itchy/ReadMe.md
2018-05-25 16:32:09 -07:00

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# itchy
A super simple version checker for use with [LÖVE](https://love2d.org) games
published on [itch.io](https://itch.io/).
## Installation
Copy `itchy.lua` to where you want in your source. It is recommended that you
install [luajit-request](https://github.com/LPGhatguy/luajit-request) as it
allows for itchy to use HTTPS connections.
## Usage
Start it as a thread with a configuration table. Wait for "itchy" channel to
respond with a table of version information.
Require itchy, and run `check_version` with a configuration table. Periodically
run `new_version` to see if data has been returned yet.
```lua
local itchy = require "lib.itchy" -- or wherever you saved it
local game = {
target = "guard13007/asteroid-dodge", -- target or url must be defined
version = "1.0.0" -- optional, config options listed below
}
itchy:check_version(game)
-- somewhere where this will be called periodically
local data = itchy:new_version(game) -- passing the game table is not necessary
if data then
-- easiest usage, just print the message to the user
love.graphics.print("Version: 1.0.0 Latest: " .. data.message)
end
```
You can cancel it with `itchy:kill_version_checker(game)`, and start a new
version checker with `itchy:check_version({})` any time you like.
### Version Information Example
Returned data example:
```lua
{
status = 200, -- nil or status code of an HTTP request
body = '{"latest":"0.2.0"}', -- raw result body from the HTTP request
version = "0.2.0", -- number/string (if body was parsed correctly)
latest = true, -- nil/boolean: your version == latest version?
message = "0.2.0, you have the latest version" -- an error or status message
}
```
Errors from LuaSocket will be returned as `"socket.http.request error: " .. err`
The library tries to parse a response body for valid JSON of the format
`{"latest":"VERSION"}` (itch.io's format) and will do basic version comparisons
based on this value. If it is unable to extract it or compare, `version` and
`latest` will be `nil`.
If HTTP status 200 (OK) is encountered or a version is successfully parsed from
a response, the script terminates (or moves on to checking on an interval.)
Otherwise, it will keep trying with an exponential back-off starting at a 1
second delay, capped at retrying every 10 minutes.
### Configuration Options
At minimum a `url` or `target` must be specified.
* `url` (string) If you have a different URL to check for the latest version
from, you can specify it here.
* `target` (string) The target string of your game on itch.io
(username/game-slug).
* `channel` (string) If you do not specify the channel name to look for on
itch.io, it will use `osx` for Mac OS / OS X, `win32` for Windows, `linux` for
Linux, `android` for Android, `ios` for iOS, and if any other OS is returned
by `love.system.getOS()` it will use that string as-is.
* `version` (string/number) Version of the game running right now.
* `interval` (number) If specified, a check for the latest version will happen
again every `interval` seconds.
* `luajit_request` (string) luajit-request is checked for in `.` and `lib/.`, if
you have it elsewhere, specify its location here.
The following options are available, but generally should be left for itchy to
handle itself:
* `proxy` (string) An [HTTP proxy](https://github.com/Guard13007/insecure-proxy)
is used if luajit-request is unavailable, unless `proxy == false`. By default,
`https://104.236.139.220:16343` is used, which is running on a DigitalOcean
VPS I own. You can specify a different proxy here.
* `thread_channel` (string) itchy uses a channel named `itchy` for version
checking. You can call itchy's functions with different data tables and it
will use different threads & channels for each. You can also specify a channel
name here.