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(!HttpHeader.hasBody(response)){
//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");
}
}