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gaccardo-slb
Advocate II
Advocate II

How to avoid HTTP 502/503 when accessing a REST API

We are reading data from a REST API.  The process is fairly common: do one call to get a list of IDs, then do one or more calls for each ID to get the details.  For a small data set, everything works fine.  With a large number of IDs, the number of REST calls arriving at the server simulateously is extremely high.  This causes the server to return 502/503 errors and the data loading fails.

 

With other languages, a typical solution is to either make the calls sequentially instead of in parallel, or to rate-limit the calls in some way.  The reduces the onslaught of requests to the server and allows the server to answer the requests instead of rejecting them.  Is there a way to accomplish this with Power Query?

 

Regards,

G

1 ACCEPTED SOLUTION
PhilipTreacy
Super User
Super User

Hi @gaccardo-slb 

You can use Function.InvokeAfter to introduce a delay between requests.  This code has a 2 second delay between web requests

 

let
    id_list = {1 .. 5},
    GetWeb = (id) => Json.Document(Web.Contents("https://jsonplaceholder.typicode.com/todos/" & Text.From(id))),
    Output = List.Transform(id_list, each Function.InvokeAfter( ()=>GetWeb(_), #duration(0,0,0,2)))    
in
    Output

 

regards

Phil


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View solution in original post

2 REPLIES 2
PhilipTreacy
Super User
Super User

Hi @gaccardo-slb 

You can use Function.InvokeAfter to introduce a delay between requests.  This code has a 2 second delay between web requests

 

let
    id_list = {1 .. 5},
    GetWeb = (id) => Json.Document(Web.Contents("https://jsonplaceholder.typicode.com/todos/" & Text.From(id))),
    Output = List.Transform(id_list, each Function.InvokeAfter( ()=>GetWeb(_), #duration(0,0,0,2)))    
in
    Output

 

regards

Phil


If I answered your question please mark my post as the solution.
If my answer helped solve your problem, give it a kudos by clicking on the Thumbs Up.



Did I answer your question? Then please mark my post as the solution.
If I helped you, click on the Thumbs Up to give Kudos.


Blog :: YouTube Channel :: Connect on Linkedin


Proud to be a Super User!


Beautiful!

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