Re: Service Worker does not allow XMLHttpRequest

[Lucas Pardue]

Hi Alon,

Thanks for the feedback. 

I'm not sure legacy vm support is.

Looking at the code, it seems that XHR is used in the browser environment 
(ENVIRONMENT_IS_WEB, ENVIRONMENT_IS_WORKER), so replacing XHR with Fetch is 
possible and preferred. Feature detection could be used to detect Fetch and 
fallback.

I don't know if we have the resource to make a PR. I've created issue #6241 
 to track the problem. A 
PR (whomever writes it) can reference that issue.

Kind regards
Lucas

On Monday, February 12, 2018 at 9:20:08 PM UTC, Alon Zakai wrote:
>
> Interesting, I didn't know Service Workers disallowed XHRs but allow 
> fetch. Then yes, we should use fetch where it is available.
>
> The place to fix this is in src/shell.js, in readAsync. Apparently fetch 
> is in all modern browsers now, https://caniuse.com/#search=fetch so we 
> can probably just use fetch (or maybe fall back to XHR if legacy vm support 
> is enabled).
>
> Feel free to open a PR with that, or if not then please open a github 
> issue for this and hopefully someone else will soon.
>
> On Fri, Feb 9, 2018 at 10:00 AM, Lucas Pardue  > wrote:
>
>> Hi,
>>
>> We have a little project that we've run through emscripten and it 
>> produces an asm.js output called example.js, and example.js.mem. Inside 
>> example.js is the generated function fetchRemotePackage(), which uses 
>> XMLHttpRequest (XHR is also used elsewhere in example.js).
>>
>> I've tried to use this in my Service Worker, starting simply with 
>> importScripts('example.js'). Unforturnately both Chrome and Firefox return 
>> a ReferenceError stating that XMLHttpRequest is not defined. It seems that 
>> Service Worker does not support XHR and it would rather I use the WHATWG 
>> Fetch 
>> API . Note that this is seems to be 
>> completely distinct from Emscripten's Fetch API.
>>
>> I wondered if this issue with Service Worker was already on Emscripten's 
>> radar, a search did not yield much. I also had a look if there was some 
>> kind of build option that would replace XHR with Fetch but did not have 
>> much luck.
>>
>> I suppose I could manually transform the generated code with 
>> --js-transform but that does not seem ideal, especially since the problem 
>> is so broad as to affect all Service Workers.
>>
>> Any tips?
>>
>> Kind regards
>> Lucas
>>
>>
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>
>

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Re: Service Worker does not allow XMLHttpRequest

[Alon Zakai]

Interesting, I didn't know Service Workers disallowed XHRs but allow fetch.
Then yes, we should use fetch where it is available.

The place to fix this is in src/shell.js, in readAsync. Apparently fetch is
in all modern browsers now, https://caniuse.com/#search=fetch so we can
probably just use fetch (or maybe fall back to XHR if legacy vm support is
enabled).

Feel free to open a PR with that, or if not then please open a github issue
for this and hopefully someone else will soon.

On Fri, Feb 9, 2018 at 10:00 AM, Lucas Pardue 
wrote:

> Hi,
>
> We have a little project that we've run through emscripten and it produces
> an asm.js output called example.js, and example.js.mem. Inside example.js
> is the generated function fetchRemotePackage(), which uses XMLHttpRequest
> (XHR is also used elsewhere in example.js).
>
> I've tried to use this in my Service Worker, starting simply with
> importScripts('example.js'). Unforturnately both Chrome and Firefox return
> a ReferenceError stating that XMLHttpRequest is not defined. It seems that
> Service Worker does not support XHR and it would rather I use the WHATWG Fetch
> API . Note that this is seems to be
> completely distinct from Emscripten's Fetch API.
>
> I wondered if this issue with Service Worker was already on Emscripten's
> radar, a search did not yield much. I also had a look if there was some
> kind of build option that would replace XHR with Fetch but did not have
> much luck.
>
> I suppose I could manually transform the generated code with
> --js-transform but that does not seem ideal, especially since the problem
> is so broad as to affect all Service Workers.
>
> Any tips?
>
> Kind regards
> Lucas
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "emscripten-discuss" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to emscripten-discuss+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>

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