Azure API Management policy reference |
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08/15/2023
Use the cache-lookup policy to perform cache lookup and return a valid cached response when available. This policy can be applied in cases where response content remains static over a period of time. Response caching reduces bandwidth and processing requirements imposed on the backend web server and lowers latency perceived by API consumers. Note This policy must have a corresponding Store to cache policy. Important Built-in cache is volatile and is shared by all units in the same region in the same API Management service. Note Set the policy's elements and child elements in the order provided in the policy statement. To help you configure this policy, the portal provides a guided, form-based editor. Learn more about how to set or edit API Management policies. Policy statement Accept Accept-Charset Authorization header name parameter name Attributes Attribute Description Required Default allow-private-response-caching When set to true, allows caching of requests that contain an Authorization header. Policy expressions are allowed. No false caching-type Choose between the following values of the attribute:- internal to use the built-in API Management cache,- external to use the external cache as described in Use an external Azure Cache for Redis in Azure API Management,- prefer-external to use external cache if configured or internal cache otherwise.Policy expressions aren't allowed. No prefer-external downstream-caching-type This attribute must be set to one of the following values.- none - downstream caching is not allowed.- private - downstream private caching is allowed.- public - private and shared downstream caching is allowed. Policy expressions are allowed. No none must-revalidate When downstream caching is enabled this attribute turns on or off the must-revalidate cache control directive in gateway responses. Policy expressions are allowed. No true vary-by-developer Set to true to cache responses per developer account that owns subscription key included in the request. Policy expressions are allowed. Yes false vary-by-developer-groups Set to true to cache responses per user group. Policy expressions are allowed. Yes false Elements Name Description Required vary-by-header Add one or more of these elements to start caching responses per value of specified header, such as Accept, Accept-Charset, Accept-Encoding, Accept-Language, Authorization, Expect, From, Host, If-Match. No vary-by-query-parameter Add one or more of these elements to start caching responses per value of specified query parameters. Enter a single or multiple parameters. Use semicolon as a separator. No Usage Policy sections: inbound Policy scopes: global, workspace, product, API, operation Gateways: dedicated, consumption, self-hosted Usage notes API Management only performs cache lookup for HTTP GET requests. When using vary-by-query-parameter, you might want to declare the parameters in the rewrite-uri template or set the attribute copy-unmatched-params to false. By deactivating this flag, parameters that aren't declared are sent to the backend. This policy can only be used once in a policy section. Examples Example with corresponding cache-store policy version Example using policy expressionsThis example shows how to configure API Management response caching duration that matches the response caching of the backend service as specified by the backend service's Cache-Control directive. Accept Accept-CharsetFor more information, see Policy expressions and Context variable. Related policies API Management caching policies Related contentFor more information about working with policies, see: Tutorial: Transform and protect your API Policy reference for a full list of policy statements and their settings Policy expressions Set or edit policies Reuse policy configurations Policy snippets repo |
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