lib/oembed/formatter.rb
require 'oembed/formatter/base'
require 'oembed/formatter/json'
require 'oembed/formatter/xml'
module OEmbed
# Takes the raw response from an oEmbed server and turns it into a nice Hash of data.
module Formatter
class << self
# Returns the default format for OEmbed::Provider requests as a String.
def default
# Listed in order of preference.
%w{json xml}.detect { |type| supported?(type) rescue false }
end
# Given the name of a format we want to know about (e.g. 'json'), returns
# true if there is a valid backend. If there is no backend, raises
# OEmbed::FormatNotSupported.
def supported?(format)
case format.to_s
when 'json'
JSON.supported?
when 'xml'
XML.supported?
else
raise OEmbed::FormatNotSupported, format
end
end
# Convert the given value into a nice Hash of values. The format should
# be the name of the response format (e.g. 'json'). The value should be
# a String or IO containing the response from an oEmbed server.
#
# For example:
# value = '{"version": "1.0", "type": "link", "title": "Some Cool News Article"}'
# OEmbed::Formatter.decode('json', value)
# #=> {"version": "1.0", "type": "link", "title": "Some Cool News Article"}
def decode(format, value)
supported?(format)
begin
case format.to_s
when 'json'
begin
JSON.decode(value)
rescue JSON.backend.parse_error
raise OEmbed::ParseError, $!.message
end
when 'xml'
begin
XML.decode(value)
rescue XML.backend.parse_error
raise OEmbed::ParseError, $!.message
end
end
rescue
raise OEmbed::ParseError, "#{$!.class}: #{$!.message}"
end
end
# Test the given backend to make sure it parses known values correctly.
# The backend_module should be either a JSON or XML backend.
def test_backend(backend_module)
expected = {
"version"=>1.0,
"string"=>"test",
"int"=>42,
"html"=>"<i>Cool's</i>\n the \"word\"!",
}
given_value = case backend_module.to_s
when /OEmbed::Formatter::JSON::Backends::/
<<-JSON
{"version":"1.0", "string":"test", "int":42,"html":"<i>Cool's</i>\\n the \\"word\\"\\u0021"}
JSON
when /OEmbed::Formatter::XML::Backends::/
<<-XML
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<oembed>
<version>1.0</version>
<string>test</string>
<int>42</int>
<html><i>Cool's</i>\n the "word"!</html>
</oembed>
XML
else
nil
end
actual = backend_module.decode(given_value)
# For the test to be true the actual output Hash should have the
# exact same list of keys _and_ the values should be the same
# if we ignoring typecasting.
actual.keys.sort == expected.keys.sort &&
!actual.detect { |key, value| value.to_s != expected[key].to_s }
end
end # self
end
end