OkHttp拦截器之获取Response.body的内容

冷不防 2023-10-17 07:53 29阅读 0赞

### 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");
        }
    }