gRPC请求中对header进行处理

gRPC请求设置header(Android、iOS、JavaServer)

1.[Android (Java)]

见类 io.grpc.stub.MetadataUtils，其中有个方法:

  /**   * Attaches a set of request headers to a stub.   *   * @param stub to bind the headers to.   * @param extraHeaders the headers to be passed by each call on the returned stub.   * @return an implementation of the stub with {@code extraHeaders} bound to each call.   */  @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1789")  public static > T attachHeaders(      T stub,      final Metadata extraHeaders) {    return stub.withInterceptors(newAttachHeadersInterceptor(extraHeaders));  }

稍微自己封装一下的效果，如下：

    private static > T attachHeaders(T stub, final Map headerMap) {        Metadata extraHeaders = new Metadata();        if (headerMap != null) {            for (String key : headerMap.keySet()) {                Metadata.Key customHeadKey = Metadata.Key.of(key, Metadata.ASCII_STRING_MARSHALLER);                extraHeaders.put(customHeadKey, headerMap.get(key));            }        }        return MetadataUtils.attachHeaders(stub, extraHeaders);    }

第一步：主要是设置http的拦截器ClientInterceptor，拦截器类大概实现代码如下：

/** * A interceptor to handle client header. * * @author Kido * @email everlastxgb@gmail.com * @create_time 2016/7/7 11:02 */class HeaderClientInterceptor implements ClientInterceptor {    private static final String TAG = "HeaderClientInterceptor";    private Map mHeaderMap;    public HeaderClientInterceptor(Map headerMap) {        mHeaderMap = headerMap;    }    @Override    public  ClientCall interceptCall(MethodDescriptor method,                                                               CallOptions callOptions, Channel next) {        return new SimpleForwardingClientCall(next.newCall(method, callOptions)) {            @Override            public void start(Listener responseListener, Metadata headers) {                /* put custom header */                if (mHeaderMap != null) {                    for (String key : mHeaderMap.keySet()) {                        Metadata.Key customHeadKey = Metadata.Key.of(key, Metadata.ASCII_STRING_MARSHALLER);                        headers.put(customHeadKey, mHeaderMap.get(key));                    }                }                Logger.i(TAG, "header send to server:" + headers);                super.start(new SimpleForwardingClientCallListener(responseListener) {                    @Override                    public void onHeaders(Metadata headers) {                        /**                         * if you don't need receive header from server,                         * you can use {@link io.grpc.stub.MetadataUtils attachHeaders}                         * directly to send header                         */                        Logger.i(TAG, "header received from server:" + headers);                        super.onHeaders(headers);                    }                }, headers);            }        };    }}

第二步：大概使用代码如下：

Map headerMap = new HashMap<>();//...ClientInterceptor interceptor = new HeaderClientInterceptor(headerMap);//...ManagedChannel managedChannel = ManagedChannelBuilder.forAddress(host, port).usePlaintext(true).build();Channel channel = ClientInterceptors.intercept(managedChannel, interceptor);// then create stub here by this channel

2. [iOS (Objective-C)]

首先，可以看到GRPCCall中有如下属性：

@property(atomic, readonly) NSDictionary *responseHeaders;@property(atomic, readonly) NSDictionary *responseTrailers;

接着，可以进行如下设置：

call.requestHeaders[@"My-Header"] = @"Value for this header";call.requestHeaders[@"Another-Header"] = @"Its value";

3.[Server (Java)]

既然是Java，实现方式应该也和上述Android大概一样。
第一步：拦截器

/** * A interceptor to handle server header. */public class HeaderServerInterceptor implements ServerInterceptor {  private static final Logger logger = Logger.getLogger(HeaderServerInterceptor.class.getName());  private static Metadata.Key customHeadKey =      Metadata.Key.of("custom_server_header_key", Metadata.ASCII_STRING_MARSHALLER);  @Override  public  ServerCall.Listener interceptCall(      ServerCall call,      final Metadata requestHeaders,      ServerCallHandler next) {    logger.info("header received from client:" + requestHeaders);    return next.startCall(new SimpleForwardingServerCall(call) {      @Override      public void sendHeaders(Metadata responseHeaders) {        responseHeaders.put(customHeadKey, "customRespondValue");        super.sendHeaders(responseHeaders);      }    }, requestHeaders);  }}

第二步：使用示例

//...Server server = ServerBuilder.forPort(port)  .addService(ServerInterceptors.intercept(new GreeterImpl(), new HeaderServerInterceptor()))  .build()  .start();//...

gRPC请求设置header(Android、iOS、JavaServer)

1.[Android (Java)]

1.1只设置客户端请求时附带的header

1.2 支持设置客户端请求的header以及获取服务端返回结果中的header

2. [iOS (Objective-C)]

3.[Server (Java)]

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