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Store to cache

  • Artikkeli

APPLIES TO: All API Management tiers

The cache-store policy caches responses according to the specified cache settings. 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 Get from 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

<cache-store duration="seconds" cache-response="true | false" />

Attributes

Attribute Description Required Default
duration Time-to-live of the cached entries, specified in seconds. Policy expressions are allowed. Yes N/A
cache-response Set to true to cache the current HTTP response. If the attribute is omitted, only HTTP responses with the status code 200 OK are cached. Policy expressions are allowed. No false

Usage

Usage notes

  • API Management only caches responses to HTTP GET requests.
  • This policy can only be used once in a policy section.

Examples

Example with corresponding cache-lookup policy

<policies>
    <inbound>
        <base />
        <cache-lookup vary-by-developer="false" vary-by-developer-groups="false" downstream-caching-type="none" must-revalidate="true" caching-type="internal" >
            <vary-by-query-parameter>version</vary-by-query-parameter>
        </cache-lookup>
    </inbound>
    <outbound>
        <cache-store duration="seconds" />
        <base />
    </outbound>
</policies>

Example using policy expressions

This 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.

<!-- The following cache policy snippets demonstrate how to control API Management response cache duration with Cache-Control headers sent by the backend service. -->

<!-- Copy this snippet into the inbound section -->
<cache-lookup vary-by-developer="false" vary-by-developer-groups="false" downstream-caching-type="public" must-revalidate="true" >
  <vary-by-header>Accept</vary-by-header>
  <vary-by-header>Accept-Charset</vary-by-header>
</cache-lookup>

<!-- Copy this snippet into the outbound section. Note that cache duration is set to the max-age value provided in the Cache-Control header received from the backend service or to the default value of 5 min if none is found  -->
<cache-store duration="@{
    var header = context.Response.Headers.GetValueOrDefault("Cache-Control","");
    var maxAge = Regex.Match(header, @"max-age=(?<maxAge>\d+)").Groups["maxAge"]?.Value;
    return (!string.IsNullOrEmpty(maxAge))?int.Parse(maxAge):300;
  }"
 />

For more information, see Policy expressions and Context variable.

Related content

For more information about working with policies, see: