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Anonymous's avatar
Anonymous
Not applicable
7 years ago
Solved

Delay web query until condition met from another web query

I use an API that provides a Json response which includes a statusUrl and a downloadUrl. If I immediately hit up the downloadUrl there is usually no data. The statusUrl Json response advises when t...
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  • Nolock's avatar
    Nolock
    7 years ago

    Hi Anonymous,

    I've prepared a template which you can use for solving your problem.

    You have to add your logic for processing JSON responses and modify the WaitForList according your needs.

    let
    // request data
    RequestDataRecord = fnProcessJson(Web.Contents("request data URL")),

    // wait 10x for 5 seconds
    WaitForList = List.Repeat({5}, 10),
        // wait until the response is COMPLETE, but max 50 secs
    WaitForStatus = List.MatchesAny(
            WaitForList,
            each 
                Function.InvokeAfter(
                    () => fnProcessJson(Web.Contents("http://StatusCheckURL")), 
                    #duration(0,0,0,_)
                ) = "COMPLETE"
            ),
    
    // download file if WaitForStatus was successful        
    DownloadFile =
        if WaitForStatus then
            fnProcessJson(Web.Contents("download data URL"))
        else
            null
in
    DownloadFile
Anonymous's avatar
Anonymous
Not applicable
7 years ago

Thanks, Nolock 
Looks like this will do the job, just working through it at the moment.


What should the output of the function in the middle be? Should it be text? a list?

I think that's where I'm failing now..

 

Nolock's avatar
Nolock
Resident Rockstar
7 years ago

Hi Anonymous,

do you mean this function? 

() => fnProcessJson(Web.Contents("http://StatusCheckURL"))

The result should be the status (i.e. COMPLETE, INPROGRESS, FAILED, ...) and its datatype is text because I compare it with the string "COMPLETE" on the next line.

But you can modify the code in a form which fulfils all your expectations. It is just a template how it could work.

  • Anonymous's avatar
    Anonymous
    Not applicable
    7 years ago
    Yep, that's the function. So.. I created the function, the output is text "COMPLETE" .
    I'm not sure what odds going wrong, I still get the "null" output.
    • Nolock's avatar
      Nolock
      Resident Rockstar
      7 years ago

      Hi Anonymous,

      a simplified version that waits just for one second and then returns "xxx". Maybe it helps.

      let
    // wait 10x for 5 seconds
    WaitForList = List.Repeat({1}, 10),
    WaitForStatus = List.MatchesAny(
            WaitForList,
            each 
                Function.InvokeAfter(
                    () => "COMPLETE", 
                    #duration(0,0,0,_)
                ) = "COMPLETE"
            ),
            
    DownloadFile =
        if WaitForStatus then
            "xxx"
        else
            null
in
    DownloadFile