Ignore parameters - Edge Security Acceleration - Alibaba Cloud Documentation Center

Parameters in a URL request that follow the ? can affect the cache hit ratio. When you enable the ignore parameter feature, DCDN points of presence (POPs) remove the parameters that follow the ? from the URL when matching content in the cache. This increases the cache hit ratio and reduces the number of back-to-origin requests.

Usage notes

Feature conflicts

Important

The Custom Cachekey and ignore parameter features conflict. Do not enable both features at the same time.

When the ignore parameter feature is enabled, DCDN POPs modify the parameters in the cache key for both the Retain Specified Parameters and Delete Specified Parameters modes. As a result, the request parameter settings in the Custom Cachekey feature will have no effect.

To use Custom Cachekey for cache key configuration, disable the ignore parameter feature.

Use Custom Cachekey as an alternative

The Custom Cachekey feature includes all the functionality of the ignore parameter feature but offers more flexible parameter control. We recommend using Custom Cachekey instead. The following table compares the configurations.

Use case	Ignore parameter configuration	Custom Cachekey configuration
Ignore all request parameters in the cache key.	Set Passed to Yes and leave the Retain Specified Parameters field empty.	Add a request parameter handling policy: set the operation to Yes and the parameter name to any non-existent parameter name.
Retain only the request parameter `key1` in the cache key.	Set Ignore Parameter to Passed and Retain Specified Parameters to `key1`	Add a request parameter handling rule: set the operation to Yes and the parameter name to `key1`.
Delete only the request parameter `key1` from the cache key.	Delete Specified Parameters is set to `key1`	Add a request parameter handling policy: set Action to Delete and Parameter Name to `key1`

How it works

The ignore parameter feature provides two functions: parameter filtering and retention of parameters for back-to-origin requests.

Parameter filtering

If this feature is enabled, a DCDN point of presence (POP) removes the parameters that follow the ? from a URL when performing a cache lookup. This allows requests for the same resource with different parameters to hit the same cached file.

Scenario	Description
A URL contains parameters such as user IDs that are irrelevant to the resource content.	For example, User A requests `http://example.com/1.jpg?uid=123` and User B requests `http://example.com/1.jpg?uid=654`. If you enable the ignore parameter feature, the DCDN POP uses `http://example.com/1.jpg` for the cache lookup. This allows both requests to hit the same cached file.

Retention of parameters for back-to-origin requests

Scenario	Description
You enable parameter filtering and need to pass user information to the origin server.	If you enable the ignore parameter setting, DCDN by default uses the URL with its parameters removed for back-to-origin requests. If you enable Retain Origin Parameters, DCDN uses the original URL, including the parameters that follow the `?`, for back-to-origin requests to pass user information to the origin server.

Note

The URL signing feature takes precedence over the ignore parameter feature. When Type A signing is used, the signing information is in the request parameters. DCDN authenticates the request first. After successful authentication, DCDN caches the resource on a DCDN POP. For more information about how to configure URL signing, see Configure URL signing.

Procedure

Log on to the DCDN console.
In the left-side navigation pane, click Domain Names.
On the Domain Names page, find the domain name that you want to manage and click Configure.
In the left-side navigation tree of the domain name, click Optimization.

In the Ignore Parameters section, click Modify. Then, select a mode and configure the parameters based on your business needs.

Note

If you switch between modes, the existing settings are deleted.

Mode: Retain Specified Parameters

Parameter	Description	Example
Parameter Filtering	Passed: removes the parameters that follow the `?` from the URL to improve the cache hit ratio. Note If you configure only Ignore Parameter and do not set Retain Specified Parameters, all parameters after the `?` character are removed. Rejected: The parameters that follow the `?` in the URL must match exactly.	Assume that the original URL is `http://example.com/1.jpg?key1=1&key2=2&key3=3`. Ignore all parameters and use the processed URL for back-to-origin requests Settings: Set Parameter Filtering to Passed, leave the Retain Specified Parameters field empty, and set Retain Origin Parameters to Rejected. Cache key: `http://example.com/1.jpg` Back-to-origin URL: `http://example.com/1.jpg` Retain specified parameters and use the processed URL for back-to-origin requests Settings: Set Parameter Filtering to Passed, set Retain Specified Parameters to `key1`, and set Retain Origin Parameters to Rejected. Cache key: `http://example.com/1.jpg?key1=1` Back-to-origin URL: `http://example.com/1.jpg?key1=1` Ignore all parameters and use the original URL for back-to-origin requests Settings: Set Parameter Filtering to Passed, leave the Retain Specified Parameters field empty, and set Retain Origin Parameters to Passed. Cache key: `http://example.com/1.jpg` Back-to-origin URL: `http://example.com/1.jpg?key1=1&key2=2&key3=3` Retain specified parameters and use the original URL for back-to-origin requests Settings: Set Parameter Filtering to Passed, set Retain Specified Parameters to `key1`, and set Retain Origin Parameters to Passed. Cache key: `http://example.com/1.jpg?key1=1` Back-to-origin URL: `http://example.com/1.jpg?key1=1&key2=2&key3=3`
Retain Specified Parameters	Specify the parameters to retain. You can specify up to 10 parameters, separated by commas (`,`).	After you set Retain Specified Parameters to `key1`, only the `key1` parameter in the URL is retained for cache matching.
Retain Origin Parameters	Passed: All parameters from the original URL are retained in back-to-origin requests. Rejected: The parameters for back-to-origin requests match those in the cache key, meaning only the specified parameters are retained.	For more information, compare the back-to-origin URLs in the second and fourth examples in the Example column.

Mode: Delete Specified Parameters

Parameter

Description

Example

Delete Specified Parameters

Specify the parameters to delete. You can specify up to 10 parameters, separated by spaces.

Assume that the original URL is http://example.com/1.jpg?key1=1&key2=2&key3=3.

Delete specified parameters and use the processed URL for back-to-origin requests
Settings: Set Delete Specified Parameters to key1 and set Retain Origin Parameters to Rejected.
Cache key: http://example.com/1.jpg?key2=2&key3=3
Back-to-origin URL: http://example.com/1.jpg?key2=2&key3=3
Delete specified parameters and use the original URL for back-to-origin requests
Settings: Set Delete Specified Parameters to key1 and set Retain Origin Parameters to Passed.
Cache key: http://example.com/1.jpg?key2=2&key3=3
Back-to-origin URL: http://example.com/1.jpg?key1=1&key2=2&key3=3

Retain Origin Parameters

Passed: All parameters from the original URL are retained in back-to-origin requests.
Rejected: The parameters for back-to-origin requests match those in the cache key, meaning the specified parameters are deleted.

For more information, see the difference in the back-to-origin URL between Scenario 1 and Scenario 2.

Click OK.