When working with Apache's mod_rewrite, developers often need to check for exact cookie values in RewriteCond statements. The HTTP_COOKIE server variable contains all cookies in a single string, making exact value matching surprisingly tricky.

The common approaches like:

RewriteCond %{HTTP_COOKIE} its=me [NC]
RewriteCond %{HTTP_COOKIE} ^its=me$ [NC]

fail because:

• HTTP_COOKIE contains all cookies (e.g., "session=abc123; its=me; tracking=1")
• Simple patterns might match partial values ("me" would match "memo")
• The cookie might appear anywhere in the string

The most reliable method uses regex lookaheads and lookbehinds to isolate the cookie value:

RewriteCond %{HTTP_COOKIE} (^|;\s*)its=me($|;)

This pattern ensures:

1. The cookie appears at start or after semicolon
2. Value is exactly "me" (case-insensitive with [NC])
3. Value ends at semicolon or string end

For redirecting when cookie matches exactly:

RewriteEngine On
RewriteCond %{HTTP_COOKIE} (^|;\s*)its=me($|;) [NC]
RewriteRule ^ /special-page [L,R=302]

For blocking requests with invalid cookies:

RewriteCond %{HTTP_COOKIE} (^|;\s*)auth_token=(correct_value)($|;) [NC]
RewriteCond %1 !^correct_value$
RewriteRule ^ - [F]

Use this diagnostic rule to test patterns without affecting users:

RewriteCond %{QUERY_STRING} ^debug-cookie-test$
RewriteCond %{HTTP_COOKIE} (^|;\s*)its=(.*?)($|;)
RewriteRule ^ - [E=MATCHED_VALUE:%2]
Header set X-Cookie-Test "%{MATCHED_VALUE}e" env=MATCHED_VALUE

Access with ?debug-cookie-test to see extracted values in response headers.

When checking multiple cookies:

• Place most common matches first
• Use [OR] flags judiciously
• Consider directives for complex logic

For high-traffic sites, cookie-based rewrites should generally be avoided in favor of application-layer logic.

When exact matching becomes too complex:

# Using mod_setenvif
SetEnvIf Cookie "its=me([;\s]|$)" HAS_EXACT_COOKIE

# In rewrite rules
RewriteCond %{ENV:HAS_EXACT_COOKIE} =1
RewriteRule ^ /special-page [L]

Remember that mod_rewrite rules are processed before most other modules, so environment variables set by mod_setenvif won't be available in very early rewrite phases.

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When working with Apache's mod_rewrite rules, matching exact cookie values in the HTTP_COOKIE string presents unique parsing challenges. The HTTP_COOKIE variable contains the entire Cookie header string, which means we need precise pattern matching to isolate specific name-value pairs.

Standard regex patterns like ^its=me$ don't work because:

Cookie: its=me; othercookie=value
Cookie: its=me2
Cookie: othercookie=value; its=me

All these scenarios break naive matching attempts.

Here's the correct pattern for exact value matching:

RewriteCond %{HTTP_COOKIE} (^|;\s*)its=me($|\s*;) [NC]

This handles all edge cases:

• Cookie at start of string (^)
• Cookie in middle (;\s* prefix)
• Cookie at end ($)
• Cookie followed by another (\s*; suffix)

Basic exact match:

RewriteEngine On
RewriteCond %{HTTP_COOKIE} (^|;\s*)auth_token=abc123($|\s*;) [NC]
RewriteRule ^ /protected-area [L]

Negative matching (when cookie doesn't exist or has wrong value):

RewriteCond %{HTTP_COOKIE} !(^|;\s*)session_valid=true($|\s*;) [NC]
RewriteRule ^ /login [R=302,L]

For complex scenarios with multiple cookies:

RewriteCond %{HTTP_COOKIE} (^|;\s*)user_type=admin($|\s*;) [NC]
RewriteCond %{HTTP_COOKIE} (^|;\s*)session_active=1($|\s*;) [NC]
RewriteRule ^ /admin-dashboard [L]

When dealing with many cookies:

1. Place the most common failure condition first
2. Use [OR] flags judiciously
3. Consider RewriteMap for complex matching logic

Enable verbose logging with:

RewriteLog "/var/log/apache2/rewrite.log"
RewriteLogLevel 3

Watch for false positives/negatives in your pattern matching.