Display a local public transport route by using the Wiener Linien API

The core problem of this challenge is the proper formulation (encoding) of the request and the correct interpretation (decoding) of the server-response. Another problem is the sending and the receiving of the XML-files with a server-side scripting language such as PHP.
1 answer

Wiener Linien API

The challenge was to get a public transport route, by sending time, date, start and destination address. The problem was solved by using the "Wiener Linien API" (http://akirk.github.com/Wiener-Linien-API/). The PHP-Code sends a XML-request with all details of the appointment and get a XML-respond with the transport connection.

For building a request the PHP-function "buildRequest()" can be used.
The following example illustrates a query from "Seckendorfstrasse 4" to "Wiedner Hauptstr. 8":

$params = array();
$params["outputCoords"] = "WGS84";
$params["from"] = "Seckendorfstrasse 4";
$params["to"] = "Wiedner Hauptstr. 8";
$params["year"] = "2011";
$params["month"] = "12";
$params["day"] = "14";
$params["hour"] = "17";
$params["minute"] = "00";
$params["deparr"] = "arr";
$params["modality"] = "pt";
$params["sourceFrom"] = "gps";
$params["sourceTo"] = "stoplist";
$req = buildRequest("api_get_route", $params);

Afterwards, the XML-request must be sent to the following webservice: http://webservice.qando.at/2.0/webservice.ft.

$response = httpPost("http://webservice.qando.at/2.0/webservice.ft", $req);

Finally, the XML-response must be load into a Document Object Model (DOM). A DOM presents an XML document as a tree-structure, which makes it easy to interpret and evaluate the local public transport route.

$dom = new DOMDocument();
$dom->formatOutput = true;
$dom->preserveWhiteSpace = false;

The complete DOMDocument manual is available on the website: http://php.net/manual/de/class.domdocument.php.

To print out the XML-response of the public transport route, use the following PHP-code:

echo "Response: " .$dom->saveXML(). "";