OkHttp拦截器之获取Response.body的内容

OkHttp拦截器之获取Response.body的内容

项目中，由于使用了cookie，约定的有效期是20分钟，所以有可以会遇到cookie失效，无权操作，需要再次登录的情况。
在每个地方都进行无权操作error的处理显得不现实，于是就想到了使用拦截器。

但是当使用拦截器获取Response.body.string()后，后面的操作就直接返回Failed了，估计是因为流只能被使用一次的原因。

@Override
public Response intercept(Chain chain) throws IOException {

        Request request = chain.request();
        Response response = chain.proceed(request);
       
   		L.i("response.body.string:" + response.body().string());
       
		return response;	
}

后来，想到设置的 HttpLoggingInterceptor() 拦截器是如何获取到response的body的数据呢 ?

OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(new HttpLoggingInterceptor()
                        .setLevel(HttpLoggingInterceptor.Level.BODY))
						.build();  

于是乎是看了HttpLoggingInterceptor的源码

public final class HttpLoggingInterceptor implements Interceptor {
  private static final Charset UTF8 = Charset.forName("UTF-8");

  @Override public Response intercept(Chain chain) throws IOException {
    Level level = this.level;

    Request request = chain.request();

	//如果Log Level 级别为NONOE，则不打印，直接返回
    if (level == Level.NONE) {
      return chain.proceed(request);
    }

	//是否打印body
    boolean logBody = level == Level.BODY;
    //是否打印header
	boolean logHeaders = logBody || level == Level.HEADERS;

	//获得请求body
    RequestBody requestBody = request.body();
	//请求body是否为空
    boolean hasRequestBody = requestBody != null;

	//获得Connection，内部有route、socket、handshake、protocol方法
    Connection connection = chain.connection();
	//如果Connection为null，返回HTTP_1_1，否则返回connection.protocol()
    Protocol protocol = connection != null ? connection.protocol() : Protocol.HTTP_1_1;
	//比如: --> POST http://121.40.227.8:8088/api http/1.1
    String requestStartMessage = "--> " + request.method() + ' ' + request.url() + ' ' + protocol;
    if (!logHeaders && hasRequestBody) {
      requestStartMessage += " (" + requestBody.contentLength() + "-byte body)";
    }
    logger.log(requestStartMessage);

	//打印 Request
    if (logHeaders) {
      if (hasRequestBody) {
        // Request body headers are only present when installed as a network interceptor. Force
        // them to be included (when available) so there values are known.
        if (requestBody.contentType() != null) {
          logger.log("Content-Type: " + requestBody.contentType());
        }
        if (requestBody.contentLength() != -1) {
          logger.log("Content-Length: " + requestBody.contentLength());
        }
      }

      Headers headers = request.headers();
      for (int i = 0, count = headers.size(); i < count; i++) {
        String name = headers.name(i);
        // Skip headers from the request body as they are explicitly logged above.
        if (!"Content-Type".equalsIgnoreCase(name) && !"Content-Length".equalsIgnoreCase(name)) {
          logger.log(name + ": " + headers.value(i));
        }
      }

      if (!logBody || !hasRequestBody) {
        logger.log("--> END " + request.method());
      } else if (bodyEncoded(request.headers())) {
        logger.log("--> END " + request.method() + " (encoded body omitted)");
      } else {
        Buffer buffer = new Buffer();
        requestBody.writeTo(buffer);

		//编码设为UTF-8
        Charset charset = UTF8;
        MediaType contentType = requestBody.contentType();
        if (contentType != null) {
          charset = contentType.charset(UTF8);
        }

        logger.log("");
        if (isPlaintext(buffer)) {
          logger.log(buffer.readString(charset));
          logger.log("--> END " + request.method()
              + " (" + requestBody.contentLength() + "-byte body)");
        } else {
          logger.log("--> END " + request.method() + " (binary "
              + requestBody.contentLength() + "-byte body omitted)");
        }
      }
    }

	//打印 Response
    long startNs = System.nanoTime();
    Response response;
    try {
      response = chain.proceed(request);
    } catch (Exception e) {
      logger.log("<-- HTTP FAILED: " + e);
      throw e;
    }
    long tookMs = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNs);

    ResponseBody responseBody = response.body();
    long contentLength = responseBody.contentLength();
    String bodySize = contentLength != -1 ? contentLength + "-byte" : "unknown-length";
	//比如 <-- 200 OK http://121.40.227.8:8088/api (36ms)
    logger.log("<-- " + response.code() + ' ' + response.message() + ' '
        + response.request().url() + " (" + tookMs + "ms" + (!logHeaders ? ", "
        + bodySize + " body" : "") + ')');

    if (logHeaders) {
      Headers headers = response.headers();
      for (int i = 0, count = headers.size(); i < count; i++) {
        logger.log(headers.name(i) + ": " + headers.value(i));
      }

      if (!logBody || !HttpEngine.hasBody(response)) {
        logger.log("<-- END HTTP");
      } else if (bodyEncoded(response.headers())) {
        logger.log("<-- END HTTP (encoded body omitted)");
      } else {
        BufferedSource source = responseBody.source();
        source.request(Long.MAX_VALUE); // Buffer the entire body.
        Buffer buffer = source.buffer();

        Charset charset = UTF8;
        MediaType contentType = responseBody.contentType();
        if (contentType != null) {
          try {
            charset = contentType.charset(UTF8);
          } catch (UnsupportedCharsetException e) {
            logger.log("");
            logger.log("Couldn't decode the response body; charset is likely malformed.");
            logger.log("<-- END HTTP");

            return response;
          }
        }

        if (!isPlaintext(buffer)) {
          logger.log("");
          logger.log("<-- END HTTP (binary " + buffer.size() + "-byte body omitted)");
          return response;
        }

        if (contentLength != 0) {
          logger.log("");
			
		  //获取Response的body的字符串 并打印
          logger.log(buffer.clone().readString(charset));
        }

        logger.log("<-- END HTTP (" + buffer.size() + "-byte body)");
      }
    }

    return response;
  }

  /**
   * Returns true if the body in question probably contains human readable text. Uses a small sample
   * of code points to detect unicode control characters commonly used in binary file signatures.
   */
  static boolean isPlaintext(Buffer buffer) throws EOFException {
    try {
      Buffer prefix = new Buffer();
      long byteCount = buffer.size() < 64 ? buffer.size() : 64;
      buffer.copyTo(prefix, 0, byteCount);
      for (int i = 0; i < 16; i++) {
        if (prefix.exhausted()) {
          break;
        }
        int codePoint = prefix.readUtf8CodePoint();
        if (Character.isISOControl(codePoint) && !Character.isWhitespace(codePoint)) {
          return false;
        }
      }
      return true;
    } catch (EOFException e) {
      return false; // Truncated UTF-8 sequence.
    }
  }

  private boolean bodyEncoded(Headers headers) {
    String contentEncoding = headers.get("Content-Encoding");
    return contentEncoding != null && !contentEncoding.equalsIgnoreCase("identity");
  }
}

然后，根据HttpLoggingInterceptor，就很容易得到responsebody的内容了

/**
 * @Description 异常处理 拦截器
 * Created by EthanCo on 2016/7/14.
 */
public class ErrorHandlerInterceptor implements Interceptor {
    private static final Charset UTF8 = Charset.forName("UTF-8");

    @Override
    public Response intercept(Chain chain) throws IOException {

        Request request = chain.request();
        Response response = chain.proceed(request);

        ResponseBody responseBody = response.body();
        long contentLength = responseBody.contentLength();
        
        //注意 >>>>>>>>> okhttp3.4.1这里变成了 !HttpHeader.hasBody(response)
        //if (!HttpEngine.hasBody(response)) { 
        if(!HttpHeaders.hasBody(response)){ //HttpHeader -> 改成了 HttpHeaders，看版本进行选择
		    //END HTTP
        } else if (bodyEncoded(response.headers())) {
            //HTTP (encoded body omitted)
        } else {
            BufferedSource source = responseBody.source();
            source.request(Long.MAX_VALUE); // Buffer the entire body.
            Buffer buffer = source.buffer();

            Charset charset = UTF8;
            MediaType contentType = responseBody.contentType();
            if (contentType != null) {
                try {
                    charset = contentType.charset(UTF8);
                } catch (UnsupportedCharsetException e) {
                    //Couldn't decode the response body; charset is likely malformed.
                    return response;
                }
            }

            if (!isPlaintext(buffer)) {
                L.i("<-- END HTTP (binary " + buffer.size() + "-byte body omitted)");
                return response;
            }

            if (contentLength != 0) {
                String result = buffer.clone().readString(charset);
                
				//获取到response的body的string字符串
				//do something .... <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
            }

            L.i("<-- END HTTP (" + buffer.size() + "-byte body)");
        }
        return response;
    }
	   
    static boolean isPlaintext(Buffer buffer) throws EOFException {
        try {
            Buffer prefix = new Buffer();
            long byteCount = buffer.size() < 64 ? buffer.size() : 64;
            buffer.copyTo(prefix, 0, byteCount);
            for (int i = 0; i < 16; i++) {
                if (prefix.exhausted()) {
                    break;
                }
                int codePoint = prefix.readUtf8CodePoint();
                if (Character.isISOControl(codePoint) && !Character.isWhitespace(codePoint)) {
                    return false;
                }
            }
            return true;
        } catch (EOFException e) {
            return false; // Truncated UTF-8 sequence.
        }
    }

    private boolean bodyEncoded(Headers headers) {
        String contentEncoding = headers.get("Content-Encoding");
        return contentEncoding != null && !contentEncoding.equalsIgnoreCase("identity");
    }
}