[Xapian-discuss] Node.js binding

[Liam]

On Fri, Oct 14, 2011 at 8:07 AM, Dan Colish <dcolish at gmail.com> wrote:

> On Fri, Oct 14, 2011 at 4:15 AM, Richard Boulton <richard at tartarus.org
> >wrote:
>
> > On 14 October 2011 10:50, Liam <xapian at networkimprov.net> wrote:
> > > Wondering if anyone's considered/planning a Node.js binding? (I can
> > > contribute to the effort; I have modest experience with the V8 api;
> > though
> > > haven't started with xapian yet.)
> >
> > I took a look at making one a while ago (when Node was pretty new) -
> > actually making an extension which calls some Xapian functions from
> > node is pretty easy to do by hand (though wrapping the full API would
> > be harder - and I don't think SWIG has any stable V8/javascript
> > support currently, so it would either have to be done manually or swig
> > would have to be modified.
> >
> > The significant problem though is that many Xapian calls are
> > long-running, so need to be run in a sub-thread or sub-process.  Is
> > there any built-in support for that sort of thing in Node now? (there
> > wasn't when I last looked).
> >
> > Alternatively, you could just make a client in V8 for a search server
> > built around Xapian (eg; http://restpose.org).
>
>
> I also looked into this a few months ago and I think a naive implementation
> would be easy. The issue I have is how to avoid blocking the main event
> loop
> in Node.js. Now that I've thought about it a bit more, I think using
> futures
> or promises to avoid blocking would be an alternative to just forking and
> polling. Otherwise, I think that an API client to Restpose is a reasonable
> solution
>

Preventing a library call from blocking Node is easy; there's a thread pool
to which you queue with a single call. There's sample code in the project I
linked. Typically you'd reduce trips through the thread pool during result
iteration via a method like get_n(max, result_callback, done_callback),
which is a little more involved.

V8 doesn't support SWIG, but wrapping the entire api might not be necessary
to get started. Extending a working module is simple.

A client for Restpose, assuming it's socket-based, could be done in Node
Javascript. That would be a decent way for me to prototype, absent a
binding...