CDN:Rewrite origin path

How it works

Notes

• You can configure up to 50 Origin Path Rewrite rules for each domain name.

• The system runs the rewrite rules that are listed on the Origin Path Rewrite tab in order from top to bottom. A change to this order may lead to a different rewrite result.

• Origin Path Rewrite may conflict with the settings of the Ignore Parameters feature in Domain Names>Optimization. Make sure that the features do not conflict with each other.

Differences between access URL rewrite and origin path rewrite

Access URL rewriting

1. A client sends a request to a POP. The request URL is old.example.com/hello.

2. After the POP receives the request, it rewrites the request URL to new.example.com/hello based on the access URL rewrite rule. The POP then includes the new URL in the HTTP Location header of the 302 response.

3. After the client receives the 302 response, it sends a new request to the new URL.

4. The POP checks its cache. If the content for the rewritten URL is cached, the POP returns the content to the client. If the content is not cached, the POP sends a request to the origin server. The request URL is the rewritten URL, new.example.com/hello.

5. The origin server receives the request and returns the response to the POP.

6. The POP caches the response and returns it to the client.

Origin path rewriting

1. A client sends a request to a POP. The request URL is cdn.example.com/files/hello.txt.

2. After the POP receives the request, it checks its cache. If the content for the request URL is cached, the POP returns the content to the client. If the content is not cached, the POP rewrites the origin path to origin.example.com/secret/files/hello.txt based on the origin path rewrite rule and sends a request to the origin server.

3. The origin server receives the request and returns the response to the POP.

4. The POP caches the response and returns it to the client.

Create an origin path rewrite rule

1. Log on to the CDN console.

2. In the left navigation pane, click Domain Names.

3. On the Domain Names page, find the target domain name and click Manage in the Actions column.

4. In the left-side navigation tree of the domain name, click Origin Fetch.

5. Click the Origin Path Rewrite tab.

6. Click Add.

7. Configure the Path to Be Rewritten, Target Path, and Flag parameters. The following table describes the parameters.

   

   Parameter	Example	Description
   Path to Be Rewritten	^/hello$	Enter a URL that starts with a forward slash (/). The URL cannot contain http:// or domain names. You must use Perl Compatible Regular Expressions (PCRE).
   Target Path	/hello/test	Enter a URL that starts with a forward slash (/). The URL cannot contain http:// or domain names. PCRE is supported.
   Flag	None	If you configure multiple URL rewrite rules, Alibaba Cloud CDN matches requests against the rules in order from top to bottom.
   	break	If you configure multiple URL rewrite rules, and the current rule is matched, other rules are skipped. This option rewrites only the resource path in the URL. The URL parameters remain unchanged. You can use the parameter rewrite feature to rewrite URL parameters.Origin Path Rewrite
   	enhance break	If you configure multiple URL rewrite rules, and the current rule is matched, other rules are skipped. Compared with break, enhance break also rewrites URL parameters. However, the parameter rewrite settings may conflict with the settings of Rewrite origin fetch parameters. If you want to enable both features, make sure that the settings do not conflict with each other.

8. Click OK to apply the rule.

   The new rewrite rule is displayed on the Origin Path Rewrite tab. You can click Modify or Delete in the Actions column of the rewrite rule to modify or delete the rewrite rule.

Configuration examples

• Example 1: Apply a rule whose flag is set to None.

  Path to Be Rewritten	^/hello$
  Target Path	/index.html
  Flag	None
  Expected result	Original request: http://example.com/hello Final request: http://example.com/index.html The system continues to match the request against other URL rewrite rules that are listed on the Origin Path Rewrite tab.

• Example 2: Apply a rule whose flag is set to Break.

  Path to Be Rewritten	^/hello.jpg$
  Target Path	/image/hello.jpg
  Flag	break
  Expected result	Original request: http://example.com/hello.jpg Final request: http://example.com/image/hello.jpg The system stops matching the request against other URL rewrite rules that are listed on the Origin Path Rewrite tab.

• Example 3: Apply a rule whose flag is set to enhance break.

  Path to Be Rewritten	^/hello.jpg?code=123$
  Target Path	/image/hello.jpg?code=321
  Flag	enhance break
  Expected result	Original request: http://example.com/hello.jpg?code=123 Final request: http://example.com/image/hello.jpg?code=321 The system stops matching the request against other URL rewrite rules that are listed on the Origin Path Rewrite tab.

• Example 4: Add a URL prefix to the root directory if the file name is a variable

  Add the /image path to the URLs of all files in the root directory. For example, rewrite /xxx in URLs to /image/xxx. In this example, xxx is a file name, such as hello.jpg or hello.html.

  Path to Be Rewritten	^(.*)$ Note ^ matches a string from the beginning of the string. (.*) is a group, in which . matches any character except a line feed. * matches the preceding character or group zero or more times. You can use $1 in the target path to reference the variable content of the group. $ matches a string to the end of the string. ^(.*)$ matches a string from the beginning to the end of the string, which can contain any character except a line break, and then captures the matched content into a group. For example, for a string "hello world", ^(.*)$ matches the entire string and captures "hello world" into the first group.
  Target Path	/image$1 Note /image matches the string "/image". $1 references the content of the first group, $2 references the content of the second group, and so forth. /image$1 matches the string "/image" followed by the content of the first group. For example, if the content of the first group is "abc", /image$1 matches the string "/imageabc". Note that the $1 references the content of the group instead of the literal "$1". If you want to match the literal "$1", use the escaped string "\$1".
  Flag	break
  Expected result	Original request: http://example.com/hello.jpg Final request: http://example.com/image/hello.jpg Original request: http://example.com/hello.html Final request: http://example.com/image/hello.html The system stops matching the request against other URL rewrite rules that are listed on the origin path Rewrite tab.

• Example 5: Add a URL prefix to a specific directory if the file name is a variable.

  Add the /image path to the URLs of all files in the /live directory. For example, rewrite /live/xxx in URLs to /image/live/xxx. In this example, xxx is a file name, such as hello.jpg or hello.html.

  Path to Be Rewritten	^/live/(.*)$
  Target Path	/image/live/$1
  Flag	break
  Expected result	Original request: http://example.com/live/hello.jpg Final request: http://example.com/image/live/hello.jpg Original request: http://example.com/live/hello.html Final request: http://example.com/image/live/hello.html The system stops matching the request against other URL rewrite rules that are listed on the origin path Rewrite tab.

• Example 6: Apply only the rule whose flag is set to None when multiple rules are configured.

  Create two URL rewrite rules, as shown in the following figure.

  Expected result:

  • Original request: http://example.com/image_01.png

  • Final request: http://example.com/image/image_02.png

    Note

    The request matches the first rule and the origin path is rewritten to http://example.com/image_02.png. Then, the request matches the second rule and the origin path is rewritten to http://example.com/image/image_02.png.

• Example 7: Apply the rule whose flag is set to Break when multiple rules are configured.

  Create two URL rewrite rules, as shown in the following figure.

  Expected result:

  • Original request: http://example.com/image_01.png

  • Final request: http://example.com/image_02.png

    Note

    The request matches the first rule and the request URL is rewritten to http://example.com/image_02.png. Other rules are skipped.