Support some playground features by using play.golang.org

[cmars]

There might be a a way to run Go code examples from a statically hosted 'represent' slide in the main public Go playground. Create a URL with a POST, then display in an iframe?

<Tv> ohh at least godoc.org just redirects you to play.golang.org
<Tv> cmars: sounds likely <Tv> http://godoc.org/encoding/json#example-Decoder <- click play
Tv: interesting... i wonder how that play link was created? automatically by godoc i assume <Tv> http://golang.org/pkg/encoding/json/#example_Decoder POSTs to http://golang.org/compile
<Tv> curl http://golang.org/compile --data-urlencode body='package main' <Tv> {"compile_errors":"runtime.main: undefined: main.main\n [process exited with non-zero status]\n","output":""}
ah :)
<Tv> -d version=2 also if you want to emulate it more <Tv> maybe the redirect was just to avoid rewriting the form editing ui
I recommend looking at talks.godoc.org. It runs code in place.`

[tv42]

Relevant: http://godoc.org/code.google.com/p/go.tools/playground

[amitu]

I think its a good idea. A pull request is needed. Anybody thought how to implement this?

[amitu]

Here is what I got so far. First lets assume we are okay being wasteful. In ideal condition we would only create one playground for one file, if content is same, we reuse the playground url, which we dont care about, as first cut.

We will have to modify renderDoc() in dir.go file, iterate over the doc there, iterate over doc.Sections, and then for each element in section.Elements of type Code, and submit the code.Raw to http://golang.org/compile, get a URL, and.. this is where I am stuck. I do not understand go templates yet. We will basically get a list of URLs, and ideally I would just put it on code.PlayGroundURL lets say, but I cant modify existing structs. So I suppose I can create my own struct, and replace the section.Elements() with our own struct, which as long as it implements Elem interface, its good.

Then I will have to modify the action.templ, and probably the css file. Sounds good?

[tv42]

Perhaps you can POST from javascript at the time a user clicks a Run button, to avoid that waste? Not sure about cross-domain implications.

[amitu]

@tv42, that would be way worse :-p

Imagine a slide got accessed by thousands of people, will create thousands of playground urls. I just feel wrong about it. We should/can not do this on page load or on button click, it has to be already present, should be done on compile time.

[tv42]

The playground is deterministic. The same source gets the same share url. The compilation and execution are also deterministic, and cached; when you write a for loop with a sleep inside it, the slow output you see is completely simulated by your browser.

[amitu]

Cross site post from browsers without CORS support on their side is not possible :-(

I sent them a mail, they are cool if we do compilation/link generation on "compile" time and put the links in the html. For now this will have to do.

Unless someone mails a CORS enabled gae hosted service that all represent slides can use. Anybody up for it? Should be a fun project.

[amitu]

I sent them a mail and they are cool as long as we make sure "represent" is used as user-agent in requests going to them.

I have also implemented the CORS thing: play.amitu.com.

Working on a pull request.