Msw: apollo-link-batch-http (batch) queries are not getting intercepted

[antoniosZ]

Environment

| Name | Version |
| ------- | ------- |
| msw | 0.24.2 |
| browser | chrome Version 87.0.4280.88 (Official Build) (x86_64) |
| OS | macOS Big Sur 11.0.1 (20B29) |

Request handlers

export const handlers = [
  graphql.operation((req, res, ctx) => {
    console.log({ req, res, ctx });
    return res(
      ctx.data({
        user: {
          username: 'test',
          firstName: 'John',
        },
      })
    );
  }),

  graphql.query('getTest', (req, res, ctx) => {
    return res(
      ctx.data({
        user: {
          username: 'test',
          firstName: 'John',
        },
      })
    );
  }),
];

Actual request

https://www.apollographql.com/docs/link/links/batch-http/
Using Apollo Client to perform a normal batch query

ie.

import { BatchHttpLink } from "apollo-link-batch-http";
const link = new BatchHttpLink({ uri: "/graphql" });

Current behavior

batch queries are not getting intercepted but if I switch from BatchHttpLink to a regular HttpLink, the interception works as expected.

Expected behavior

batch queries get intercepted

[antoniosZ]

the only way I got graphql batch requests to be intercepted, is by using rest with the full request URL, like so:

rest.post('https://my-graphql-server/endpoint', (req, res, ctx) => {
    ...
}

and then I have to manually analyze the req.body[] and handle/mock the request.
meaning, I lose all the graphql declarative/functionality mswjs provides...

[msutkowski]

@antoniosZ Do you have a repro for this? I haven't tried this feature myself, but I imagine it might have to be linked? https://mswjs.io/docs/api/graphql/link#examples

[antoniosZ]

@msutkowski I tried linking and that didn't help. I'll see if I can quickly create a repro

[antoniosZ]

@msutkowski Unfortunately, I could not find a public graphql server to use for the repro, that supports query batching. please let me know if you have one available and then I can create the demo project that reproduces it... thank you

[msutkowski]

I'm not a graphQL user personally but I can try to take a look at this later and set up a server locally. It's possible that somebody will beat me to this but I'll try to get to it by tomorrow

[msutkowski]

Ah, the issue here is that msw doesn't currently support batch operations. BatchLink is sending over an array of operations, which isn't going to resolve. If you're able to, I'm sure @kettanaito would accept a PR if you have the time to implement this? If not, perhaps someone can jump in :)

[antoniosZ]

@msutkowski this is exactly what is happening. It posts an array, instead of an object...
I wish I could say I have the time to work on it, but I doubt I will be able to get to it.

[msutkowski]

@antoniosZ can you test it out against this preview of the build? https://ci.codesandbox.io/status/mswjs/msw/pr/513/builds/83287 - or npm i https://pkg.csb.dev/mswjs/msw/commit/d19bb4e8/msw and let me know if it works as expected? thanks!

[antoniosZ]

thank you @msutkowski but unfortunately, it does not work.

It appears that the problem is here:
https://github.com/mswjs/msw/pull/513/files#diff-6178a21f02701c9f8fa7ae2cc995b08165615a3afddac155fb850e355269897aR154

[msutkowski]

@antoniosZ Sorry about that, there is a little more work to do here for handling the arrays. I'll get it taken care of today :)

[antoniosZ]

thank you for working on this @msutkowski! Is there a new commit that you would like me to test?