HTTP FAILED: java.net.SocketException: Socket closed; doesn't fire up exception handling methods

Question

I have an RxJava chain request that should release some locks onError(), or onComplete(), so, basically, what my problem is: when I set read, connect and write timeouts to my OkHttpClient, I don't get the desired behavior. I'm using Retrofit2 and OkHttp3.6.0 Here's my simplified client:

OkHttpClient.Builder builder = new OkHttpClient.Builder()
           .readTimeout(30, TimeUnit.SECONDS)
           .connectTimeout(30, TimeUnit.SECONDS)
           .writeTimeout(30, TimeUnit.SECONDS)
OkHttpClient okHttpClient = builder.build();

Here's a simplified version of the chain request I have:

public <T extends Response> Observable<T> doSomething(Observable<T> base) {
    isLocked = true;
    return someApiCall()
               .flatMap(apiResponse -> handleResponse(apiResponse, base)
                   .doOnError(throwable -> {
                       isLocked = false;
                   })
                   .doOnCompleted(() -> {
                       isLocked = false;
                   }));
}

handleResponse() makes another API call and returns an Observable<Response<Something>> but, as I've said, it sometimes fails with a HTTP FAILED: java.net.SocketException: Socket closed and it never finishes the Observable, so, onError() or onComplete() are never called. I've tried onTerminate() also, but with no luck. When I remove the timeout settings from the OkHttlClient, the SocketException is actually thrown and caught which releases the isLocked variable. I've tried wrapping the handleResponse() return statement with a try {} catch (Exception e) {} block, but even that doesn't catch the SocketException when the custom timeouts are set. Any ideas?

Answer 1

In Retrofit 2, exceptions below/above the HTTP layer are not reported as Response<?>, but as actual exceptions via onError.

In your case, you should move the doOnError/doOnCompleted out of the flatMap; as it is right now they respond to errors generated in the handleResponse only - but that method won't be called if someApiCall returns an error Observable.

Answer 2

It turns out that the request was getting unsubscribed, which caused the appearance of the HTTP FAILED: java.net.SocketException: Socket closed error, so, the solution was just adding this code to the chain:

.doOnUnsubscribe(() -> {
    isLocked = false;
})

I still don't understand why the custom timeout value was triggering the SocketException, but I suppose that the socket was waiting for the timeout to expire and close, or complete the request and close, but it got interrupted by the unsubscribe call and thus closed unexpectedly.

Answer 3

I solved this situation in Android with the option retryOnConnectionFailure(true) set with the builder.

Given that Retrofit 2 just receive the OkHttpClient object.