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Overview

Use this policy to save time when network is congested and proxy API response is delayed. An incoming HTTP request to one of your Proxy endpoints returns the cached response after a specified time period.

In the policy settings, you specify the cache key parameters that HTTP requests map to and set the cache response time and refresh interval.

Because API Versions use endpoints generated in the SnapLogic IIP, the HTTP Response Cache policy supports Proxy endpoints only by design. In the UI, the API Policy Manager menus API and Version Details tabs do not display this policy.

Policy Execution Order

This policy executes after authentication and traffic shaping policies.

Architecture

This policy uses Google Guava cache, which offers a map to send responses. The cache must be enabled through feature flags on the Snaplex.

Protocol
Host
PAth
Method

Headers/Query params supported

Hash Key SChe1 algorithm

Each key-value pair in the Response Cache Map will be:

{
  policy_instance_id: Google Guava Cache,
  ...
}

Each Google Guava Cache has the key-value pairs:

{
  [ Hash Hex of params specified by policy ]: Cached HTTP Response
  ...
}

Each Cached HTTP Response contains the following information:

Original HTTP Response Object for preserving the flow of handling HTTP responses in the Gateway Resource.
- byte[] of the response content to preserve the stream that cannot be rewound.

Expired caches cannot be accessed and new entries overwrite any existing ones.

policy version to determine if the policy has been updated since the last save. An update to the policy will direct the flow to acquire a new HTTP response and overwrite the existing one.

Limitations

We do limit the response cache to have a response less than the MAX_CACHE_BYTES which is a feature flag default to a value of 90000000 bytes which is equivalent to 85.83 MB (edited)

Settings

Parameter Name	Description	Default Value
Label	Required. The name for the API policy.	HTTP Respone Cache
When this policy should be applied	An expression-enabled field that determines the condition to be fulfilled for the API policy to execute. For example, if the value in this field is `request.method == "POST"`, the API policy is executed only if the request method is a POST.	N/A
Cache Interval	The time period of the current cache before it is refreshed.	1
Time Unit	The time unit for the Cache Interval value.	Hour
Use HTTP Request Headers to Create Cache Keys	Enables the use of specific headers to identify a cache.	Unselected
Use HTTP Request Query Parameter to Create Cache Keys	Enables the use of query parameters to identify a cache.	Unselected
Status	Specifies whether the API policy is enabled or disabled.	Enabled