Integrate an HTTP client

Integrate OkHttp

To integrate OkHttp with AHAS traffic protection, you can register the AHAS Sentinel interceptor when you create an OkHttpClient:

OkHttpClient client = new OkHttpClient.Builder()
        .addInterceptor(new SentinelOkHttpInterceptor(new SentinelOkHttpConfig()))
        .build();

When you create a SentinelOkHttpInterceptor, you can also provide custom logic for resource name parsing by defining the OkHttpResourceExtractor in SentinelOkHttpConfig. The following code provides an example:

OkHttpResourceExtractor extractor = (request, connection) -> {
    String resource = request.url().toString();
    String regex = "/okhttp/back/";
    if (resource.contains(regex)) {
        resource = resource.substring(0, resource.indexOf(regex) + regex.length()) + "{id}";
    }
    return resource;
};

By default, a RuntimeException("SentinelBlockException") is thrown when access to a URL is throttled. You can also provide a custom fallback handler when you create a SentinelOkHttpConfig. The following code shows an example of a fallback handler:

public class SomeFallback implements OkHttpFallback {

    @Override
    public Response handle(Request request, Connection connection, BlockException e) {
        // Construct the response for a throttled request here.
        return new Response(myErrorBuilder);
    }
}

Integrate Apache HttpClient

To integrate Apache HttpClient with AHAS traffic protection, you can use SentinelApacheHttpClientBuilder to construct the CloseableHttpClient:

HttpClientBuilder builder = new SentinelApacheHttpClientBuilder(config); // Use this builder like a normal builder. You can pass in custom configurations.
CloseableHttpClient httpClient = builder.build();

You can use SentinelApacheHttpClientBuilder in the same way that you use a normal HttpClientBuilder and pass in custom HTTP client configurations. By default, AHAS extracts the HTTP method and URL to create a resource name. The resource name uses the httpclient:${httpMethod}:${url} pattern, such as httpclient:GET:http://localhost:8088/hello.

When you create a SentinelApacheHttpClientBuilder, you can also customize the resource name parsing logic (extractor) in SentinelApacheHttpClientConfig.

By default, a RuntimeException("SentinelBlockException") is thrown when access to a URL is throttled. You can also provide a custom fallback handler when you create a SentinelApacheHttpClientConfig. The following code shows an example of a fallback handler:

public class MyApacheHttpClientFallback implements ApacheHttpClientFallback {

    @Override
    public CloseableHttpResponse handle(HttpRequestWrapper request, BlockException e) {
        // Construct the response for a throttled request here.
    }
}

References

The following documents provide more information about connecting applications to AHAS Application Protection:

• Connect a Spring Boot/Spring Cloud application

• Connect a Spring application

• Connect a Dubbo application

• Connect an HSF application

• Connect a web application

• Connect using custom instrumentation

• Connect a MyBatis application