Subj : Synchronet Javascript and reading XML
To   : KenDB3
From : echicken
Date : Wed Jul 27 2016 11:10 pm

> I'm rather stuck on something. Is there a way to read an XML file using the
> Synchronet Javascript model? 

E4X (ECMAScript for XML, IIRC) is still available in Synchronet's JS
interpreter as far as I know.  It's kinda shitty but can get the job done.
Documentation can be found on the web.

There are probably a few Synchronet-specific examples of how to use it;
'exec/load/rss-atom.js', which I made, is not the best but does what it does
and should be easy to follow.  It uses E4X to turn an RSS or Atom feed (both
are XML) into an easier-to-work-with JS object.
 
> JSON has the lovely JSON.parse(), but I'm not sure how to read the data, or
> maybe convert it into JSON to make things easier. I even noticed that
> XMLHttpRequest is not defined, while HTTPRequest is defined. 

XMLHttpRequest is something that exists in browsers, and doesn't necessarily
have to have anything to do with XML.  It's a way for a script to make the
browser load something asynchronously / in the background via HTTP; good for
updating content on a page without the user having to reload.

HTTPRequest is defined if you load 'exec/load/http.js' into your script.
That's an HTTP(S) client for Synchronet's JS environment which you can use in
your scripts (and I assume you already do in that weather script).

> A lot of the code snippets I find tend to use things in the DOM and has
> things like hasChildNodes which is not defined in Core JS or Sync. 

Yes, if you look for XML parsing via JS, the vast majority of examples will be
DOM-based and/or browser specific.  We don't have the DOM around here.  It's
possible that you'd be able to find a pure-JS parser if you looked, which may
or may not be portable for Synchronet with some effort.

> For reference, I am trying to grab the data found here:
> http://www.hamqsl.com/solarxml.php

There's already some code for dealing with this exact feed, but it's embedded
in an IRC bot.  You might be able to find something useful in:
'/exec/ircbots/ham/ham.js', however this should work:

load('http.js');
try {
  var solardata = new XML(
    (new HTTPRequest()).Get(
      'http://www.hamqsl.com/solarxml.php'
    ).replace(
      /<\?[^?]*\?>/g, ''
    )
  ).solardata;
} catch (err) {
  log('Shit done borked! ' + err);
}

(See https://bbs.electronicchicken.com/temp/solar.txt if that didn't come
through okay.)

You should then be able to get at the values from the feed like so:

print(solardata.sunspots);
print(solardata.solarwind);

And so on.

The IRC bot code mentioned above has examples of how to deal with the nested
'calculated(vhf)conditions' values, which gets deeper into E4X than I care to
do right now.

Hope this helps.

---
echicken 
electronic chicken bbs - bbs.electronicchicken.com - 416-273-7230
 þ Synchronet þ electronic chicken bbs - bbs.electronicchicken.com

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