网络请求框架使用的retrofit，客户端与服务端之间需要加密通信并且请求需要gzip压缩。为完成这一需求，需要拦截请求和响应。特此记录下修改请求的过程，希望可以帮助有需要的人。
处理request
retrofit2使用okhttp3.x，请求上的处理只需要给okhttp添加拦截器即可
这里与服务端通信相互之间对称加密，并且需要开启gzip压缩，因此这里定义了三个拦截器完成这一需求
-
修改请求头
public class RequestHeaderInterceptor implements Interceptor { @Override public Response intercept(Chain chain) throws IOException { Request originalRequest = chain.request(); Request updateRequest = originalRequest.newBuilder() .header("Content-Type", "text/plain; charset=utf-8") .header("Accept", "*/*") .header("Accept-Encoding", "gzip") .build(); return chain.proceed(updateRequest); } } -
加密请求内容
public class RequestEncryptInterceptor implements Interceptor { @Override public Response intercept(Chain chain) throws IOException { Request request = chain.request(); RequestBody body = request.body(); Buffer buffer = new Buffer(); body.writeTo(buffer); Charset charset = Charset.forName("UTF-8"); MediaType contentType = body.contentType(); if (contentType != null) { charset = contentType.charset(charset); } String paramsStr = buffer.readString(charset); try { paramsStr = EncryptUtils.encryptParams(paramsStr); } catch (Exception e) { LogUtils.e(e); } RequestBody requestBody = RequestBody.create(MediaType.parse("text/plain; charset=utf-8"), paramsStr); request = request.newBuilder() .post(requestBody) .build(); return chain.proceed(request); } } -
启用Gzip压缩
public class GzipRequsetInterceptor implements Interceptor { @Override public Response intercept(Chain chain) throws IOException { Request originalRequest = chain.request(); if (originalRequest.body() == null || originalRequest.header("Content-Encoding") != null) { return chain.proceed(originalRequest); } Request compressedRequest = originalRequest.newBuilder() .header("Content-Encoding", "gzip") .method(originalRequest.method(), gzip(originalRequest.body())) .build(); return chain.proceed(compressedRequest); } private RequestBody gzip(final RequestBody body) { return new RequestBody() { @Override public MediaType contentType() { return body.contentType(); } @Override public long contentLength() throws IOException { return -1; } @Override public void writeTo(BufferedSink sink) throws IOException { BufferedSink gzipSink = Okio.buffer(new GzipSink(sink)); body.writeTo(gzipSink); gzipSink.close(); } }; } }
处理response
对response处理需要未retrofit设置自定义的ConverterFactory，因客户端与服务端使用json通信，因此我们参考官方提供GsonConverterFactory编写
自定义GsonConverterFactory，其实相对于原版只修改了responseBodyConverter方法的内容，requestBodyConverter依旧用的原版内容。
注意,
GsonRequestBodyConverter类的修饰符不是public，需要将其代码拷贝出来
public final class CustomGsonConverterFactory extends Converter.Factory {
private final Gson gson;
public static CustomGsonConverterFactory create() {
return create(new Gson());
}
@SuppressWarnings("ConstantConditions") // Guarding public API nullability.
public static CustomGsonConverterFactory create(Gson gson) {
if (gson == null) throw new NullPointerException("gson == null");
return new CustomGsonConverterFactory(gson);
}
private CustomGsonConverterFactory(Gson gson) {
this.gson = gson;
}
@Override
public Converter<ResponseBody, ?> responseBodyConverter(Type type, Annotation[] annotations, Retrofit retrofit) {
TypeAdapter<?> adapter = gson.getAdapter(TypeToken.get(type));
return new CustomGsonResponseConverter<>(gson, adapter);
}
@Override
public Converter<?, RequestBody> requestBodyConverter(Type type, Annotation[] parameterAnnotations, Annotation[] methodAnnotations, Retrofit retrofit) {
TypeAdapter<?> adapter = gson.getAdapter(TypeToken.get(type));
return new GsonRequestBodyConverter<>(gson, adapter);
}
}
修改GsonResponseConverter，使其解密后再处理内容。
注意：这里预处理json的过程并非通用步骤，因我的json格式是
{ "code": 0, "message": "success", "data": { ... } }这样的，如果你的不同请换一种方式。
class CustomGsonResponseConverter<T> implements Converter<ResponseBody, T> {
private final Gson gson;
private final TypeAdapter<T> adapter;
CustomGsonResponseConverter(Gson gson, TypeAdapter<T> adapter) {
this.gson = gson;
this.adapter = adapter;
}
@Override
public T convert(ResponseBody value) throws IOException {
try {
String originalBody = value.string();
// 解密
String body = EncryptUtils.decryptParams(originalBody);
// 获取json中的code，对json进行预处理
JSONObject json = new JSONObject(body);
int code = json.optInt("code");
// 当code不为0时，设置data为{}，这样转化就不会出错了
if (code != 0) {
json.put("data", new JSONObject());
body = json.toString();
}
return adapter.fromJson(body);
} catch (Exception e) {
throw new RuntimeException(e.getMessage());
} finally {
value.close();
}
}
这里也贴一下原版的GsonRequestBodyConverter：
class GsonRequestBodyConverter<T> implements Converter<T, RequestBody> {
private static final MediaType MEDIA_TYPE = MediaType.parse("application/json; charset=UTF-8");
private static final Charset UTF_8 = Charset.forName("UTF-8");
private final Gson gson;
private final TypeAdapter<T> adapter;
GsonRequestBodyConverter(Gson gson, TypeAdapter<T> adapter) {
this.gson = gson;
this.adapter = adapter;
}
@Override public RequestBody convert(T value) throws IOException {
Buffer buffer = new Buffer();
Writer writer = new OutputStreamWriter(buffer.outputStream(), UTF_8);
JsonWriter jsonWriter = gson.newJsonWriter(writer);
adapter.write(jsonWriter, value);
jsonWriter.close();
return RequestBody.create(MEDIA_TYPE, buffer.readByteString());
}
}
这样build.gradle中就可以删掉引入的GsonConverterFactory了
整合使用
使用方式如下
Retrofit retrofit = new Retrofit.Builder()
.client(getOkHttpClient())
.addConverterFactory(CustomGsonConverterFactory.create())
.baseUrl(BASE_URL)
.build();
其中，okhttpClient方法：
@NonNull
private OkHttpClient getOkHttpClient() {
OkHttpClient.Builder okHttpClientBuilder = new OkHttpClient.Builder();
okHttpClientBuilder.connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.writeTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.readTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
.addInterceptor(new RequestHeaderInterceptor())
.addInterceptor(new RequestEncryptInterceptor())
.addInterceptor(new GzipRequsetInterceptor());
return okHttpClientBuilder.build();
}
就酱
