B4J Question Working with jOkHTTPUtils2 - How to synchronous calls

[Giu]

Hi all,

I started a little console application I wanna do with B4J.
App is simple, I have to connect to a postgres database (done) retrieve data from a table, iterate over it, and for each record I have to do a web request to retrieve a JSON to parse and take several URLs, then I have to download this images/files with that URL and fill a CSV. It's an easy task, and I started playing with pgsql connection (done) a simple select to try (done) and now I'm working with the communication with the API. I connect and retrieve data (the access_token for start) following jOkHttpUtils2 post samples. And it works, but I noticed getToken request is async, and I need to be synchronous because I can't continue with operations until I get this validation.

This is my code:

..
..
    'ConnectToDatabase
    GetToken
    StartMessageLoop 'only required in a console app
End Sub

Sub GetToken() 'As String
    Dim j As HttpJob
    j.Initialize("", Me)
    j.PostString(baseURLToken, baseBodyToken)
    Wait For (j) JobDone(j As HttpJob) ' -- para peticiones asyncronas
    If j.Success Then
        Dim jp As JSONParser
        jp.Initialize(j.GetString)
        Dim response As Map = jp.NextObject
        token = response.Get("access_token")
        'Return response.Get("access_token")
    Else
        Log(j.Response.ErrorResponse)
    End If
    j.Release 
End Sub

As far as I undersand this code is async because the Wait, but "Wait" resumes the execution of my app, and I need to really wait until I get the token to continue processing other things.
I tried to remove Wait command and move the code after it, to a Sub called "JobDone(j as HttpJob)" and this worked, but this way all jobs done will end there and I have to control there the name of the job and so on to do one or other things, and I don't see it too much elegant. I tried calling it GetToken_JobDone as I remember to see this kind of nomenclature some years ago, and IDE don't warning about sub not being called, but debuging, is never called.

What I'm doing wrong?

 

[EnriqueGonzalez]

getToken request is async,

You have to wait for getToken now.

private sub app_start...

tokenizer ' you need to create this extra sub becasue appstart cant be a resumable sub
StartResumableSub
end sub

private sub tokenizer
 dim xrs as resumableSub = getToken
 Wait for (xrs) complete (success as boolean)
 if not(sucess) then return

 ' do more stuff after token passed

end sub

sub getToken as ResumableSub

...
return true
end sub

 

[Giu]

Sorry I think I don't understand. This is keeping the wait inside GetToken? Or removing it?
Removing the wait inside GetToken I got it working creating a sub called JobDone but I don't like to have to check wich job called this sub.

 

[EnriqueGonzalez]

Keeping it

 

[Giu]

I advanced on my project, and I'm so so confused. There is no way to just work as traditional way, where I call a sub/process or whathever, and just process line by line? Now I don't have clear where is my starting point. I created a StartProcess point I call before StartMessageLoop

Sub AppStart (Args() As String)
    If Args.Length <> 1 Or (Args(0) <> "--prod" And Args(0) <> "--test") Then
        Utils.PrintCommandLineArguments
        ExitApplication
    Else
        ' SET SOME VARS
    End If

    StartProcess
    StartMessageLoop
End Sub

Sub StartProcess()
    Database.ConnectToDatabase
    OCApi.CreateToken
    Dim itemsRS As ResultSet = Database.GetItems ' <-------------------- here token is empty
    Do While itemsRS.NextRow
        OCApi.GetItemInfo(itemsRS.GetString2(0), 0)
      
    Loop
End Sub

' ********************************************* OCApi MODULE **********************************************

Sub CreateToken()
    Dim getTokenSub As ResumableSub = GetToken
    Wait for (getTokenSub) complete (getTokenComplete As Boolean)
    If getTokenComplete = False Then
        ExitApplication             
    End If

End Sub

Sub GetToken() As ResumableSub
    Dim j As HttpJob
    j.Initialize("GetToken", Me)
    j.PostString(baseURLToken, baseBodyToken)
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Dim jp As JSONParser
        jp.Initialize(j.GetString)
        Dim response As Map = jp.NextObject
        token = response.Get("access_token")
        Return True
    Else
        Log("Error trying to get token.")
        Log(j.Response.ErrorResponse)
    End If
    j.Release
    Return False
End Sub

Sub GetItemInfo(item As String, intento As Int)As ResumableSub
    Dim j As HttpJob
    j.Initialize("GetItemInfo", Me)
    j.GetRequest.SetHeader("Authorization", "Bearer " & token)
    j.GetRequest.SetContentType("application/json")
    j.PostString(baseURLProduct & item, Null)
  
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Dim jp As JSONParser
        jp.Initialize(j.GetString)
        Dim response As Map = jp.NextObject
        token = response.Get("access_token")
        Return True
    Else
        If j.Response.StatusCode = 401 Then
            If (intento < 3) Then
                intento = intento + 1
                CreateToken
                GetItemInfo(item, intento)
            End If
        End If
      
        Log("Error trying to get item info.")
        Log(j.Response.ErrorResponse)
    End If
    j.Release
    Return False
End Sub

Well, When I suppose to get the item info, I should have the token there, and is empty

 

[EnriqueGonzalez]

OCApi.CreateToken

In startprocess:

Dim xrs as resumablesub = ocapi.gettoken
Wait for (xrs) complete (success as boolean)

I don't think you need the createtoken sub