feeder - parse RSS and Atom

The feeder Erlang library parses RSS and Atom formatted XML feeds. It is a stream based parser that sends its events through a callback interface.

Usage

Parse a file and accumulate parser events:

-module(acc).
-export([file/1]).

event({entry, Entry}, {Feed, Entries}) ->
  {Feed, [Entry|Entries]};
event({feed, Feed}, {[], Entries}) ->
  {Feed, Entries};
event(endFeed, {Feed, Entries}) ->
  {Feed, lists:reverse(Entries)}.

opts() ->
  [{event_state, {[],[]}}, {event_fun, fun event/2}].

file(Filename) ->
  {ok, EventState, _Rest} = feeder:file(Filename, opts()),
  EventState.

Example

To try HTTP streaming do:

cd example
make
erl -pa ebin deps/*/ebin

fedex:start().
fedex:fetch("http://rss.nytimes.com/services/xml/rss/nyt/HomePage.xml").

Types

feed()

The channel or feed tuple.

enclosure()

The enclosure tuple for an item or entry.

entry()

An item or entry tuple.

option()

Options to setup the parser.

{continuation_fun, ContinuationFun} ContinuationFun is a call back function to decide what to do if the parser runs into EOF before the document is complete.

{continuation_state, term()} State that is accessible in the continuation call back function.

{event_fun, EventFun} EventFun is the call back function for parser events.

{event_state, term()} State that is accessible in the event call back function.

event()

The events that are sent to the user via the callback.

{feed, Feed}

• Feed = feed()

Receive notification when the meta information of the feed or channel has been parsed.

{entry, Entry}

• Entry = entry()

Receive notification for each entry or article in the feed.

endFeed

Receive notification of the end of a document. feeder will send this event only once, and it will be the last event during the parse.

Exports

Parsing feeds

feeder:file(Filename, Opts) -> Result

• Filename = string()
• Opts = [option()]
• Result = {ok, EventState, Rest}
• Rest = unicode_binary() | latin1_binary()
• EventState = term()

feeder:stream(Xml, Opts) -> Result

• Xml = unicode_binary() | latin1_binary() | [unicode_char()]
• Opts = [option()]
• Result = {ok, EventState, Rest}
• Rest = unicode_binary() | latin1_binary()
• EventState = term()

Accessing values

feeder_feeds:get(Key, Feed) -> Value

• Key = author | id | image | language | link | subtitle | summary | title | updated | url
• Feed = feed()
• Value = binary() | undefined

feeder_enclosures:get(Key, Enclosure) -> Value

• Key = url | length | type
• Enclosure = enclosure()
• Value = binary() | undefined

feeder_entries:get(Key, Entry) -> Value

• Key = author | categories | duration | enclosure | id | image | link | subtitle | summary | title | updated
• Entry = entry()
• Value = binary() | enclosure() | undefined

Tests

$ make tests

Install

You can install feeder with Rebar3, of course, and there are hex and erlang.mk packages.

License

MIT License