源码系列–OkHttp（CallServerInterceptor） -云博客

源码系列–OkHttp（CallServerInterceptor）

# 前端 2024-05-05 04:46 0 24 来源：云博客

Github下载源码地址https://github.com/square/okhttp

我们今天来看看拦截器里的CallServerInterceptor

来看CallServerInterceptor类的intercept方法

1）源码：

Exchange exchange = realChain.exchange();Request request = realChain.request();

RealInterceptorChain类分别返回Exchange和Request对象

2）源码

exchange.writeRequestHeaders(request)

进到Exchange类

public void writeRequestHeaders(Request request) throws IOException { try { eventListener.requestHeadersStart(call); codec.writeRequestHeaders(request); eventListener.requestHeadersEnd(call, request); } catch (IOException e) { eventListener.requestFailed(call, e); trackFailure(e); throw e; }}

进到ExchangeCodec的实现类Http1ExchangeCodec（Http1.1版本）的writeRequestHeaders方法

@Override public void writeRequestHeaders(Request request) throws IOException { String requestLine = RequestLine.get( request, realConnection.route().proxy().type()); writeRequest(request.headers(), requestLine);}

进到RequestLine的get方法

public static String get(Request request, Proxy.Type proxyType) { StringBuilder result = new StringBuilder(); result.append(request.method()); result.append(‘ ‘); if (includeAuthorityInRequestLine(request, proxyType)) { result.append(request.url()); } else { result.append(requestPath(request.url())); } result.append(" HTTP/1.1"); return result.toString();}

这里是一些字符串的拼接和请求的判断

紧接着是Http1ExchangeCodec的writeRequest方法

public void writeRequest(Headers headers, String requestLine) throws IOException { if (state != STATE_IDLE) throw new IllegalStateException("state: " + state); sink.writeUtf8(requestLine).writeUtf8("\r\n"); for (int i = 0, size = headers.size(); i < size; i++) { sink.writeUtf8(headers.name(i)) .writeUtf8(": ") .writeUtf8(headers.value(i)) .writeUtf8("\r\n"); } sink.writeUtf8("\r\n"); state = STATE_OPEN_REQUEST_BODY;}

可以看到是通过Okio的BufferedSink实现的

Exchange类的writeRequestHeaders方法的catch中的trackFailure会走失败流程，输出ErrorCode

3）源码

responseBuilder = exchange.readResponseHeaders(true);

进到Exchange类的readResponseHeaders方法，然后再进到Http1ExchangeCodec类的readResponseHeaders方法

看名字都知道是读响应头信息，进到StatusLine的parse方法里

4）源码

BufferedSink bufferedRequestBody = Okio.buffer( exchange.createRequestBody(request, true));

最终进到Http1ExchangeCodec类的createRequestBody方法中

5）CallServerInterceptor类的intercept方法最后是生成response

源码：

Response response = responseBuilder .request(request) .handshake(exchange.connection().handshake()) .sentRequestAtMillis(sentRequestMillis) .receivedResponseAtMillis(System.currentTimeMillis()) .build();int code = response.code();if (code == 100) { // server sent a 100-continue even though we did not request one. // try again to read the actual response response = exchange.readResponseHeaders(false) .request(request) .handshake(exchange.connection().handshake()) .sentRequestAtMillis(sentRequestMillis) .receivedResponseAtMillis(System.currentTimeMillis()) .build(); code = response.code();}exchange.responseHeadersEnd(response);if (forWebSocket && code == 101) { // Connection is upgrading, but we need to ensure interceptors see a non-null response body. response = response.newBuilder() .body(Util.EMPTY_RESPONSE) .build();} else { response = response.newBuilder() .body(exchange.openResponseBody(response)) .build();}