ProtocolException：意外状态行:HTTP/1.1 422无法处理的实体

Question

我正在使用Retrofit+Okhttp发出POST请求，遇到以下错误：

02-05 04:45:13.981  15972-16249/com.myapp.android D/Retrofit﹕ ---> HTTP POST http://10.0.0.4:3000/api/v1/users/1/posts
02-05 04:45:13.981  15972-16249/com.myapp.android D/Retrofit﹕ Accept: application/json
02-05 04:45:13.981  15972-16249/com.myapp.android D/Retrofit﹕ Content-Type: application/json; charset=UTF-8
02-05 04:45:13.981  15972-16249/com.myapp.android D/Retrofit﹕ Content-Length: 150
02-05 04:45:13.981  15972-16249/com.myapp.android D/Retrofit﹕ {"description":"test","image_url":"https://s3.amazonaws.com/bucket/xxx-4800-b0e0-fc206f95f158.jpeg","title":"test","price":0.0,"user_id":0}
02-05 04:45:13.981  15972-16249/com.myapp.android D/Retrofit﹕ ---> END HTTP (150-byte body)
02-05 04:45:14.001  15972-15972/com.myapp.android W/EGL_genymotion﹕ eglSurfaceAttrib not implemented
02-05 04:45:14.017  15972-16249/com.myapp.android D/Retrofit﹕ ---- ERROR http://10.0.0.4:3000/api/v1/users/1/posts
02-05 04:45:14.017  15972-16249/com.myapp.android D/Retrofit﹕ java.net.ProtocolException: Unexpected status line: HTTP/1.1 422��Unprocessable Entity
            at com.squareup.okhttp.internal.http.StatusLine.parse(StatusLine.java:73)
            at com.squareup.okhttp.internal.http.HttpConnection.readResponse(HttpConnection.java:187)
            at com.squareup.okhttp.internal.http.HttpTransport.readResponseHeaders(HttpTransport.java:80)
            at com.squareup.okhttp.internal.http.HttpEngine.readNetworkResponse(HttpEngine.java:791)
            at com.squareup.okhttp.internal.http.HttpEngine.access$200(HttpEngine.java:90)
            at com.squareup.okhttp.internal.http.HttpEngine$NetworkInterceptorChain.proceed(HttpEngine.java:784)
            at com.squareup.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:645)
            at com.squareup.okhttp.Call.getResponse(Call.java:263)
            at com.squareup.okhttp.Call$ApplicationInterceptorChain.proceed(Call.java:219)
            at com.squareup.okhttp.Call.getResponseWithInterceptorChain(Call.java:192)
            at com.squareup.okhttp.Call.execute(Call.java:79)
            at retrofit.client.OkClient.execute(OkClient.java:53)
            at retrofit.RestAdapter$RestHandler.invokeRequest(RestAdapter.java:326)
            at retrofit.RestAdapter$RestHandler.access$100(RestAdapter.java:220)
            at retrofit.RestAdapter$RestHandler$1.invoke(RestAdapter.java:265)
            at retrofit.RxSupport$2.run(RxSupport.java:55)
            at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at retrofit.Platform$Android$2$1.run(Platform.java:142)
            at java.lang.Thread.run(Thread.java:841)
02-05 04:45:14.017  15972-16249/com.myapp.android D/Retrofit﹕ ---- END ERROR

使用以下库：

compile 'com.squareup.retrofit:retrofit:1.9.0'
compile 'com.squareup.okhttp:okhttp-urlconnection:2.2.0'
compile 'com.squareup.okhttp:okhttp:2.2.0'

我期待着类似以下内容的出现（有意测试一个422错误）：

{
    "title": [
        "is too short (minimum is 6 characters)"
    ]
}

render json: @post.errors.to_json, status: :unprocessable_entity

这是合适的十六进制。

Answer 1

您的服务器似乎违反了HTTP规范。状态行定义如下：

响应消息的第一行是状态行，包括协议版本、空格(SP)、状态码、另一空格、描述状态码的可能为空的文本短语，并以CRLF结尾。

status-line = HTTP-version SP status-code SP reason-phrase CRLF

从异常来看，状态代码和原因短语之间似乎有一个（或两个）非空格字符。