In making this website, I wanted to put on my homepage my Google Latitude determined current location (at the statewide level). Google provides the Latitude API, but this is only for authenticated users, and therefore cannot be used by people wishing to publicly publish their location.
The Latitude website provides a location widget that can be placed on your website to show your current location, but it uses an undocumented API. After a bit of effort reverse engineering the location widget, I eventually came up with the following URL:
http://www.google.com/latitude/apps/badge/api?user=4048757213362106746&type=json
This is an undocumented API by Google, and notably cannot use JSONP. That means that I couldn’t use that URL directly from within my static-page Jekyll-generated website thanks to the same origin policy.
In order to work around this rather severe limitation, I leveraged the power of YQL, which is able to effectively turn a JSON-only data source into a JSONP data source. At the end of the day, I’m able to retrieve my current location from Latitude by going through Yahoo with the following code:
function doLatitude( id, elem ) {
var url = "http://www.google.com/latitude/apps/badge/api";
var data = $.param({
user: id,
type: "json"
});
var full_url = url + "?" + data;
$.ajax({
url: "http://query.yahooapis.com/v1/public/yql",
dataType: "jsonp",
data: {
q: "SELECT * FROM json WHERE url='" + full_url + "'",
format: "json"
},
success: function( data ) {
if( data.query.results.json.features == null ) {
elem.html("<span style=\"font-style:italic\">location unavailable</span>");
} else {
elem.html(data.query.results.json.features.properties.reverseGeocode);
}
},
error: function( _, textStatus, errorThrown ) {
elem.replaceWith(textStatus + ": " + errorThrown);
}
});
}