summaryrefslogtreecommitdiff
path: root/plugins/degesch/last-fm.lua
blob: 54f5d1c2a17cc36e19d927ad7ecd1cc9917abc58 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
--
-- last-fm.lua: "now playing" feature using the last.fm API
--
-- Dependencies: lua-cjson (from luarocks e.g.)
--
-- I call this style closure-oriented programming
--
-- Copyright (c) 2016, Přemysl Janouch <p.janouch@gmail.com>
--
-- Permission to use, copy, modify, and/or distribute this software for any
-- purpose with or without fee is hereby granted, provided that the above
-- copyright notice and this permission notice appear in all copies.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
-- SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
-- OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
-- CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
--

local cjson = require "cjson"

-- Setup configuration to load last.fm API credentials from
local user, api_key
degesch.setup_config {
	user    = {
		type = "string",
		comment = "last.fm username",
		on_change = function (v) user    = v end
	},
	api_key = {
		type = "string",
		comment = "last.fm API key",
		on_change = function (v) api_key = v end
	},
}

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

-- Generic error reporting
local report_error = function (buffer, error)
	buffer:log ("last-fm error: " .. error)
end

-- Process data return by the server and extract the now playing song
local process = function (buffer, data)
	-- There's no reasonable Lua package to parse HTTP that I could find
	local s, e, v, status, message = string.find (data, "(%S+) (%S+) (%S+)\r\n")
	if not s then return "server returned unexpected data" end
	if status ~= "200" then return status .. " " .. message end

	local s, e = string.find (data, "\r\n\r\n")
	if not s then return "server returned unexpected data" end

	local parser = cjson.new ()
	data = parser.decode (string.sub (data, e + 1))
	if not data.recenttracks or not data.recenttracks.track then
		return "invalid response" end

	-- Need to make some sense of the XML automatically converted to JSON
	local text_of = function (node)
		if type (node) == "table" then return node["#text"] end
		return node
	end

	local name, artist, album
	for i, track in ipairs (data.recenttracks.track) do
		if track["@attr"] and track["@attr"].nowplaying then
			if track.name   then name   = text_of (track.name)   end
			if track.artist then artist = text_of (track.artist) end
			if track.album  then album  = text_of (track.album)  end
		end
	end

	if not name then
		buffer:log ("Not playing anything right now")
	else
		local np = "Now playing: \"" .. name .. "\""
		if artist then np = np .. " by "   .. artist end
		if album  then np = np .. " from " .. album  end
		buffer:log (np)
	end
end

-- Set up the connection and make the request
local on_connected = function (buffer, c, host)
	-- Buffer data in the connection object
	c.data = ""
	c.on_data = function (data)
		c.data = c.data .. data
	end

	-- And process it after we receive everything
	c.on_eof = function ()
		error = process (buffer, c.data)
		if error then report_error (buffer, error) end
		c:close ()
	end
	c.on_error = function (e)
		report_error (buffer, e)
	end

	-- Make the unencrypted HTTP request
	local url = "/2.0/?method=user.getrecenttracks&user=" .. user ..
		"&limit=1&api_key=" .. api_key .. "&format=json"
	c:send ("GET " .. url .. " HTTP/1.1\r\n")
	c:send ("User-agent: last-fm.lua\r\n")
	c:send ("Host: " .. host .. "\r\n")
	c:send ("Connection: close\r\n")
	c:send ("\r\n")
end

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

-- Avoid establishing more than one connection at a time
local running

-- Initiate a connection to last.fm servers
local make_request = function (buffer)
	if not user or not api_key then
		report_error (buffer, "configuration is incomplete")
		return
	end

	if running then running.abort () end

	running = degesch.connect ("ws.audioscrobbler.com", 80, {
		on_success = function (c, host)
			on_connected (buffer, c, host)
			running = nil
		end,
		on_error   = function (e)
			report_error (buffer, e)
			running = nil
		end
	})
end

-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

-- TODO:
--   /np? to just retrieve the song and print it in the buffer
--   /np! to execute "/me is listening to " .. last retrieved song
--   /np  to do both in succession

-- Hook input to simulate new commands
degesch.hook_input (function (hook, buffer, input)
	if input == "/np" then
		make_request (buffer)
	else
		return input
	end
end)