B4J Question How do I detect a Http_job has timed out when I use Wait For

JackKirk · Sep 9, 2022

I have a Http_job, the bare bones of the relevant code to execute it are:

B4X:

    Private XXX_job As Http_Job

    XXX_job.Initialize("List", Me)
    
    wrk_URI stuff here

    XXX_job.Download(wrk_URI)

    XXX_job.GetRequest.Timeout = 30 * DateTime.TicksPerSecond      'I know this is the default
    
    wrk_Authorization stuff here
 
    XXX_job.GetRequest.SetHeader("Authorization", wrk_Authorization)

    Wait For (XXX_job) JobDone (Job As Http_Job)

Occasionally this hangs on the Wait For - I am assuming it is timing out.

How do I detect this?

Thanks...

Ganiadi · Sep 9, 2022

JackKirk said:
I have a Http_job, the bare bones of the relevant code to execute it are:

B4X:

Private XXX_job As Http_Job XXX_job.GetRequest.Timeout = 30 * DateTime.TicksPerSecond 'I know this is the default Wait For (XXX_job) JobDone (Job As Http_Job)

Occasionally this hangs on the Wait For - I am assuming it is timing out.

How do I detect this?

Thanks...

Hi Jack

I do it using below code

B4X:

Private XXX_job As Http_Job 
    XXX_job.GetRequest.Timeout = 30 * DateTime.TicksPerSecond      'I know this is the default
    Wait For (XXX_job) JobDone (Job As Http_Job)
    If XXX_job.Success Then
       log("SUCCESS")
    Else
       Log("Error: " & XXX_job.ErrorMessage)
    Endif
End Sub

JackKirk · Sep 9, 2022

Ganiadi said:
I do it using below code

Ganiadi, thanks for your interest but you are missing the point.

Execution never gets to the other side of the Wait For.

DonManfred · Sep 9, 2022

JackKirk said:
Execution never gets to the other side of the Wait For.

not with the code you posted above.

You are not sending any request here. Not a Get request and even not a Post or any other request.

JackKirk · Sep 9, 2022

DonManfred said:
not with the code you posted above.

DonManfred, as I said "bare bones" - the real code is some 500 lines with lots of comments and all sorts of checks - I can post an edited version but I don't think it will help with finding what is going on.

This is an occasional problem, I have log traced it to the Wait For never returning.

When I dig into the Http_Job, Http_Utils2_Service modules and the OkHttp library there does not appear to be a way to handle a timeout.

Can you see one?

If a timeout caused some error response from these then presumably the Wait For would fire and I would get a Success = False - but this is not happening.

alwaysbusy · Sep 9, 2022

JackKirk said:
DonManfred, as I said "bare bones" - the real code is some 500 lines with lots of comments and all sorts of checks - I can post an edited version but I don't think it will help with finding what is going on.

Maybe just add the request itself to your code (it should not be runnable code), but at least we could see where the call itself is done. Maybe your are setting the timeout before the call (or maybe not, but it is guessing at this point). It has to be done after e.g. j.Download btw.

JackKirk · Sep 9, 2022

alwaysbusy said:
Maybe just add the request itself to your code

DonManfred said:
not with the code you posted above.

Ok, I have made the "bare bones" more elaborate in post #1

I'm a bit cagey with this because this code is part of the account creation code for my big project - I don't want to leave a trail for some deviant to hack into.

This particular code is doing a regular check to see if certain emails have arrived.

agraham · Sep 9, 2022

Something like this might be made to work but I'm not absolutely sure.

Need help with WaitFor [solved]

I have not had much success using WaitFor At the moment, I want to use it to trap either one of two boolean flags after I send a command via AStream. One flag is set when I received a message via AStream_NewData the other is set in a TimeOutTimer_Tick event if the command times out. So I would...

www.b4x.com

EDIT: Yes, I think it will work.

agraham · Sep 9, 2022

Also look at this

[B4X][B4XLib] WaitForWithTimeout --> TimeoutHandler

I have read many times the request for a "Wait For" with the addition of a timeout. This class is an attempt to implement that functionality. It is a B4X class, in the sense that it can be used with B4A, B4J and B4i; after all it uses only one B4XView which is completely optional and almost...

www.b4x.com

aeric · Sep 9, 2022

JackKirk said:
Http_Job

I don't know whether you are using the code module or what. If we use OkHttputils, it should be HttpJob.

JackKirk · Sep 9, 2022

agraham said:
Something like this might be made to work but I'm not absolutely sure.

agraham, I could be wrong, but I think the example you reference actually adds a timeout capability to Astream_NewData which looks like it doesn't have a native timeout.

In the case I outlined in post #1 we seem to have a function that has a native timeout that does not appear to work - or at least I can't get it to work.

Before I started the thread I toyed with adding a Timer to fire if the Wait For didn't.

I don't like this because I couldn't find a way to cancel the Http_Job that was supposed to have timed out - and I wonder what sort of impact this would have on memory consumption if there are numerous Http_Jobs hanging in space.

Is there a way to cancel Http_Jobs? - Http_Job.Release just deletes a file.

JackKirk · Sep 9, 2022

agraham said:
Also look at this

I think I have similar comments to the previous post and I agree with Erel's comment in the thread you referenced:

"In most cases it is a mistake to create a layer above Sleep or Wait For. It makes things more complicated, it might add subtle bugs and it is unlikely to fit many use cases."

agraham · Sep 9, 2022

JackKirk said:
adds a timeout capability to Astream_NewData which looks like it doesn't have a native timeout.

It does but it should be adaptable to any Wait For, with or without a native timeout.

JackKirk · Sep 9, 2022

agraham said:
It does but it should be adaptable to any Wait For, with or without a native timeout.

What happens if you used a Timer override on a Http_Job that never completes?

agraham · Sep 9, 2022

The resumable sub class instance that is being waited on sits in memory waiting for an event on the message loop to restarts it. If the event never arrives then that instance object won't be garbage collected and will sit there occupying as small amount of memory and no CPU cycles. I haven't looked very deeply into the actual mechanism to know if theoretically it could be destroyed, Erel would need to comment on that as it would be done in low-level Java anyway.

However It is puzzling that your HttpJob doesn't time out when it should so prompting this discussion in the first place. Have you tried setting the timeout and invoking the download immediately before the wait for?

JackKirk · Sep 10, 2022

agraham said:
However It is puzzling that your HttpJob doesn't time out when it should

I agree entirely - it seems to be a bug? - I am reluctant to report it as such because Erel regularly shoots my "bug reports" down in flames - but it might be the only way to get his attention.

agraham said:
Have you tried setting the timeout and invoking the download immediately before the wait for?

I don't think I can change the order of statements in post #1 - my understanding is that the statement:

XXX_job.GetRequest.SetHeader("Authorization", wrk_Authorization)

is what causes the job to fire - I could be wrong though.

drgottjr · Sep 10, 2022

follow post #4 from https://www.b4x.com/android/forum/threads/okhttp-cancel-download.61239/
you'll have to do a little work to make it fit your scenario.

also, the failure to time out with ok is apparently not unknown.
ok provides 4 time out settings:

Java:

    OkHttpClient client = new OkHttpClient.Builder()
        .connectTimeout(5, TimeUnit.SECONDS)
        .writeTimeout(5, TimeUnit.SECONDS)
        .readTimeout(5, TimeUnit.SECONDS)
        .callTimeout(30, TimeUnit.SECONDS)
        .build();

our okhttp.jar sets 3 of them. i've played around with setting them variously. anyway, the issue - when it occurs - is said to ignore all 4. you can follow the online discussion starting at google. at my last read, i didn't see a definitive resolution. or even a definitive explanation as to why it occurs at all.

ok also has an automatic retry feature which can be turned off (should that feature be involved). people who have experienced the failure to time out have turned the automatic retry off, the the hanging was not solved...

cancelling the socket connection with a modified okhttputils2 (per post above) and a timer would seem to be a way out.

OliverA · Sep 10, 2022

JackKirk said:
XXX_job.GetRequest.SetHeader("Authorization", wrk_Authorization)

is what causes the job to fire - I could be wrong though.

No. The Wait For is what is causing the HTTP request to process. Please note: all statements between xxx.Download and the Wait For for that particular job must be blocking calls. Otherwise the event queue is processed and the download event occurs and may finish before you set up your Wait For. If that occurs, your Wait For will seem to hang, since the event that it is waiting for has already happened.

TILogistic · Sep 10, 2022

drgottjr said:
follow post #4 from https://www.b4x.com/android/forum/threads/okhttp-cancel-download.61239/
you'll have to do a little work to make it fit your scenario.

also, the failure to time out with ok is apparently not unknown.
ok provides 4 time out settings:

Java:

OkHttpClient client = new OkHttpClient.Builder() .connectTimeout(5, TimeUnit.SECONDS) .writeTimeout(5, TimeUnit.SECONDS) .readTimeout(5, TimeUnit.SECONDS) .callTimeout(30, TimeUnit.SECONDS) .build();

our okhttp.jar sets 3 of them. i've played around with setting them variously. anyway, the issue - when it occurs - is said to ignore all 4. you can follow the online discussion starting at google. at my last read, i didn't see a definitive resolution. or even a definitive explanation as to why it occurs at all.

ok also has an automatic retry feature which can be turned off (should that feature be involved). people who have experienced the failure to time out have turned the automatic retry off, the the hanging was not solved...

cancelling the socket connection with a modified okhttputils2 (per post above) and a timer would seem to be a way out.

How to set the default HTTP connection timeout

Hi, I can set the HTTP connection timeout for a call with Job1.GetRequest.Timeout But I have to do this on every call. Is there a way to set the timeout globally? Thanks

www.b4x.com

TILogistic · Sep 10, 2022

You can add parameters to the builder, see the link

Builder - OkHttp - OkHttp

Square’s meticulous HTTP client for the JVM, Android, and GraalVM

square.github.io

B4X:

Public Sub SetRequestTimeOut(ConnectTime As Long, CallTime As Long, ReadTime As Long)
    Dim jo As JavaObject = HttpUtils2Service.hc
    Dim builder As JavaObject = jo.RunMethod("sharedInit", Array("hc"))
    Dim TimeUnit As JavaObject
    TimeUnit.InitializeStatic("java.util.concurrent.TimeUnit")
    builder.RunMethod("connectTimeout", Array(ConnectTime, TimeUnit.GetField("MILLISECONDS")))
    builder.RunMethod("callTimeout", Array(CallTime, TimeUnit.GetField("MILLISECONDS")))
    builder.RunMethod("readTimeout", Array(ReadTime, TimeUnit.GetField("MILLISECONDS")))
    jo.SetField("client", builder.RunMethod("build", Null))
End Sub

B4J Question How do I detect a Http_job has timed out when I use Wait For

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