From 4a6b9b1816d8784693a5e81c19be687aff8b4bdc Mon Sep 17 00:00:00 2001
From: Andreas Bielawski <brawl98@outlook.com>
Date: Wed, 15 Jun 2016 18:00:59 +0200
Subject: [PATCH] Portierung folgender Plugins: - App Store - Bitly -
 Bitly_create - Expand - Facebook - GitHub

---
 otouto/plugins/app_store.lua    | 117 +++++++++++++++++++++
 otouto/plugins/bitly.lua        |  48 +++++++++
 otouto/plugins/bitly_create.lua | 142 +++++++++++++++++++++++++
 otouto/plugins/expand.lua       |  37 +++++++
 otouto/plugins/facebook.lua     | 180 ++++++++++++++++++++++++++++++++
 otouto/plugins/github.lua       |  77 ++++++++++++++
 otouto/utilities.lua            |  10 ++
 7 files changed, 611 insertions(+)
 create mode 100644 otouto/plugins/app_store.lua
 create mode 100644 otouto/plugins/bitly.lua
 create mode 100644 otouto/plugins/bitly_create.lua
 create mode 100644 otouto/plugins/expand.lua
 create mode 100644 otouto/plugins/facebook.lua
 create mode 100644 otouto/plugins/github.lua

diff --git a/otouto/plugins/app_store.lua b/otouto/plugins/app_store.lua
new file mode 100644
index 0000000..9be7eb1
--- /dev/null
+++ b/otouto/plugins/app_store.lua
@@ -0,0 +1,117 @@
+local app_store = {}
+
+local https = require('ssl.https')
+local json = require('dkjson')
+local utilities = require('otouto.utilities')
+local redis = (loadfile "./otouto/redis.lua")()
+
+app_store.triggers = {
+	"itunes.apple.com/(.*)/app/(.*)/id(%d+)",
+	"^!itunes (%d+)$",
+	"itunes.apple.com/app/id(%d+)"
+}
+	
+local BASE_URL = 'https://itunes.apple.com/lookup'
+
+local makeOurDate = function(dateString)
+  local pattern = "(%d+)%-(%d+)%-(%d+)T"
+  local year, month, day = dateString:match(pattern)
+  return day..'.'..month..'.'..year
+end
+
+function app_store:get_appstore_data()
+  local url = BASE_URL..'/?id='..appid..'&country=de'
+  local res,code  = https.request(url)
+  if code ~= 200 then return "HTTP-FEHLER" end
+  local data = json.decode(res).results[1]
+  
+  if data == nil then return 'NOTFOUND' end
+  if data.wrapperType ~= 'software' then return nil end
+  
+  return data
+end
+
+function app_store:send_appstore_data(data)  
+  -- Header
+  local name = data.trackName
+  local author = data.sellerName
+  local price = data.formattedPrice
+  local version = data.version
+  
+  -- Body
+  local description = string.sub(unescape(data.description), 1, 150) .. '...'
+  local min_ios_ver = data.minimumOsVersion
+  local size = string.gsub(round(data.fileSizeBytes / 1000000, 2), "%.", ",") -- wtf Apple, it's 1024, not 1000!
+  local release = makeOurDate(data.releaseDate)
+  if data.isGameCenterEnabled then
+    game_center = '\nUnterstützt Game Center'
+  else
+    game_center = ''
+  end
+  local category_count = tablelength(data.genres)
+  if category_count == 1 then
+    category = '\nKategorie: '..data.genres[1]
+  else
+    local category_loop = '\nKategorien: '
+    for v in pairs(data.genres) do
+      if v < category_count then
+        category_loop = category_loop..data.genres[v]..', '
+	  else
+	    category_loop = category_loop..data.genres[v]
+	  end
+    end
+	  category = category_loop
+  end
+  
+  -- Footer
+  if data.averageUserRating and data.userRatingCount then
+    avg_rating = 'Bewertung: '..string.gsub(data.averageUserRating, "%.", ",")..' Sterne '
+	ratings = 'von '..comma_value(data.userRatingCount)..' Bewertungen'
+  else
+    avg_rating = ""
+	ratings = ""
+  end
+  
+  
+  local header = '*'..name..'* v'..version..' von *'..author..'* ('..price..'):'
+  local body = '\n'..description..'\n_Benötigt mind. iOS '..min_ios_ver..'_\nGröße: '..size..' MB\nErstveröffentlicht am '..release..game_center..category
+  local footer = '\n'..avg_rating..ratings
+  local text = header..body..footer
+  
+  -- Picture
+  if data.screenshotUrls[1] and data.ipadScreenshotUrls[1] then
+    image_url = data.screenshotUrls[1]
+  elseif data.screenshotUrls[1] and not data.ipadScreenshotUrls[1] then
+    image_url = data.screenshotUrls[1]
+  elseif not data.screenshotUrls[1] and data.ipadScreenshotUrls[1] then
+    image_url = data.ipadScreenshotUrls[1]
+  else
+    image_url = nil
+  end
+  
+  return text, image_url
+end
+
+function app_store:action(msg, config, matches)
+  if not matches[3] then
+    appid = matches[1]
+  else
+    appid = matches[3]
+  end
+  local data = app_store:get_appstore_data()
+  if data == nil then print('Das Appstore-Plugin unterstützt nur Apps!') end
+  if data == 'HTTP-FEHLER' or data == 'NOTFOUND' then
+    utilities.send_reply(self, msg, '*App nicht gefunden!*', true)
+    return
+  else
+    local output, image_url = app_store:send_appstore_data(data)
+    utilities.send_reply(self, msg, output, true)
+	if image_url then
+	  utilities.send_typing(self, msg.chat.id, 'upload_photo')
+	  local file = download_to_file(image_url)
+	  utilities.send_photo(self, msg.chat.id, file, nil, msg.message_id)
+	end
+  end
+end
+
+return app_store
diff --git a/otouto/plugins/bitly.lua b/otouto/plugins/bitly.lua
new file mode 100644
index 0000000..d1f9653
--- /dev/null
+++ b/otouto/plugins/bitly.lua
@@ -0,0 +1,48 @@
+local bitly = {}
+
+local https = require('ssl.https')
+local json = require('dkjson')
+local utilities = require('otouto.utilities')
+local redis = (loadfile "./otouto/redis.lua")()
+
+function bitly:init(config)
+  if not cred_data.bitly_access_token then
+    print('Missing config value: bitly_access_token.')
+    print('bitly.lua will not be enabled.')
+    return
+  end
+
+  bitly.triggers = {
+	"bit.ly/([A-Za-z0-9-_-]+)",
+	"bitly.com/([A-Za-z0-9-_-]+)",
+	"j.mp/([A-Za-z0-9-_-]+)",
+	"andib.tk/([A-Za-z0-9-_-]+)"
+  }
+end
+	
+local BASE_URL = 'https://api-ssl.bitly.com/v3/expand'
+
+function bitly:expand_bitly_link (shorturl)
+  local access_token = cred_data.bitly_access_token
+  local url = BASE_URL..'?access_token='..access_token..'&shortUrl=https://bit.ly/'..shorturl
+  local res,code  = https.request(url)
+  if code ~= 200 then return "HTTP-FEHLER" end
+  local data = json.decode(res).data.expand[1]
+  cache_data('bitly', shorturl, data)
+  return data.long_url
+end
+
+function bitly:action(msg, config, matches)
+  local shorturl = matches[1]
+  local hash = 'telegram:cache:bitly:'..shorturl
+  if redis:exists(hash) == false then
+    utilities.send_reply(self, msg, bitly:expand_bitly_link(shorturl))
+    return
+  else
+    local data = redis:hgetall(hash)
+	utilities.send_reply(self, msg, data.long_url)
+	return
+  end
+end
+
+return bitly
diff --git a/otouto/plugins/bitly_create.lua b/otouto/plugins/bitly_create.lua
new file mode 100644
index 0000000..1b34ff1
--- /dev/null
+++ b/otouto/plugins/bitly_create.lua
@@ -0,0 +1,142 @@
+local bitly_create = {}
+
+local http = require('socket.http')
+local https = require('ssl.https')
+local URL = require('socket.url')
+local json = require('dkjson')
+local utilities = require('otouto.utilities')
+local bindings = require('otouto.bindings')
+local OAuth = require "OAuth"
+local redis = (loadfile "./otouto/redis.lua")()
+
+function bitly_create:init(config)
+	if not cred_data.bitly_client_id then
+		print('Missing config value: bitly_client_id.')
+		print('bitly_create.lua will not be enabled.')
+		return
+	elseif not cred_data.bitly_client_secret then
+		print('Missing config value: bitly_client_secret.')
+		print('bitly_create.lua will not be enabled.')
+		return
+	elseif not cred_data.bitly_redirect_uri then
+		print('Missing config value: bitly_redirect_uri.')
+		print('bitly_create.lua will not be enabled.')
+		return
+	end
+
+    bitly_create.triggers = {
+    "^/short (auth) (.+)$",
+    "^/short (auth)$",
+	"^/short (unauth)$",
+	"^/short (me)$",
+  	"^/short (j.mp) (https?://[%w-_%.%?%.:/%+=&]+)$",
+	"^/short (bit.ly) (https?://[%w-_%.%?%.:/%+=&]+)$",
+	"^/short (bitly.com) (https?://[%w-_%.%?%.:/%+=&]+)$",
+	"^/short (https?://[%w-_%.%?%.:/%+=&]+)$"
+	}
+	bitly_create.doc = [[*
+]]..config.cmd_pat..[[short* _<Link>_: Kürzt einen Link mit der Standard Bitly-Adresse
+*]]..config.cmd_pat..[[short* _<j.mp|bit.ly|bitly.com>_ _[Link]_: Kürzt einen Link mit der ausgewählten Kurz-URL
+*]]..config.cmd_pat..[[short* _auth_: Loggt deinen Account ein und nutzt ihn für deine Links (empfohlen!)
+*]]..config.cmd_pat..[[short* _me_: Gibt den eingeloggten Account aus
+*]]..config.cmd_pat..[[short* _unauth_: Loggt deinen Account aus
+]]
+end
+
+bitly_create.command = 'short <URL>'
+
+local BASE_URL = 'https://api-ssl.bitly.com'
+
+local client_id = cred_data.bitly_client_id
+local client_secret = cred_data.bitly_client_secret
+local redirect_uri = cred_data.bitly_redirect_uri
+
+function bitly_create:get_bitly_access_token(hash, code)
+  local req = post_petition(BASE_URL..'/oauth/access_token', 'client_id='..client_id..'&client_secret='..client_secret..'&code='..code..'&redirect_uri='..redirect_uri)
+  if not req.access_token then return '*Fehler beim Einloggen!*' end
+  
+  local access_token = req.access_token
+  local login_name = req.login
+  redis:hset(hash, 'bitly', access_token)
+  return 'Erfolgreich als `'..login_name..'` eingeloggt!'
+end
+
+function bitly_create:get_bitly_user_info(bitly_access_token)
+  local url = BASE_URL..'/v3/user/info?access_token='..bitly_access_token..'&format=json'
+  local res,code  = https.request(url)
+  if code == 401 then return 'Login fehlgeschlagen!' end
+  if code ~= 200 then return 'HTTP-Fehler!' end
+  
+  local data = json.decode(res).data
+  
+  if data.full_name then
+    name = '*'..data.full_name..'* (`'..data.login..'`)'
+  else
+    name = '`'..data.login..'`'
+  end
+  
+  local text = 'Eingeloggt als '..name
+  
+  return text
+end
+
+function bitly_create:create_bitlink (long_url, domain, bitly_access_atoken)
+  local url = BASE_URL..'/v3/shorten?access_token='..bitly_access_token..'&domain='..domain..'&longUrl='..long_url..'&format=txt'
+  local text,code  = https.request(url)
+  if code ~= 200 then return 'FEHLER: '..text end
+  return text
+end
+
+function bitly_create:action(msg, config, matches)
+  local hash = 'user:'..msg.from.id
+  bitly_access_token = redis:hget(hash, 'bitly')
+  
+  if matches[1] == 'auth' and matches[2] then
+    utilities.send_reply(self, msg, bitly_create:get_bitly_access_token(hash, matches[2]), true)
+    return
+  end
+  
+  if matches[1] == 'auth' then
+    utilities.send_reply(self, msg, 'Bitte logge dich ein und folge den Anweisungen:\n[Bei Bitly anmelden](https://bitly.com/oauth/authorize?client_id='..client_id..'&redirect_uri='..redirect_uri..')', true)
+    return
+  end
+  
+  if matches[1] == 'unauth' and bitly_access_token then
+    redis:hdel(hash, 'bitly')
+	utilities.send_reply(self, msg, '*Erfolgreich ausgeloggt!* Du kannst den Zugriff [in deinen Kontoeinstellungen](https://bitly.com/a/settings/connected) endgültig entziehen.', true)
+	return
+  elseif matches[1] == 'unauth' and not bitly_access_token then
+    utilities.send_reply(self, msg, 'Wie willst du dich ausloggen, wenn du gar nicht eingeloggt bist?', true)
+    return
+  end
+  
+  if matches[1] == 'me' and bitly_access_token then
+    local text = bitly_create:get_bitly_user_info(bitly_access_token)
+	if text then
+	  utilities.send_reply(self, msg, text, true)
+	  return
+	else
+	  return
+	end
+  elseif matches[1] == 'me' and not bitly_access_token then
+    utilities.send_reply(self, msg, 'Du bist nicht eingeloggt! Logge dich ein mit\n/short auth', true)
+    return
+  end
+
+  if not bitly_access_token then
+    print('Not signed in, will use global bitly access_token')
+    bitly_access_token = cred_data.bitly_access_token
+  end
+  
+  if matches[2] == nil then
+    long_url = url_encode(matches[1])
+	domain = 'bit.ly'
+  else
+    long_url = url_encode(matches[2])
+	domain = matches[1]
+  end
+  utilities.send_reply(self, msg, bitly_create:create_bitlink(long_url, domain, bitly_access_token))
+  return
+end
+
+return bitly_create
\ No newline at end of file
diff --git a/otouto/plugins/expand.lua b/otouto/plugins/expand.lua
new file mode 100644
index 0000000..60b056e
--- /dev/null
+++ b/otouto/plugins/expand.lua
@@ -0,0 +1,37 @@
+local expand = {}
+
+local http = require('socket.http')
+local utilities = require('otouto.utilities')
+
+function expand:init(config)
+  expand.triggers = {
+    "^/expand (https?://[%w-_%.%?%.:/%+=&]+)$"
+  }
+
+  expand.doc = [[*
+]]..config.cmd_pat..[[expand* _<Kurz-URL>_: Verlängert Kurz-URL (301er/302er)]]
+end
+
+expand.command = 'expand <Kurz-URL>'
+
+function expand:action(msg, config, matches)
+   local response_body = {}
+   local request_constructor = {
+      url = matches[1],
+      method = "HEAD",
+      sink = ltn12.sink.table(response_body),
+      headers = {},
+      redirect = false
+   }
+
+   local ok, response_code, response_headers, response_status_line = http.request(request_constructor)
+   if ok and response_headers.location then
+      utilities.send_reply(self, msg, response_headers.location)
+      return
+   else
+      utilities.send_reply(self, msg, "Fehler beim Erweitern der URL.")
+      return
+   end
+end
+
+return expand
diff --git a/otouto/plugins/facebook.lua b/otouto/plugins/facebook.lua
new file mode 100644
index 0000000..2bbd215
--- /dev/null
+++ b/otouto/plugins/facebook.lua
@@ -0,0 +1,180 @@
+local facebook = {}
+
+local http = require('socket.http')
+local https = require('ssl.https')
+local URL = require('socket.url')
+local json = require('dkjson')
+local utilities = require('otouto.utilities')
+local bindings = require('otouto.bindings')
+local redis = (loadfile "./otouto/redis.lua")()
+
+function facebook:init(config)
+	if not cred_data.fb_access_token then
+		print('Missing config value: fb_access_token.')
+		print('facebook.lua will not be enabled.')
+		return
+	end
+
+    facebook.triggers = {
+	  "facebook.com/([A-Za-z0-9-._-]+)/(posts)/(%d+)",
+	  "facebook.com/(permalink).php%?(story_fbid)=(%d+)&id=(%d+)",
+      "facebook.com/(photo).php%?fbid=(%d+)",
+      "facebook.com/([A-Za-z0-9-._-]+)/(photos)/a.(%d+[%d%.]*)/(%d+)",
+      "facebook.com/(video).php%?v=(%d+)",
+	  "facebook.com/([A-Za-z0-9-._-]+)/(videos)/(%d+[%d%.]*)",
+	  "facebook.com/([A-Za-z0-9-._-]+)"
+	}
+end
+
+local BASE_URL = 'https://graph.facebook.com/v2.5'
+local fb_access_token = cred_data.fb_access_token
+
+local makeOurDate = function(dateString)
+  local pattern = "(%d+)%/(%d+)%/(%d+)"
+  local month, day, year = dateString:match(pattern)
+  return day..'.'..month..'.'..year
+end
+
+function facebook:get_fb_id(name)
+  local url = BASE_URL..'/'..name..'?access_token='..fb_access_token..'&locale=de_DE'
+  local res,code  = https.request(url)
+  if code ~= 200 then return nil end
+  local data = json.decode(res)
+  return data.id
+end
+
+function facebook:fb_post (id, story_id)
+  local url = BASE_URL..'/'..id..'_'..story_id..'?access_token='..fb_access_token..'&locale=de_DE&fields=from,name,story,message,link'
+  local res,code  = https.request(url)
+  if code ~= 200 then return nil end
+  local data = json.decode(res)
+  
+  local from = data.from.name
+  local message = data.message
+  local name = data.name
+  if data.link then
+    link = '\n'..data.name..':\n'..data.link
+  else
+    link = ""
+  end
+  
+  if data.story then
+    story = ' ('..data.story..')'
+  else
+    story = ""
+  end
+  
+  local text = '*'..from..'*'..story..':\n'..message..'\n'..link
+  return text
+end
+
+function facebook:send_facebook_photo(photo_id, receiver)
+  local url = BASE_URL..'/'..photo_id..'?access_token='..fb_access_token..'&locale=de_DE&fields=images,from,name'
+  local res,code  = https.request(url)
+  if code ~= 200 then return nil end
+  local data = json.decode(res)
+  
+  local from = '*'..data.from.name..'*'
+  if data.name then
+    text = from..' hat ein Bild gepostet:\n'..data.name
+  else
+    text = from..' hat ein Bild gepostet:'
+  end
+  local image_url = data.images[1].source
+  return text, image_url
+end
+
+function facebook:send_facebook_video(video_id)
+  local url = BASE_URL..'/'..video_id..'?access_token='..fb_access_token..'&locale=de_DE&fields=description,from,source,title'
+  local res,code  = https.request(url)
+  if code ~= 200 then return nil end
+  local data = json.decode(res)
+
+  local from = '*'..data.from.name..'*'
+  local description = data.description
+  local source = data.source
+  if data.title then
+    text = from..' hat ein Video gepostet:\n'..description..'\n['..data.title..']('..source..')'
+  else
+    text = from..' hat ein Video gepostet:\n'..description..'\n'..utilities.md_escape(source)
+  end
+  return text
+end
+
+function facebook:facebook_info(name)
+  local url = BASE_URL..'/'..name..'?access_token='..fb_access_token..'&locale=de_DE&fields=about,name,birthday,category,founded,general_info,is_verified'
+  local res,code  = https.request(url)
+  if code ~= 200 then return nil end
+  local data = json.decode(res)
+  
+  local name = data.name
+  if data.is_verified then
+    name = name..' ✅'
+  end
+  
+  local category = data.category
+  
+  if data.about then
+    about = '\n'..data.about
+  else
+    about = ""
+  end
+  
+  if data.general_info then
+    general_info = '\n'..data.general_info
+  else
+    general_info = ""
+  end
+  
+  if data.birthday and data.founded then
+    birth = '\nGeburtstag: '..makeOurDate(data.birthday)
+  elseif data.birthday and not data.founded then
+    birth = '\nGeburtstag: '..makeOurDate(data.birthday)
+  elseif data.founded and not data.birthday then
+    birth = '\nGegründet: '..data.founded
+  else
+    birth = ""
+  end
+  
+  local text = '*'..name..'* ('..category..')_'..about..'_'..general_info..birth
+  return text
+end
+
+function facebook:action(msg, config, matches)
+  if matches[1] == 'permalink' or matches[2] == 'posts' then
+    story_id = matches[3]
+    if not matches[4] then
+	  id = facebook:get_fb_id(matches[1])
+	else
+	  id = matches[4]
+	end
+	utilities.send_reply(self, msg, facebook:fb_post(id, story_id), true)
+    return
+  elseif matches[1] == 'photo' or matches[2] == 'photos' then
+    if not matches[4] then
+      photo_id = matches[2]
+    else
+      photo_id = matches[4]
+    end
+	utilities.send_typing(self, msg.chat.id, 'upload_photo')
+    local text, image_url = facebook:send_facebook_photo(photo_id, receiver)
+	local file = download_to_file(image_url)
+	utilities.send_reply(self, msg, text, true)
+	utilities.send_photo(self, msg.chat.id, file, nil, msg.message_id)
+	return
+  elseif matches[1] == 'video' or matches[2] == 'videos' then
+    if not matches[3] then
+      video_id = matches[2]
+    else
+      video_id = matches[3]
+    end
+    local output = facebook:send_facebook_video(video_id)
+	utilities.send_reply(self, msg, output, true)
+	return
+  else
+    utilities.send_reply(self, msg, facebook:facebook_info(matches[1]), true)
+    return
+  end
+end
+
+return facebook
\ No newline at end of file
diff --git a/otouto/plugins/github.lua b/otouto/plugins/github.lua
new file mode 100644
index 0000000..a29328e
--- /dev/null
+++ b/otouto/plugins/github.lua
@@ -0,0 +1,77 @@
+local github = {}
+
+local http = require('socket.http')
+local https = require('ssl.https')
+local URL = require('socket.url')
+local json = require('dkjson')
+local utilities = require('otouto.utilities')
+local bindings = require('otouto.bindings')
+local redis = (loadfile "./otouto/redis.lua")()
+
+function github:init(config)
+    github.triggers = {
+      "github.com/([A-Za-z0-9-_-.-._.]+)/([A-Za-z0-9-_-.-._.]+)/commit/([a-z0-9-]+)",
+      "github.com/([A-Za-z0-9-_-.-._.]+)/([A-Za-z0-9-_-.-._.]+)/?$"
+	}
+end
+
+local BASE_URL = 'https://api.github.com'
+
+function github:get_gh_data(gh_code, gh_commit_sha)
+  if gh_commit_sha == nil then
+    url = BASE_URL..'/repos/'..gh_code
+  else
+    url = BASE_URL..'/repos/'..gh_code..'/git/commits/'..gh_commit_sha
+  end
+  local res,code  = https.request(url)
+  if code ~= 200 then return "HTTP-FEHLER" end
+  local data = json.decode(res)
+  return data
+end
+
+function github:send_github_data(data)
+  if not data.owner then return nil end
+  local name = '*'..data.name..'*'
+  local description = '_'..data.description..'_'
+  local owner = data.owner.login
+  local clone_url = data.clone_url
+  if data.language == nil or data.language == "" then
+    language = ''
+  else
+    language = '\nSprache: '..data.language
+  end
+  if data.open_issues_count == 0 then
+    issues = ''
+  else
+    issues = '\nOffene Bugreports: '..data.open_issues_count
+  end
+  if data.homepage == nil or data.homepage == "" then
+    homepage = ''
+  else
+    homepage = '\n[Homepage besuchen]('..data.homepage..')'
+  end
+  local text = name..' von '..owner..'\n'..description..'\n`git clone '..clone_url..'`'..language..issues..homepage
+  return text
+end
+
+function github:send_gh_commit_data(gh_code, gh_commit_sha, data)
+  if not data.committer then return nil end
+  local committer = data.committer.name
+  local message = data.message
+  local text = '`'..gh_code..'@'..gh_commit_sha..'` von *'..committer..'*:\n'..message
+  return text
+end
+
+function github:action(msg, config, matches)
+  local gh_code = matches[1]..'/'..matches[2]
+  local gh_commit_sha = matches[3]
+  local data = github:get_gh_data(gh_code, gh_commit_sha)
+  if not gh_commit_sha then
+    output = github:send_github_data(data)
+  else
+    output = github:send_gh_commit_data(gh_code, gh_commit_sha, data)
+  end
+  utilities.send_reply(self, msg, output, true)
+end
+
+return github
\ No newline at end of file
diff --git a/otouto/utilities.lua b/otouto/utilities.lua
index cec8851..27fd9f8 100644
--- a/otouto/utilities.lua
+++ b/otouto/utilities.lua
@@ -821,4 +821,14 @@ function unescape(str)
   return str
 end
 
+function url_encode(str)
+  if (str) then
+    str = string.gsub (str, "\n", "\r\n")
+    str = string.gsub (str, "([^%w %-%_%.%~])",
+        function (c) return string.format ("%%%02X", string.byte(c)) end)
+    str = string.gsub (str, " ", "+")
+  end
+  return str
+end
+
 return utilities