设置响应缓存持续时间Set response cache duration

• 02/26/2018
• • 

本文介绍 Azure API 管理策略示例，该示例演示如何使用后端发送的 Cache-Control 标头中的 maxAge 值设置响应缓存持续时间。This article shows an Azure API management policy sample that demonstrates how to set response cache duration using maxAge value in Cache-Control header sent by the backend. 若要设置或编辑策略代码，请执行设置或编辑策略中所述的步骤。To set or edit a policy code, follow the steps described in Set or edit a policy. 若要查看其他示例，请参阅策略示例。To see other examples, see policy samples.

策略Policy

将代码粘贴到“入站”块中。Paste the code into the inbound block.

<!-- This snippet demonstrates how to set response cache duration using maxAge value in Cache-Control header sent by the backend. -->

<!-- Copy the following snippet into the outbound section. -->
      
<policies>
  <inbound>
    <base />
  </inbound>
  <backend>
    <base />
  </backend>
  <outbound>
    <base />
    <!-- The following policy can be tested by setting up an API and operation mapped to GET http://httpbin.org/cache/{duration} -->
    <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;
        }"
     />
  </outbound>
  <on-error>
    <base />
  </on-error>
</policies>

后续步骤Next steps

了解有关 APIM 策略的详细信息：Learn more about APIM policies:

• 转换策略Transformation policies
• 策略示例Policy samples