CGI程序，但是用法晦涩，许多网管弃之不用。即使是Apache的MEME类型的动作处理器，也仅仅在CGI程序不需要在其输入中包含特殊URL(<code>PATH_INFO</code>和<code>QUERY_STRINGS</code>)时才很好用。首先，配置一种新的后缀为<code>.scgi</code>(安全CGI)文件类型，其处理器是很常见的<code>cgiwrap</code>程序。问题是：如果使用同类URL规划(见上述)，而用户宿主目录中的一个文件的URL是<code>/u/user/foo/bar.scgi</code> ，可是<code>cgiwrap</code>要求的URL的格式是<code>/~user/foo/bar.scgi/</code> ，以下规则解决了这个问题：</p>

          <div class="example"><pre>
RewriteRule ^/[uge]/<strong>([^/]+)</strong>/\.www/(.+)\.scgi(.*) ...
... /internal/cgi/user/cgiwrap/~<strong>$1</strong>/$2.scgi$3  [NS,<strong>T=application/x-http-cgi</strong>]
</pre></div>

          <p>另外，假设需要使用其他程序：<code>wwwlog</code>(显示<code>access.log</code>中的一个URL子树)和<code>wwwidx</code>(对一个URL子树运行Glimpse)，则必须对这些程序提供URL区域作为其操作对象。比如，对<code>/u/user/foo/</code>执行<code>swwidx</code>程序的超链是这样的：</p>

<div class="example"><pre>
/internal/cgi/user/swwidx?i=/u/user/foo/
</pre></div>

          <p>其缺点是，必须<strong>同时</strong>硬编码超链中的区域和CGI的路径，如果重组了这个区域，就需要花费大量时间来修改各个超链。</p>
        </dd>

        <dt>方案:</dt>

        <dd>
          <p>方案是用一个特殊的新的URL格式，自动拼装CGI参数：</p>

<div class="example"><pre>
RewriteRule   ^/([uge])/([^/]+)(/?.*)/\*  /internal/cgi/user/wwwidx?i=/$1/$2$3/
RewriteRule   ^/([uge])/([^/]+)(/?.*):log /internal/cgi/user/wwwlog?f=/$1/$2$3
</pre></div>

          <p>现在，这个搜索到<code>/u/user/foo/</code>的超链简化成了：</p>

<div class="example"><pre>
HREF="*"
</pre></div>

          <p>它会被内部地自动转换为</p>

<div class="example"><pre>
/internal/cgi/user/wwwidx?i=/u/user/foo/
</pre></div>

          <p>如此，可以为使用&quot;<code>:log</code>&quot;的超链，拼装出调用CGI程序的参数。</p>
        </dd>
      </dl>

    

    <h3>从静态到动态</h3>

      

      <dl>
        <dt>说明:</dt>

        <dd>
          <p>如何无缝转换静态页面<code>foo.html</code>为动态的<code>foo.cgi</code> ，而不为浏览器/用户所察觉。</p>
        </dd>

        <dt>方案:</dt>

        <dd>
          <p>只须重写此URL为CGI-script ，以强制为可以作为CGI-script运行的正确的MIME类型。如此，对<code>/~quux/foo.html</code>的请求其实会执行<code>/~quux/foo.cgi</code> 。</p>

			<div class="example"><pre>
RewriteEngine  on
RewriteBase    /~quux/
RewriteRule    ^foo\.<strong>html</strong>$  foo.<strong>cgi</strong>  [T=<strong>application/x-httpd-cgi</strong>]
</pre></div>
        </dd>
      </dl>

    

    <h3>传输过程中的内容协商</h3>

      

      <dl>
        <dt>说明:</dt>

        <dd>
          <p>这是一个很难解的功能：动态生成的静态页面，即它应该作为静态页面发送(从文件系统中读出，然后直接发出去)，但是如果它丢失了，则由服务器动态生成。这样，可以静态地提供CGI生成的页面，除非有人(或者是一个cronjob)删除了这些静态页面，而且其内容可以得到更新。</p>
        </dd>

        <dt>方案:</dt>

        <dd>以下规则集实现了这个功能：

			<div class="example"><pre>
RewriteCond %{REQUEST_FILENAME}   <strong>!-s</strong>
RewriteRule ^page\.<strong>html</strong>$          page.<strong>cgi</strong>   [T=application/x-httpd-cgi,L]
</pre></div>

          <p>这样，如果<code>page.html</code>不存在或者文件大小为null ，则对<code>page.html</code>的请求会导致<code>page.cgi</code>的运行。其中奥妙在于<code>page.cgi</code>是一个将输出写入<code>page.html</code>的(同时也写入<code>STDOUT</code>)的常规的CGI脚本，执行完毕，服务器则将<code>page.html</code>的内容发出。如果网管需要强制更新其内容，只须删除<code>page.html</code>即可(通常由一个cronjob完成)。</p>
        </dd>
      </dl>

    

    <h3>自动更新的文档</h3>

      

      <dl>
        <dt>说明:</dt>

        <dd>
          <p>建立一个复杂的页面，能够在用编辑器写了一个更新的版本时自动在浏览器上得到刷新，这不是很好吗？这可能吗？</p>
        </dd>

        <dt>方案:</dt>

        <dd>
          <p>这是可行的! 这需要综合利用MIME多成分、web服务器的NPH和<code class="module"><a href="../mod/mod_rewrite.html">mod_rewrite</a></code>的URL操控特性。首先，建立一个新的URL特性：对在文件系统中更新时需要刷新的所有URL加上&quot;<code>:refresh</code>&quot; 。</p>

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

          <p>然后，修改URL</p>

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

          <p>以内部地操控此URL</p>

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

          <p>接着就是NPH-CGI脚本部分了。虽然，人们常说"将此作为一个练习留给读者"，但我还是给出答案了。</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);
    }