Break up Angular http post into multiple calls

Question

Our service times out if we post too many items at the same time, what I am looking for is the RxJs operator that will allow me to serialise the post into multiple posts, something like

merge(
  chunk(items, 50).map(
    chunkItems => this.http.post('endPoint', chunkItems)
  )
).pipe(
  scan((errors, current) => [...errors, ...current], []);
)

But I don't want them to run in parallel like merge will, I want it to be like a switchMap that serialises the calls.

chunk is a function that breaks an array up into smaller chunks

export const chunk = (arr, len) => {
  let chunks = [],
    i = 0,
    n = arr && arr.length;

  while (i < n) {
    chunks.push(arr.slice(i, (i += len)));
  }

  return chunks;
};

have you tried this answer - https://stackoverflow.com/questions/57784571/angular-7-handling-large-post-http-request — Ismail, Nov 28 '19 at 05:03

score 1 · Accepted Answer · answered Nov 28 '19 at 05:19

1

Suppose you have dataList type of array with agreement count of 3, Try this.

dataList=[data1,data2,data3]
const agreement =3
from(dataList).pipe(mergeMap(request=>this.http
    .post(this.url + this.saveRequestUrl, request, this.options),null,agreement )

answered Nov 28 '19 at 05:19

Ashutosh Kushawaha

751
8
16

Cheers, using from is the part I wasn't getting right – Adrian Brand Nov 28 '19 at 06:02

score 0 · Answer 2 · answered Nov 28 '19 at 06:04

0

What I have done is

from(chunk(items, 50)).pipe(
  concatMap(chunkItems => this.http.post('endPoint', chunkItems)),
  scan((errors, current) => [...errors, ...current], [])
);

answered Nov 28 '19 at 06:04

Adrian Brand

20,384
4
39
60

Break up Angular http post into multiple calls

2 Answers2