I am using the retrofit 2 and OkHttp3 to request data from server. I just added a offline cache code but It's not working as expected. I got the error "Unable to resolve host "<>": No address associated with hostname."
This occurs when It's try to get the retrieve data from the cache(when no internet connection). A code snippet is below.
public static Interceptor provideCacheInterceptor() {
return new Interceptor() {
@Override
public Response intercept(Chain chain) throws IOException {
Response response = chain.proceed(chain.request());
// re-write response header to force use of cache
CacheControl cacheControl = new CacheControl.Builder()
.maxAge(2, TimeUnit.MINUTES)
.build();
return response.newBuilder()
.header(CACHE_CONTROL, cacheControl.toString())
.build();
}
};
}
public static Interceptor provideOfflineCacheInterceptor() {
return new Interceptor() {
@Override
public Response intercept(Chain chain) throws IOException {
Request request = chain.request();
if (!hasNetwork) {
CacheControl cacheControl = new CacheControl.Builder()
.onlyIfCached()
.maxStale(7, TimeUnit.DAYS)
.build();
request = request.newBuilder()
.removeHeader("Pragma")
.cacheControl(cacheControl)
.build();
}
return chain.proceed(request);
}
};
}
private static Cache provideCache() {
Cache cache = null;
try {
cache = new Cache(new File(AdeptAndroid.getInstance().getCacheDir(), "http-cache"),
10 * 1024 * 1024); // 10 MB
} catch (Exception e) {
Log.d("Test", "Could not create Cache!");
}
return cache;
}
And finally a method which combine all of these is here.
private static OkHttpClient provideOkHttpClient() {
return new OkHttpClient.Builder()
.addInterceptor(provideHttpLoggingInterceptor())
.addInterceptor(provideOfflineCacheInterceptor())
.addNetworkInterceptor(provideCacheInterceptor())
.cache(provideCache())
.build();
}
I had the same error in my project with kotlin, and I fixed it like this:
client.addInterceptor(provideOfflineCacheInterceptor(context))
client.addNetworkInterceptor(provideCacheInterceptor(context))
private fun provideOfflineCacheInterceptor(context: Context): Interceptor {
return Interceptor { chain ->
var request = chain.request()
var cacheHeaderValue = if (!hasNetwork(context)!!){
"public, only-if-cached, max-stale=" + 60 * 60 * 24 * 1
} else {
"public, max-age=" + 5
}
request = request.newBuilder().header("Cache-Control", cacheHeaderValue).build()
chain.proceed(request)
}
}
private fun provideCacheInterceptor(context: Context): Interceptor {
return Interceptor { chain ->
val request = chain.request()
var cacheHeaderValue = if (!hasNetwork(context)!!){
"public, only-if-cached, max-stale=" + 60 * 60 * 24 * 1
} else {
"public, max-age=" + 5
}
//request = request.newBuilder().build()
val response = chain.proceed(request)
response.newBuilder()
.removeHeader("Pragma")
.removeHeader("Cache-Control")
.header("Cache-Control", cacheHeaderValue)
.build()
}
}