feed_parser/lib/feed_parser.ex

46 lines
1.3 KiB
Elixir

defmodule FeedParser do
@moduledoc """
FeedParser is a for parsing feeds of various formats into a unified representation.
The currently supported formats are:
- RSS 2.0
- Atom
- JSON Feed
- RSS-in-JSON
"""
@default_parsers [
FeedParser.Parser.RSS2,
FeedParser.Parser.Atom,
FeedParser.Parser.JSONFeed,
FeedParser.Parser.RSSInJSON
]
@doc """
Parses a feed from the given data string and MIME type.
An extended set of parsers may also be provided, otherwise the default set (supporting RSS 2.0, Atom, JSON Feed, and RSS-in-JSON) will be used. Parsers are modules that implement the `FeedParser.Parser` behaviour.
"""
@spec parse(data :: String.t(), content_type :: String.t(), parsers :: [module()]) ::
{:ok, feed :: FeedParser.Feed.t()} | {:error, reason :: String.t()}
def parse(data, content_type, parsers \\ @default_parsers) when is_binary(data) do
parsers
|> Enum.reduce_while(false, fn parser, acc ->
case parser.accepts(data, content_type) do
{true, result} ->
{:halt, {parser, result}}
_ ->
{:cont, acc}
end
end)
|> case do
{parser, result} ->
parser.parse_feed(result)
false ->
{:error, "no parser matched the given content type ('#{content_type}') and data"}
end
end
end