in reply to Re^5: webperl: fetching data over the web
in thread webperl: fetching data over the web

Thank you, with that HTML file I can reproduce it too. (BTW, req.open('GET', 'http://localhost:5000/emperl.js', false); should probably be req.open('GET', url, false);)

emperl.js is pretty huge, so I tried changing it to webperl.js, and although it exhibited the same behavior of seeming to block the webpage, after a little while it got unstuck and displayed the output. If you do print length(js(...)) instead of print js(), you get a result much quicker. The same is true if you remove the <textarea> from the HTML page, which causes the output to go to the JS console. There is obviously something very inefficient going on with the <textarea>, I'll take a guess that it's this line: ta.value = ta.value + str;.

I didn't put a lot of effort into optimizing the STDOUT/ERR routines because in the WebPerl applications I was imagining, there wouldn't be any console output, and everything would get handled through the UI. But in the case of this textarea, there's certainly a lot of room for improvement. (Patches welcome :-) )

The endless loop of initializing/ended is also interesting, something I haven't seen yet, could you tell me the steps to reproduce that?

Replies are listed 'Best First'.
Re^7: webperl: fetching data over the web
by LanX (Saint) on Nov 08, 2018 at 18:14 UTC
    running in Edge gives more hints

    weblib_demo.html ...

    prints this output into the textarea 

    wasm streaming compile failed: CompileError: Function body too big
falling back to ArrayBuffer instantiation
failed to asynchronously prepare wasm: CompileError: Function body too
+ big
CompileError: Function body too big
CompileError: Function body too big

    [download]

    plus a popup "Perl Aborted"

    democode/demo.html ...

    does 2-4 popups saying "Perl aborted"

    I also have the feeling that a reload doesn't do a reset of the Perl engine.

    > should probably be req.open('GET', url, false);

    Indeed, fixed :)

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

[reply]
[d/l]

      Unfortunately I'm not all too surprised IE/Edge has some issues :-/ Unless I have confirmation otherwise, I'm going to assume it's a bug in the browser ;-)

[reply]
[d/l]
[select]
Re^7: webperl: fetching data over the web
by LanX (Saint) on Nov 08, 2018 at 18:21 UTC
    > The endless loop of initializing/ended is also interesting, something I haven't seen yet, could you tell me the steps to reproduce that? NB demo.html not index.html like in the online version.

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

[reply]

      Thank you! The error I get on the JS console is: Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:5000/emperl.wasm. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). I addressed that issue in 4a7dd5709b, which is unfortunately not part of v0.07-beta.

      For development, I would suggest this instead:

      $ git clone https://github.com/haukex/webperl.git
$ wget https://github.com/haukex/webperl/releases/download/v0.07-beta/
+webperl_prebuilt_v0.07-beta.zip
$ unzip webperl_prebuilt_v0.07-beta.zip
$ cp webperl_prebuilt_v0.07-beta/emperl.* webperl/web/
$ cd webperl
$ plackup web/webperl.psgi

      [download]

      Then browse to http://localhost:5000/democode/demo.html.

[reply]
[d/l]
[select]
Re^7: webperl: fetching data over the web
by LanX (Saint) on Nov 10, 2018 at 16:54 UTC
    > There is obviously something very inefficient going on with the <textarea>, I'll take a guess that it's this line: ta.value = ta.value + str;.

    I've testet it in pure JS inside your webperl/plack environment.

    Adding the whole of emperl.js to a textarea works without problem in my FF.

    But appending 3000 lines in a loop creates an "out of memory" exception (adding only half the lines still works)

    So buffering output (think $| ) might be a solution.

    I'm expecting your ta.scrollTop = ta.scrollHeight; to mean even more trouble. *

    Read more... (1406 Bytes)

    Cheers Rolf
    (addicted to the Perl Programming Language :)
    Wikisyntax for the Monastery FootballPerl is like chess, only without the dice

    *) indeed scrolling makes the whole unresponsive with much smaller line-counts already.

[reply]
[d/l]
[select]

      What's even worse is that Emscripten may decide to provide the STDOUT stream on a character-by-character basis! (I don't think there's a clear spec on its behavior, i.e. whether it's characters or blocks.)

[reply]

In Section Seekers of Perl Wisdom