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koreader/frontend/ui/wikipedia.lua

86 lines
2.4 KiB
Lua

local JSON = require("JSON")
local DEBUG = require("dbg")
--[[
-- Query wikipedia using Wikimedia Web API.
-- http://en.wikipedia.org/w/api.php?action=query&prop=extracts&format=json&exintro=&explaintext=&redirects=&titles=hello
--]]
local Wikipedia = {
wiki_server = "http://%s.wikipedia.org",
wiki_path = "/w/api.php",
wiki_params = {
action = "query",
prop = "extracts",
format = "json",
exintro = "",
explaintext = "",
redirects = "",
},
default_lang = "en",
}
function Wikipedia:getWikiServer(lang)
return string.format(self.wiki_server, lang or self.default_lang)
end
--[[
-- return decoded JSON table from Wikipedia
--]]
function Wikipedia:loadPage(text, lang, intro, plain)
local socket = require('socket')
local url = require('socket.url')
local http = require('socket.http')
local https = require('ssl.https')
local ltn12 = require('ltn12')
local request, sink = {}, {}
local query = ""
self.wiki_params.exintro = intro and "" or nil
self.wiki_params.explaintext = plain and "" or nil
for k,v in pairs(self.wiki_params) do
query = query .. k .. '=' .. v .. '&'
end
local parsed = url.parse(self:getWikiServer(lang))
parsed.path = self.wiki_path
parsed.query = query .. "titles=" .. url.escape(text)
-- HTTP request
request['url'] = url.build(parsed)
request['method'] = 'GET'
request['sink'] = ltn12.sink.table(sink)
DEBUG("request", request)
http.TIMEOUT, https.TIMEOUT = 10, 10
local httpRequest = parsed.scheme == 'http' and http.request or https.request
local code, headers, status = socket.skip(1, httpRequest(request))
-- raise error message when network is unavailable
if headers == nil then
error("Network is unreachable")
end
local content = table.concat(sink)
if content ~= "" then
local ok, result = pcall(JSON.decode, JSON, content)
if ok and result then
DEBUG("wiki result", result)
return result
else
DEBUG("error:", result)
end
end
end
-- extract intro passage in wiki page
function Wikipedia:wikintro(text, lang)
local result = self:loadPage(text, lang, true, true)
if result then
local query = result.query
if query then
return query.pages
end
end
end
return Wikipedia