wasm: don't send request body as plain uint8 array

[nwolber]

#1354 claims to fix the issue that bodies are sent as plain uint8 array. But, for me, this is unfortunately still the case.

This MR would add:

• A fix for the issue
• An improved test case that generates a request and checks the body contains what it should.

[seanmonstar]

Sigh, why is github auto merge merging things that don't pass CI?

[crapStone]

@nwolber you just reverted this (#1341) PR. Are you sure it doesn't break anything again?

[nwolber]

@crapStone Yes, you are right. Thank you for pointing that out. To get hold of the issue around body formatting I created new test cases for all basic types supported by Body as well as a test case for multipart in my fork here:

• basic: https://github.com/nwolber/reqwest/blob/non-multipart-vs-multipart/src/wasm/body.rs#L166
• multipart: https://github.com/nwolber/reqwest/blob/non-multipart-vs-multipart/src/wasm/multipart.rs#L287

I assembled the three variants of the particular code in Body.to_js_value that existed over time

let body_bytes: &[u8] = body_bytes.as_ref();
let body_uint8_array: Uint8Array = body_bytes.into();

// 1 current code on master
let js_value: &JsValue = body_uint8_array.as_ref();

// 2 code after #1354
let body_array = js_sys::Array::from(&body_uint8_array);
let js_value: &JsValue = body_array.as_ref();

// 3 code after 1341
let body_array = js_sys::Array::new();
body_array.push(&body_uint8_array);
let js_value: &JsValue = body_array.as_ref();

Ok(js_value.to_owned())

It turns out with the current code we can't have both working.

On Firefox 93.0 the results for me are the following:

Number	Basic	Multipart
1	✔️	❌
2	❌	❌
3	❌	✔️

I ran the tests on Rust stable (i.e 1.55.0) with wasm-pack test --firefox --features multipart on wasm-pack 0.10.1.

At the moment I don't see a solution how basic cases and the multipart case can share the same code in Body.to_js_value

edited for clarity

[crapStone]

So my code didn't work at all 😅

Why does the multipart body take this code at all? It shouldn't even be supported unless you activate the multipart feature and then it should use the code of the other match-arm.