opmlparser

v0.8.0

Published

2 years ago

OPML parsing using sax js

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danmactough

opml feed outline xml syndication

Opmlparser - OPML parsing in Node.js

This module adds methods for OPML parsing in node.js using Isaac Schlueter's sax parser.

Requirements

sax
readable-stream (only if using Node <= v0.8.x)

Installation

npm install opmlparser

Changes since v0.5.x

The libxml-like helper methods have been removed. There is now just one input interface: the stream interface.
The addmeta option was removed, as it is unnecessary and only adds bloat.
Events:
- 304, response - removed, as Opmlparser no longer fetches urls
- meta, outline, feed, complete - removed; use the stream interface
- data - all readable streams will emit a data event, but this puts the stream into "old" v0.8-style push streams
- end - stream behavior dictates that the end event will never fire if you don't read any data from the stream; you can kick the Opmlparser stream to work like an "old" v0.8-style push stream (and get the old end event behavior) by calling .resume().
SAXErrors are emitted as error events. By default, they are automatically resumed. Pass { resume_saxerror: false } as an option if you want to manually handle SAXErrors (abort parsing, perhaps).


var OpmlParser = require('opmlparser')
  , request = require('request');

var req = request('http://someopmlurl.opml');
var opmlparser = new OpmlParser([options]);

req.on('error', function (error) {
  // handle any request errors
});
req.on('response', function (res) {
  var stream = this;

  if (res.statusCode != 200) return this.emit('error', new Error('Bad status code'));

  stream.pipe(opmlparser);
});


opmlparser.on('error', function(error) {
  // always handle errors
});
opmlparser.on('readable', function() {
  var stream = this
    , meta = this.meta // **NOTE** the "meta" is always available in the context of the opmlparser instance
    , outline;

  while (outline = stream.read()) {
    console.log(outline);
  }
});

options

opmlurl - The url (string) of the OPML. Opmlparser is very good at resolving relative urls in OPML files. But OPML files could use relative urls without declaring the xml:base attribute any place in the file. This is perfectly valid, but we don't know know the file's url before we start parsing the file and trying to resolve those relative urls. If we discover the file's url, we will go back and resolve the relative urls we've already seen, but this takes a little time (not much). If you want to be sure we never have to re- resolve relative urls (or if Opmlparser is failing to properly resolve relative urls), you should set the opmlurl option. Otherwise, feel free to ignore this option.
resume_saxerror - Set to false to override Opmlparser's default behavior, which is to emit any SAXError on error and then automatically resume parsing. In my experience, SAXErrors are not usually fatal, so this is usually helpful behavior. If you want total control over handling these errors and optionally aborting parsing the OPML, use this option.

Examples

See the examples directory.

API

Transform Stream

Opmlparser is a transform stream operating in "object mode": XML in -> Javascript objects out. Each readable chunk is an object representing an <outline> element in the OPML.

What is the parsed output produced by opmlparser?

Opmlparser parses each OPML file into readable outline chunks, as well as a meta object.

The meta will be the information in the OPML's <head> element, plus some additional metadata, such as OPML version, any namespaces defined, etc.

Each outline chunk will simply translate an <outline> element in the OPML's <body> from XML to a Javascript object. Each chunk is assigned a simple counter-based id when it is parsed and references its immediate ancestor's id, which will allow you to recreate the tree if you want.

List of meta propreties

No validation is performed. Each of the meta properties will be defined, but any of them may be null.

title
datecreated
datemodified
ownername
ownerid
docs
expansionstate
vertscrollstate
windowtop
windowleft
windowbottom
windowright

List of outline properties

No validation is performed. Any or all of the following properties may be absent, and other arbitrary (and invalid) properties may be present.

title
text
xmlurl
htmlurl
description
type
language
version

See the OPML Spec for more info about what to expect to see in various kinds of OPML files.

In addition, Opmlparser adds the following properties:

#id - this outline element's id
#parentid - this id of this outline element's immediate ancestor
#type (optional) - this outline element contains a feed

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.