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Edge Rules allow you to define logic that runs directly on bunny.net’s edge servers before a request reaches your origin. Rules can modify caching behavior, redirect traffic, route requests to different origins, apply security actions, and more based on request conditions. Edge Rule conditions often evaluate values such as:
  • Cookie Value
  • Country Code (2 letter)
  • Country State Code
  • File Extension
  • Origin Retry Attempt Count
  • Query String
  • Random Chance (%)
  • Remote IP
  • Request Header
  • Request Method
  • Request URL
  • Response Header
  • Response Status Code
In many cases, simple string or wildcard matching is sufficient. However, modern applications frequently generate URLs and request values that follow predictable patterns rather than fixed strings. Examples include:
  • Streaming manifests
  • Versioned build assets
  • Dynamically generated API routes
To make these scenarios easier to handle, Edge Rules support pattern matching using Lua patterns.

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Using Pattern Matching

Pattern matching can be used in any Edge Rule condition that evaluates a request value. To enable pattern matching, prefix the value with:
Example:
The pattern: prefix instructs the Edge Rule engine to evaluate the value using Lua pattern matching instead of a standard string comparison. Lua patterns are similar to regular expressions but intentionally simpler and optimized for performance.

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Anchoring the Pattern

Patterns should normally be wrapped with:
This ensures the entire value is matched, rather than matching a substring. If the pattern: prefix is not used, the condition behaves as a normal string comparison.

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Example

Pattern:
Matches URLs such as:
Internally, Edge Rules evaluate patterns using Lua’s string.find function. This provides efficient pattern matching without requiring a full regular expression engine.

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Example Use Cases

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Matching Streaming Manifests

Streaming platforms often generate manifest files containing region identifiers or session identifiers in the filename. Example URLs:
A pattern condition can match these files and apply actions such as:
  • Custom cache control
  • Edge redirects
  • Request routing

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Targeting Versioned Assets

Many build systems generate versioned assets:
A pattern condition allows matching all versions using a single rule. Common use cases include:
  • Cache rules
  • Rate limiting
  • Header modification

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Security Filtering

Pattern matching can also be used in security rules. Example scenarios:
  • Blocking administrative endpoints
  • Detecting suspicious request patterns
  • Filtering specific URL structures
These rules can be combined with conditions such as cookie presence or header values.

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Lua Pattern Cheat Sheet

Edge Rules use Lua patterns, which are simpler than full regular expressions.

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Format

Edge Rules evaluate patterns using Lua’s string.find.

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Anchors

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Character Classes

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Repeaters

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Escaping Characters

Use % to escape special characters. Examples:

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Limitations

Lua patterns are intentionally simpler than full regular expressions. Unsupported features include:
  • Alternation (|)
  • Lookaheads / lookbehinds
  • Full PCRE syntax
These limitations help ensure pattern evaluation remains fast and predictable across the edge network.