Cache-Key Rewrite

This capability requires Rules Engine - Advanced Rules which must be purchased separately. Contact your CDN account manager to activate it.

Category: Caching

Purpose: Rewrites the cache-keyA relative path that uniquely identifies an asset for the purpose of caching. Our edge servers use this relative path when checking for cached content and when caching content. By default, a cache-key will not contain query string parameters. associated with a request.

A cache-key is the relative path that identifies an asset for the purposes of caching. In other words, our servers will check for a cached version of an asset according to the path defined in its cache-key.

Configure this feature by defining both of the following options:

Option	Description
Source	Identify requests whose cache-key will be rewritten via a relative path. This relative path, which starts directly after the hostname in the CDN URL, is shown in blue font below. http://can.0001.transactcdn.com/800001/myorigin/path/file.ext Verify that the specified pattern does not conflict with the parent match conditions defined for this feature. Valid syntax varies according to the number of customer origins that you would like to match. Specific Origin: Match against a specific origin by specifying it via a content access pointThis URL segment of a CDN URL identifies where the request should be directed. This relative path starts directly after the CDN hostname. The proper syntax for a content access point is "/yyAN," where "yy" stands for the origin identifier and "AN" stands for a customer account number. A content access point for a customer origin also includes a directory that identifies it. followed by a regular expression for the desired path. Syntax: Content Access Point/Regular Expression Example: Match all requests to a customer origin called myorigin via the following syntax: /800001/myorigin/(.) Multiple Customer Origins: Match against multiple origins by delimiting each desired customer origin using a \|. Syntax: /80Account Number/(Origin 1\|Origin 2\|Origin N)/Regular Expression Example: Use this pattern to define a capture group that matches a customer origin group called marketing or sales: /800001/(marketing\|sales)/Regular Expression All Customer Origins: Match against all of your customer origins by specifying . or (.). Syntax: /80Account Number/(.)/Regular Expression Example: Use this pattern to define a capture group that matches all of your customer origins: /800001/(.*)/Regular Expression You may only define a customer origin using a literal value (e.g., marketing) or one of the regular expressions patterns defined above. All other regular expression syntax is disallowed when defining a customer origin. This limitation does not apply to the relative path defined after the content access point.
Destination	Identify the new cache-key via a relative path. This relative path, which starts directly after the hostname in the CDN URL, is shown in blue font in the following sample CDN URL. http://can.0001.transactcdn.com/800001/CustomerOrigin/Path/file.ext Use HTTP variables to dynamically construct this relative path. However, you may not use response metadata (e.g., %{resp_ResponseHeader}) when defining a cache-key. Valid syntax varies according to number of origins being matched in the Source option. Specific Origin: Specify the content access pointThis URL segment of a CDN URL identifies where the request should be directed. This relative path starts directly after the CDN hostname. The proper syntax for a content access point is "/yyAN," where "yy" stands for the origin identifier and "AN" stands for a customer account number. A content access point for a customer origin also includes a directory that identifies it. that identifies the desired origin followed by a regular expression for the desired path. Syntax: Content Access Point/Regular Expression Example: Use a backreference (i.e., $1) to include text captured from the source. /800001/mycustomerorigin/new-path/$1 All or Multiple Customer Origins: If the Source option matches all or multiple customer origins using a capture group, then you may use a backreference (i.e., $1) to reinsert the name of the customer origin into the cache-key. Syntax: /80Account Number/$1/Regular Expression Example: Use this pattern to ensure that requests point to the same customer origin: /800001/$1/Regular Expression You may define a customer origin using either a literal value (e.g., marketing) or a backreference. All other regular expression syntax is disallowed when defining a customer origin. This limitation does not apply to the relative path defined after the content access point.

Option

Description

Source

Identify requests whose cache-key will be rewritten via a relative path. This relative path, which starts directly after the hostname in the CDN URL, is shown in blue font below.

http://can.0001.transactcdn.com/800001/myorigin/path/file.ext

Verify that the specified pattern does not conflict with the parent match conditions defined for this feature.

Valid syntax varies according to the number of customer origins that you would like to match.

Specific Origin: Match against a specific origin by specifying it via a content access pointThis URL segment of a CDN URL identifies where the request should be directed. This relative path starts directly after the CDN hostname. The proper syntax for a content access point is "/yyAN," where "yy" stands for the origin identifier and "AN" stands for a customer account number. A content access point for a customer origin also includes a directory that identifies it. followed by a regular expression for the desired path.

Syntax:

Content Access Point/Regular Expression

Example:

Match all requests to a customer origin called myorigin via the following syntax:

/800001/myorigin/(.*)
Multiple Customer Origins: Match against multiple origins by delimiting each desired customer origin using a |.

Syntax:

/80Account Number/(Origin 1|Origin 2|Origin N)/Regular Expression

Example:

Use this pattern to define a capture group that matches a customer origin group called marketing or sales:

/800001/(marketing|sales)/Regular Expression
All Customer Origins: Match against all of your customer origins by specifying .* or (.*).

Syntax:

/80Account Number/(.*)/Regular Expression

Example:

Use this pattern to define a capture group that matches all of your customer origins:

/800001/(.*)/Regular Expression

You may only define a customer origin using a literal value (e.g., marketing) or one of the regular expressions patterns defined above. All other regular expression syntax is disallowed when defining a customer origin. This limitation does not apply to the relative path defined after the content access point.

Destination

Identify the new cache-key via a relative path. This relative path, which starts directly after the hostname in the CDN URL, is shown in blue font in the following sample CDN URL.

http://can.0001.transactcdn.com/800001/CustomerOrigin/Path/file.ext

Use HTTP variables to dynamically construct this relative path. However, you may not use response metadata (e.g., %{resp_ResponseHeader}) when defining a cache-key.

Valid syntax varies according to number of origins being matched in the Source option.

Specific Origin: Specify the content access pointThis URL segment of a CDN URL identifies where the request should be directed. This relative path starts directly after the CDN hostname. The proper syntax for a content access point is "/yyAN," where "yy" stands for the origin identifier and "AN" stands for a customer account number. A content access point for a customer origin also includes a directory that identifies it. that identifies the desired origin followed by a regular expression for the desired path.

Syntax:

Content Access Point/Regular Expression

Example:

Use a backreference (i.e., $1) to include text captured from the source.

/800001/mycustomerorigin/new-path/$1
All or Multiple Customer Origins: If the Source option matches all or multiple customer origins using a capture group, then you may use a backreference (i.e., $1) to reinsert the name of the customer origin into the cache-key.

Syntax:

/80Account Number/$1/Regular Expression

Example:

Use this pattern to ensure that requests point to the same customer origin:

/800001/$1/Regular Expression

You may define a customer origin using either a literal value (e.g., marketing) or a backreference. All other regular expression syntax is disallowed when defining a customer origin. This limitation does not apply to the relative path defined after the content access point.

Default Behavior: A request's cache-key is determined by the request URI.