Forum Discussion
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
Hi Anonymous
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 Outputregards
Phil
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2 Replies
Hi Anonymous
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 Outputregards
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.