当我使用retrofit 1.4.1和okhttp 1.3.0在WS上激活gzip时，我遇到了问题。
RequestInterceptor requestInterceptor = new RequestInterceptor() {
@Override
public void intercept(RequestFacade request) {
request.addHeader("content-type", "application/json");
request.addHeader("accept-encoding", "gzip"); // Here is the problem
}
};
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint(Constants.HOST)
.setLogLevel(RestAdapter.LogLevel.FULL)
.setRequestInterceptor(requestInterceptor)
.build();
如果我评论以下行request.addHeader("accept-encoding", "gzip");没有问题但是如果激活了gzip，我会收到错误（我的请求属于failure）。
这是我的request.addHeader("accept-encoding", "gzip");
1326 Retrofit D : HTTP/1.1 200 OK
1326 Retrofit D Cache-Control: public, max-age=600
1326 Retrofit D Content-Encoding: gzip
1326 Retrofit D Content-Length: 254
1326 Retrofit D Content-Type: application/json
1326 Retrofit D Date: Wed, 05 Feb 2014 20:22:26 GMT
1326 Retrofit D OkHttp-Received-Millis: 1391631746193
1326 Retrofit D OkHttp-Response-Source: NETWORK 200
1326 Retrofit D OkHttp-Selected-Transport: http/1.1
1326 Retrofit D OkHttp-Sent-Millis: 1391631745971
1326 Retrofit D Server: Apache
1326 Retrofit D Vary: Accept-Encoding
1326 Retrofit D X-Powered-By: PHP/5.3.3-7+squeeze18
1326 Retrofit D ������������}�?O�0��~����nHZOH0 �D�ù���?���~w.�:����=�{�
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1326 Retrofit D <--- END HTTP (254-byte body)
1326 System.err W retrofit.RetrofitError: retrofit.converter.ConversionException: com.google.gson.JsonSyntaxException: java.lang.Ille
galStateException: Expected BEGIN_OBJECT but was STRING at line 1 column 1
1326 System.err W at retrofit.RestAdapter$RestHandler.invokeRequest(RestAdapter.java:408)
1326 System.err W at retrofit.RestAdapter$RestHandler.access$100(RestAdapter.java:262)
1326 System.err W at retrofit.RestAdapter$RestHandler$2.obtainResponse(RestAdapter.java:313)
1326 System.err W at retrofit.CallbackRunnable.run(CallbackRunnable.java:38)
1326 System.err W at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
1326 System.err W at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
1326 System.err W at retrofit.Platform$Android$2$1.run(Platform.java:136)
1326 System.err W at java.lang.Thread.run(Thread.java:841)
1326 System.err W Caused by: retrofit.converter.ConversionException: com.google.gson.JsonSyntaxException: java.lang.IllegalStateExcep
如何开启gzip？
提前谢谢
答案 0 :(得分：26)
只需忽略代码中的accept-encoding标头即可。 OkHttp将添加自己的accept-encoding标头，如果服务器使用gzip响应，那么OkHttp将默默地为您解压缩。
答案 1 :(得分：2)
在遇到类似的问题后（在我的情况下，没有添加任何Accept-Encoding标头，它偶尔会无法解压缩响应，还会在其中留下Content-Encoding：gzip标头，从而导致JSON解析器崩溃） ，并没有明确的方法，我通过创建下面的委托客户端实现手动启用gzip for Retrofit。它工作得很好，除了你可能不应该将它用于非常大的（例如> 250KB）响应，因为它们首先被复制到一个字节数组中。
public class GzippedClient implements Client {
private Client wrappedClient;
public GzippedClient(Client wrappedClient) {
this.wrappedClient = wrappedClient;
}
@Override
public Response execute(Request request) throws IOException {
Response response = wrappedClient.execute(request);
boolean gzipped = false;
for (Header h : response.getHeaders()) {
if (h.getName() != null && h.getName().toLowerCase().equals("content-encoding") && h.getValue() != null && h.getValue().toLowerCase().equals("gzip")) {
gzipped = true;
break;
}
}
Response r = null;
if (gzipped) {
InputStream is = null;
ByteArrayOutputStream bos = null;
try {
is = new BufferedInputStream(new GZIPInputStream(response.getBody().in()));
bos = new ByteArrayOutputStream();
int b;
while ((b = is.read()) != -1) {
bos.write(b);
}
TypedByteArray body = new TypedByteArray(response.getBody().mimeType(), bos.toByteArray());
r = new Response(response.getUrl(), response.getStatus(), response.getReason(), response.getHeaders(), body);
} finally {
if (is != null) {
is.close();
}
if (bos != null) {
bos.close();
}
}
} else {
r = response;
}
return r;
}
}
您还必须在请求中添加Accept-Encoding标头，例如通过使用RequestInterceptor
requestFacade.addHeader("Accept-Encoding", "gzip");
最后，您必须将现有客户端包装到这个新的GzpedClient中，如下所示：
restBuilder.setClient(new GzippedClient(new OkClient(okHttpClient)));
那就是它。现在您的数据将被gzip压缩。
编辑：似乎在OkHttp版本1.5.1中，一个错误（https://github.com/square/okhttp/pull/632）似乎已经修复了与透明gzipping有关，这可能（或可能不）是我的初始问题的来源。如果是这样的话，偶尔会出现un-gzip失败的情况可能不会再发生，尽管它很少发生，我还不能确认。无论哪种方式，如果你想依靠自己，而不是透明添加/删除标题和gzipping，那么所描述的解决方案将起作用。答案 2 :(得分：2)
如果你在OkHttp库中检查HttpEngine，那么你可以找到下面的代码，这意味着如果你手动将“Accept-Encoding”：“gzip”标题添加到请求中，那么un-zip是你的责任。
/**
* True if this client added an "Accept-Encoding: gzip" header field and is
* therefore responsible for also decompressing the transfer stream.
*/
private boolean transparentGzip;
所以如果你手动添加“Accept-Encoding”：“gzip”标题，那么在得到回复后，请按照下面的方式解压缩。
private static String readContentFromTypedInput(TypedInput typedInput){
InputStreamReader isr = null;
BufferedReader br = null;
char[] cbuf = new char[512];
StringWriter stringWriter = new StringWriter();
try {
final InputStream in = typedInput.in();
boolean isGzipped = GZipper.isGzippped(in);
if(isGzipped){
return new String(GZipper.doUnZip(in));
}
isr = new InputStreamReader(in);
br = new BufferedReader(isr);
while((br.read(cbuf))!= -1){
stringWriter.write(cbuf);
}
} catch (IOException e) {
throw new InvalidTestCaseException("failed read received content.", e);
} finally{
try{
if(br != null) br.close();
}catch(IOException e){
//ignore
}
}
return stringWriter.toString().trim();
}
GZipper.java
public class GZipper{
public static final String DEFAULT_CHARSET = "utf-8";
private static final int BYTE_BLOCK_LENGTH = 1024;
public static byte[] doZip(final String message){
if(message == null || message.isEmpty()){
throw new SystemFailedException("Fail to zip - given message is null or empty");
}
byte[] gzippped = null;
try {
gzippped = doZip(message.getBytes(DEFAULT_CHARSET));
} catch (Throwable e) {
throw new SystemFailedException(e.getMessage(), e);
}
return gzippped;
}
public static byte[] doZip(final byte[] unzippedMessageByte){
validate(unzippedMessageByte, "Fail to zip - given bytes is null or empty");
ByteArrayInputStream is = null;
ByteArrayOutputStream bos = null;
GZIPOutputStream gzip_os = null;
byte[] compressedBytes = null;
try{
is = new ByteArrayInputStream(unzippedMessageByte);
bos = new ByteArrayOutputStream();
gzip_os = new GZIPOutputStream(bos);
copy(is, gzip_os);
gzip_os.finish();
compressedBytes = bos.toByteArray();
}catch(IOException e){
throw new SystemFailedException(e.getMessage(), e);
}finally{
try{
if(is != null){is.close();}
if(gzip_os != null){gzip_os.close();}
if(bos != null){bos.close();}
}catch(IOException e){
//ignore
}
}
return compressedBytes;
}
public static String doUnZipToString(final byte[] gzippedMessage){
validate(gzippedMessage, "Fail to unzip - given bytes is null or empty");
byte[] gzippped = null;
String unzippedMessage = null;
try {
gzippped = doUnZip(gzippedMessage);
unzippedMessage = new String(gzippped, DEFAULT_CHARSET);
} catch (Throwable e) {
throw new SystemFailedException(e.getMessage(), e);
}
return unzippedMessage;
}
private static void validate(final byte[] bytes, String failedMessage) {
if(bytes == null || bytes.length == 0){
throw new SystemFailedException(failedMessage);
}
}
public static byte[] doUnZip(InputStream in) {
if(!(in instanceof ByteArrayInputStream)){
try {
return doUnZip(IOUtils.toByteArray(in));
} catch (IOException e) {
throw new SystemFailedException(e.getMessage(), e);
}
}
ByteArrayOutputStream bos = null;
InputStream gzip_is = null;
byte[] bytes = null;
try{
bos = new ByteArrayOutputStream();
gzip_is = new GZIPInputStream(in);
copy(gzip_is,bos);
bytes = bos.toByteArray();
}catch(IOException e){
throw new SystemFailedException(e.getMessage(), e);
}finally{
try{
if(gzip_is != null) gzip_is.close();
if(bos != null) bos.close();
}catch(IOException e){
//ignore
}
}
return bytes;
}
public static byte[] doUnZip(final byte[] zippedMessage){
validate(zippedMessage, "Fail to unzip - given bytes is null or empty");
ByteArrayInputStream is = null;
try{
is = new ByteArrayInputStream(zippedMessage);
return doUnZip(is);
}finally{
try{
if(is != null) is.close();
}catch(IOException e){
//ignore
}
}
}
public static String doUnZip(File file){
validate(file);
GZIPInputStream gzipInputStream = null;
StringWriter writer = null;
String result = "";
try{
byte[] buffer = new byte[BYTE_BLOCK_LENGTH];
gzipInputStream = new GZIPInputStream(new FileInputStream(file));
writer = new StringWriter();
while((gzipInputStream.read(buffer)) > 0){
writer.write(new String(buffer));
writer.flush();
}
result = writer.toString();
}catch(IOException e){
//do something to handle exception
}
finally{
try{
if(writer != null){writer.close();}
if(gzipInputStream != null){gzipInputStream.close();}
}catch(IOException e){
//ignore
}
}
return result;
}
private static void validate(File file) {
if(file==null || !file.exists()){
throw new SystemFailedException("Fail to unzip - file is not exist");
}
}
private static void copy(InputStream in, OutputStream out)throws IOException {
byte[] buf = new byte[BYTE_BLOCK_LENGTH];
int len = -1;
while ((len = in.read(buf, 0, buf.length)) != -1) {
out.write(buf, 0, len);
}
}
public static boolean isGzipped(byte[] input){
return isGzippped(new ByteArrayInputStream(input));
}
public static boolean isGzippped(InputStream in){
boolean markSupported = in.markSupported();
boolean result = false;
try {
if(markSupported){
in.mark(0);
result = (readUShort(in) == GZIPInputStream.GZIP_MAGIC);
in.reset();
}
} catch (Exception e) {
result = false;
}
return result;
}
private static int readUShort(InputStream in) throws IOException {
int b = readUByte(in);
return ((int)readUByte(in) << 8) | b;
}
/*
* Reads unsigned byte.
*/
private static int readUByte(InputStream in) throws IOException {
int b = in.read();
if (b == -1) {
throw new EOFException();
}
if (b < -1 || b > 255) {
b = 0;
}
return b;
}
}
答案 3 :(得分：0)
你需要使用由支持抓地力的方形制作的Okhttp。不知道您是否创建了自定义实例，或者默认情况下是否启用了该实例，您应该检查文档。