Hi all,
I came across this thread, I have searched if there is some "global"
request timeout that we can set on a RPC calls, not RequestBuilder, but the
one from RemoteService created via GWT.create(service) ?
I coudnt find anything, any idea?
Tnx
On Thursday, April 6, 2023 at 2:16:47 PM UTC+2 Colin Alworth wrote:
> What you're looking for is a way to re-try requests in the case where the
> server is unreachable, which is not something that HTTP or the browser
> gives you automatically. If you had a proxy, but the server itself was
> down, the proxy would likely return a 503 service unavailable status, which
> the client could use to retry until the service was available (which might
> only happen for a certain number of seconds or a certain number of tries).
> It might also be possible for a proxy to wait and retry the upstream server
> until it was available, but I can't think of a proxy right now with that
> feature.
>
> HTTP itself doesn't have a timeout feature at all either. The timeout that
> you're setting on the client side is a simple GWT Timer, if the request
> hasn't finished (either in success or failure), it cancels the upstream
> request and presents the failure you're seeing to the client.
>
> Be a little careful when implementing a retry mechanism, as it is possible
> that the call made it to the server, and the server performed the action,
> but the client lost internet connection while the response was on its way
> to the client - that is, retrying a non-idempotent or expensive action may
> cause problems you weren't expecting. A status code of 0 is usually the
> client's way of saying "I wasn't able to get any reply from the server for
> some reason" - taking that information and trying to do something simple
> and idempotent until a server connection can be reestablished lets you know
> that the server and network are both working again, followed by some "did
> my last action succeed" before trying again (or just let the user dismiss
> the message and try again) will help mitigate this class of issues. A proxy
> sending back a 503 is a safer way to be sure that the network connection is
> good, but only the server is down, so you can retry - but be aware that
> technically there might be a network issue between the proxy and server,
> though this is much less likely.
>
> Good luck,
> Colin
>
> On Thursday, April 6, 2023 at 7:05:53 AM UTC-5 Dmitri wrote:
>
>> Dear Colin
>>
>> Thank you so much for your advice. I'll take a closer look at those areas.
>>
>> Just a little clarification: The server is not running at all. Both
>> exceptions are generated from the client only with different timeout
>> settings when it cannot reach the server.
>> When the server is running - no problems in both cases. The purpose of
>> the code is to make the client wait longer when the server is unreachable
>> due to temporary communication problems.
>>
>> PS there are some typos in the codes I provide which I made when clean-up
>> for posting., Please ignore them.
>> Thank you again
>>
>> Best regards
>> Dmitri
>>
>>
>> On Thu, Apr 6, 2023 at 9:49 PM Colin Alworth <nilo...@gmail.com> wrote:
>>
>>> I believe you're experiencing different timeouts in different cases.
>>> That is, the problem you're facing of a short timeout before you use your
>>> RPC_TIMEOUT_MS is a server-side timeout (or potentially a proxy?), but
>>> after you set a client-side timeout, the client is observing that the
>>> server is taking too long, and terminating the call from its side,
>>> resulting in the RequestTimeoutException.
>>>
>>> To confirm this, try setting the client-side timeout to something like
>>> one minute, 60_000, and see that the error returns to the old message you
>>> were seeing. A timeout set like this does not guarantee that the server
>>> stops processing the request, only that the client stops waiting for it,
>>> and it may not be appropriate for your use case at all.
>>>
>>> With the client-side timeout set to a reasonable amount or entirely
>>> removed, take a closer look at the error message you're getting from the
>>> server, and any server or proxy logs you're getting. If there is a proxy,
>>> see if you can connect directly to the server to rule out the proxy setting
>>> this short timeout. Very likely this is a configuration on the server/proxy
>>> that can be change to suit your requirements.
>>>
>>> On Thursday, April 6, 2023 at 2:26:31 AM UTC-5 Dmitri wrote:
>>>
>>>> Dear gurus,
>>>>
>>>> I'm learning Java and GWT and I'm facing a problem with setting timeout
>>>> for PRC calls. I want to extend the RPC timeout before the client reports
>>>> a
>>>> failure. The code I'm using is attached below.
>>>>
>>>> I'm running a client in firefox and experience the following problem:
>>>>
>>>> I want to achieve a timeout of 20-30 seconds. However I can set the
>>>> timeout (RPC_TIMEOUT_MS) only up to 3200mS. In case the server does not
>>>> respond I receive the exception
>>>> "*com.google.gwt.http.client.RequestTimeoutException:
>>>> A request timeout has expired after 3200 ms*" accurately after defined
>>>> time.
>>>>
>>>> However in case set timeout exceeds the 3300ms of above the exception
>>>> is different "*com.google.gwt.user.client.rpc.StatusCodeException: 0*"
>>>> and is thrown always after 3-4 seconds.
>>>>
>>>> What causes this exception and how can I extend the waiting time?
>>>>
>>>> Thank you,
>>>> Best regards
>>>> Dmitri
>>>>
>>>> The code:
>>>> public class MyClass implements EntryPoint {
>>>>
>>>> private static final int RPC_TIMEOUT_MS = 3300;
>>>>
>>>> private static class TimeoutRequestBuilder extends RpcRequestBuilder {
>>>> @Override
>>>> protected RequestBuilder doCreate(String serviceEntryPoint) {
>>>> RequestBuilder builder = super.doCreate(serviceEntryPoint);
>>>> builder.setTimeoutMillis(RPC_TIMEOUT_MS);
>>>> return builder;
>>>> }
>>>> }
>>>>
>>>> private static final RpcRequestBuilder requestBuilder = new
>>>> TimeoutRequestBuilder();
>>>> private final HubServiceAsync myService =
>>>> GWT.create(HubService.class);
>>>>
>>>> @Override
>>>> public void onModuleLoad() {
>>>> ((ServiceDefTarget)
>>>> hmyService).setRpcRequestBuilder(requestBuilder);
>>>>
>>>> final MainView mainView = new MainView(hubService);
>>>>
>>>> RootPanel rootPanel = RootPanel.get();
>>>> rootPanel.add(mainView);
>>>>
>>>> Window.addResizeHandler(new ResizeHandler() {
>>>> @Override
>>>> public void onResize(ResizeEvent event) {
>>>> mainView.resize();
>>>> }
>>>> });
>>>> }
>>>> }
>>>>
>>>>
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