Parse the Hackage upload log and write the latest version of each package into a JSON/JSONP file.
Up-to-date versions of both JSON and JSONP are repeatedly generated at
http://www.typeful.net/~tbot/hackage/. The JSONP callback is hard-coded to
hackagePackageVersionsCallback.
import Data.Maybe
import qualified Data.Map as Map
import Network.URI
import Network.HTTP
import Data.Aeson.Generic
url :: String
url = "http://www.typeful.net/~tbot/hackage/latest-package-versions.json"
-- | Return latest version of a package.
--
-- >>> getVersion "hspec"
-- Just "0.9.2"
getVersion :: String -> IO (Maybe String)
getVersion name = do
r <- simpleHTTP request >>= getResponseBody
return (decode r >>= Map.lookup name)
where
request = (mkRequest GET . fromJust . parseURI) urlJSONP allows a javascript client to relax the same origin policy and retrieve
the above JSON by providing the callback function
hackagePackageVersionsCallback.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Example</title>
</head>
<body>
<p>
The latest version of hspec is <span id="result">???</span>.
</p>
<script src="http://code.jquery.com/jquery-1.7.2.min.js"></script>
<script src="custom.js"></script>
</body>
</html>$(document).ready(function() {
/* fetch latest packages versions, the result will be passed to
* hackagePackageVersionsCallback(..) */
$.getScript("http://www.typeful.net/~tbot/hackage/latest-package-versions.jsonp");
});
function hackagePackageVersionsCallback(response) {
/* output latest version of hspec */
var version = $(response).attr("hspec");
$("#result").text(version);
}