CentOS7.4/Apache2.4.6下基于HTTP_REFERER的动态重定向配置咨询

Alright, let's get this redirect logic working for your CentOS 7.4 / Apache 2.4.6 setup. We'll use Apache's mod_rewrite module here—it's perfect for handling conditional redirects based on HTTP headers and file system checks.

First, Make Sure mod_rewrite is Enabled #

Before diving into the rules, confirm mod_rewrite is active on your server:

httpd -M | grep rewrite

If you don't see rewrite_module (shared) in the output, enable it by editing your Apache config (usually /etc/httpd/conf/httpd.conf or /etc/httpd/conf.d/rewrite.conf):

LoadModule rewrite_module modules/mod_rewrite.so

Then restart Apache to apply the change:

systemctl restart httpd

The Rewrite Rules #

You can add these rules either directly in your Apache server config (inside a <Directory> block for your website root) or in a .htaccess file in your site's root directory.

Here's the complete rule set:

RewriteEngine On

# Match requests for /bb.html
RewriteCond %{REQUEST_URI} ^/bb\.html$ [NC]
# Extract the test file name (like test01.html) from the HTTP_REFERER
# Adjust the regex here if your Referer URLs follow a different structure
RewriteCond %{HTTP_REFERER} ^https?://example\.jp/.*/([^/]+\.html)$ [NC]
# Store the captured test file name in an environment variable
RewriteRule ^ - [E=TEST_FILE:%1]

# Check if the target test file exists on the server
RewriteCond %{DOCUMENT_ROOT}/bb/bb/homepage/%{ENV:TEST_FILE} -f
# If it exists, redirect to that file (use R=301 for permanent redirects)
RewriteRule ^/bb\.html$ /bb/bb/homepage/%{ENV:TEST_FILE} [R=302,L]

# If the test file doesn't exist, redirect to homepage.html
RewriteRule ^/bb\.html$ /bb/bb/homepage.html [R=302,L]

Let's Break Down Each Part #

• RewriteEngine On: Turns on the mod_rewrite engine—required for all rewrite rules.
• First RewriteCond: Ensures we only apply these rules when the user is accessing /bb.html ([NC] makes the match case-insensitive).
• Second RewriteCond: Extracts the HTML filename (like test01.html) from the HTTP Referer header. The regex assumes your Referer URLs look like http://example.jp/some/path/test01.html—adjust the regex if your Referer structure is different (e.g., if test files are always under a specific path).
• RewriteRule ^ - [E=TEST_FILE:%1]: Saves the captured filename to an environment variable TEST_FILE so we can reuse it later.
• Next RewriteCond: Checks if the file /bb/bb/homepage/{captured-file} exists on the server (-f means "is a regular file").
• First RewriteRule: If the file exists, redirect the user to that path. Use R=301 instead of R=302 if you want this to be a permanent redirect. The [L] flag tells Apache to stop processing further rules once this one is applied.
• Final RewriteRule: If the test file doesn't exist, this rule kicks in and redirects the user to /bb/bb/homepage.html.

Important Notes #

• Document Root: CentOS 7.4's default Apache document root is /var/www/html. If your site uses a different root, make sure %{DOCUMENT_ROOT} points to it, or replace it with the full absolute path to your site's root.
• .htaccess Permissions: If using .htaccess, ensure your Apache <Directory> block for the site root has AllowOverride All set—otherwise, the rules in .htaccess won't be applied.
• Testing: Use tools like curl to test the redirects without a browser:

  # Test with a Referer that points to an existing test file
  curl -v -H "Referer: http://example.jp/foo/test01.html" http://example.jp/bb.html
  # Test with a Referer that points to a non-existent test file
  curl -v -H "Referer: http://example.jp/foo/test99.html" http://example.jp/bb.html
  

内容的提问来源于stack exchange，提问作者Akinobu Katou