Many posters have problems debugging their RewriteRule and RewriteCond statements within their .htaccess files. Most of these are using a shared hosting service and therefore don't have access to the root server configuration. They cannot avoid using .htaccess files for rewriting and cannot enable a RewriteLogLevel" as many respondents suggest. Also there are many .htaccess-specific pitfalls and constraints are aren't covered well. Setting up a local test LAMP stack involves too much of a learning curve for most.
所以我的问题是我们建议他们如何自己调试他们的规则。以下是我的一些建议。其他建议将不胜感激。
Understand that the mod_rewrite engine cycles through .htaccess files. The engine runs this loop:
do
execute server and vhost rewrites (in the Apache Virtual Host Config)
find the lowest "Per Dir" .htaccess file on the file path with rewrites enabled
if found(.htaccess)
execute .htaccess rewrites (in the user's directory)
while rewrite occurred
So your rules will get executed repeatedly and if you change the URI path then it may end up executing other .htaccessfiles if they exist. So make sure that you terminate this loop, if necessary by adding extra RewriteCond to stop rules firing. Also delete any lower level .htaccess rewrite rulesets unless explicitly intent to use multi-level rulesets.
Make sure that the syntax of each Regexp is correct by testing against a set of test patterns to make sure that is a valid syntax and does what you intend with a fully range of test URIs. See answer below for more details.
Build up your rules incrementally in a test directory. You can make use of the "execute the deepest .htaccess file on the path feature" to set up a separate test directory (tree) and debug rulesets here without screwing up your main rules and stopping your site working. You have to add them one at a time because this is the only way to localise failures to individual rules.
Use a dummy script stub to dump out server and environment variables. (See Listing 2)If your app uses, say, blog/index.php then you can copy this into test/blog/index.php and use it to test out your blog rules in the test subdirectory. You can also use environment variables to make sure that the rewrite engine in interpreting substitution strings correctly, e.g.
RewriteRule ^(.*) - [E=TEST0:%{DOCUMENT_ROOT}/blog/html_cache/$1.html]
and look for these REDIRECT_* variables in the phpinfo dump. BTW, I used this one and discovered on my site that I had to use %{ENV:DOCUMENT_ROOT_REAL} instead. In the case of redirector looping REDIRECT_REDIRECT_* variables list the previous pass. Etc..
Make sure that you don't get bitten by your browser caching incorrect 301 redirects. See answer below. My thanks to Ulrich Palha for this.
The rewrite engine seems sensitive to cascaded rules within an .htaccess context, (that is where a RewriteRule results in a substitution and this falls though to further rules), as I found bugs with internal sub-requests (1), and incorrect PATH_INFO processing which can often be prevents by use of the [NS], [L] and [PT] flags.
还有什么评论或建议吗?
清单1——phpinfo
<?php phpinfo(INFO_ENVIRONMENT|INFO_VARIABLES);
确保每个Regexp的语法是正确的
通过对一组测试模式进行测试，以确保语法有效，并对所有测试uri执行您想要的操作。
See regexpCheck.php below for a simple script that you can add to a private/test directory in your site to help you do this. I've kept this brief rather than pretty. Just past this into a file regexpCheck.php in a test directory to use it on your website. This will help you build up any regexp and test it against a list of test cases as you do so. I am using the PHP PCRE engine here, but having had a look at the Apache source, this is basically identical to the one used in Apache. There are many HowTos and tutorials which provide templates and can help you build your regexp skills.
清单1——regexpCheck.php
<html><head><title>Regexp checker</title></head><body>
<?php
$a_pattern= isset($_POST['pattern']) ? $_POST['pattern'] : "";
$a_ntests = isset($_POST['ntests']) ? $_POST['ntests'] : 1;
$a_test = isset($_POST['test']) ? $_POST['test'] : array();
$res = array(); $maxM=-1;
foreach($a_test as $t ){
$rtn = @preg_match('#'.$a_pattern.'#',$t,$m);
if($rtn == 1){
$maxM=max($maxM,count($m));
$res[]=array_merge( array('matched'), $m );
} else {
$res[]=array(($rtn === FALSE ? 'invalid' : 'non-matched'));
}
}
?> <p> </p>
<form method="post" action="<?php echo $_SERVER['SCRIPT_NAME'];?>">
<label for="pl">Regexp Pattern: </label>
<input id="p" name="pattern" size="50" value="<?php echo htmlentities($a_pattern,ENT_QUOTES,"UTF-8");;?>" />
<label for="n"> Number of test vectors: </label>
<input id="n" name="ntests" size="3" value="<?php echo $a_ntests;?>"/>
<input type="submit" name="go" value="OK"/><hr/><p> </p>
<table><thead><tr><td><b>Test Vector</b></td><td> <b>Result</b></td>
<?php
for ( $i=0; $i<$maxM; $i++ ) echo "<td> <b>\$$i</b></td>";
echo "</tr><tbody>\n";
for( $i=0; $i<$a_ntests; $i++ ){
echo '<tr><td> <input name="test[]" value="',
htmlentities($a_test[$i], ENT_QUOTES,"UTF-8"),'" /></td>';
foreach ($res[$i] as $v) { echo '<td> ',htmlentities($v, ENT_QUOTES,"UTF-8"),' </td>';}
echo "</tr>\n";
}
?> </table></form></body></html>
我观察到一些错误发生在编写.htaccess时
在多个规则中重复使用^(.*)$，使用^(.*)$会导致其他规则在大多数情况下无效，因为它在一次命中中匹配所有url。
因此，如果我们为这个url sapmle/url使用rule，它也会使用这个url sapmle/url/string。
应该使用[L]标志来确保我们的规则已经完成了处理。
应该知道:
%n和$n的差值
%n在%{RewriteCond}部分匹配，$n在%{RewriteRule}部分匹配。
RewriteBase的工作
The RewriteBase directive specifies the URL prefix to be used for
per-directory (htaccess) RewriteRule directives that substitute a
relative path.
This directive is required when you use a relative path in a
substitution in per-directory (htaccess) context unless any of the
following conditions are true:
The original request, and the substitution, are underneath the
DocumentRoot (as opposed to reachable by other means, such as Alias).
The filesystem path to the directory containing the RewriteRule,
suffixed by the relative substitution is also valid as a URL path on
the server (this is rare). In Apache HTTP Server 2.4.16 and later,
this directive may be omitted when the request is mapped via Alias or
mod_userdir.
如果你不是在一个标准的共享主机环境中工作，而是在一个你有管理权限的环境中工作(可能是你的本地测试环境)，确保启用了.htaccess和mod_rewrite。它们在默认Apache安装中被禁用。在这种情况下，在.htaccess文件中配置的任何操作都不起作用，即使正则表达式完全有效。
启用。htaccess:
找到apache2.conf文件，在Debian/Ubuntu的/etc/apache2中，在文件中的section
<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride None
Require all granted
</Directory>
并更改行AllowOverride None为AllowOverride All。
启用mod_rewrite模块:
在Debian/Ubuntu上执行
sudo a2enmod rewrite
顺便说一下，要禁用一个模块，你可以使用a2dismode而不是a2enmode。
完成上述配置更改后，重新启动Apache使其生效:
sudo systemctl restart apache2
确保每个Regexp的语法是正确的
通过对一组测试模式进行测试，以确保语法有效，并对所有测试uri执行您想要的操作。
See regexpCheck.php below for a simple script that you can add to a private/test directory in your site to help you do this. I've kept this brief rather than pretty. Just past this into a file regexpCheck.php in a test directory to use it on your website. This will help you build up any regexp and test it against a list of test cases as you do so. I am using the PHP PCRE engine here, but having had a look at the Apache source, this is basically identical to the one used in Apache. There are many HowTos and tutorials which provide templates and can help you build your regexp skills.
清单1——regexpCheck.php
<html><head><title>Regexp checker</title></head><body>
<?php
$a_pattern= isset($_POST['pattern']) ? $_POST['pattern'] : "";
$a_ntests = isset($_POST['ntests']) ? $_POST['ntests'] : 1;
$a_test = isset($_POST['test']) ? $_POST['test'] : array();
$res = array(); $maxM=-1;
foreach($a_test as $t ){
$rtn = @preg_match('#'.$a_pattern.'#',$t,$m);
if($rtn == 1){
$maxM=max($maxM,count($m));
$res[]=array_merge( array('matched'), $m );
} else {
$res[]=array(($rtn === FALSE ? 'invalid' : 'non-matched'));
}
}
?> <p> </p>
<form method="post" action="<?php echo $_SERVER['SCRIPT_NAME'];?>">
<label for="pl">Regexp Pattern: </label>
<input id="p" name="pattern" size="50" value="<?php echo htmlentities($a_pattern,ENT_QUOTES,"UTF-8");;?>" />
<label for="n"> Number of test vectors: </label>
<input id="n" name="ntests" size="3" value="<?php echo $a_ntests;?>"/>
<input type="submit" name="go" value="OK"/><hr/><p> </p>
<table><thead><tr><td><b>Test Vector</b></td><td> <b>Result</b></td>
<?php
for ( $i=0; $i<$maxM; $i++ ) echo "<td> <b>\$$i</b></td>";
echo "</tr><tbody>\n";
for( $i=0; $i<$a_ntests; $i++ ){
echo '<tr><td> <input name="test[]" value="',
htmlentities($a_test[$i], ENT_QUOTES,"UTF-8"),'" /></td>';
foreach ($res[$i] as $v) { echo '<td> ',htmlentities($v, ENT_QUOTES,"UTF-8"),' </td>';}
echo "</tr>\n";
}
?> </table></form></body></html>
