Objective-C: Parsing a non-xml website - iphone

Question

I'd like to develop a very simple "bus timetable" app that loads a particular URL and can use the HTML to figure out bus numbers, their routes and expected times. Unfortunately it's a very simple website, so the data is spread across TD and DIV fields, rather than in xml.
Can anyone provide some pointers on where to start? I've had a look at NSURL, NSURLConnection and the like, and am able to download the contents of an HTML file, but I'm unsure what to do next.
Many thanks.

Answer 1

There are many ways to accomplish this task. Ultimately, you will want to retrieve something an easily-processed format other than raw html. Here is one way to do it:
I would recommend writing a server-side script that converts the html into an easily-digestible format, such as JSON.
If you have php experience, you write a script / web-service that grabs the needed elements and place the content in an associative array. Place the script on your server and have your application call the web-service URL when ready to retrieve the info.
Finally, return the information as a JSON object and parse the JSON into your app.
<?php
//parse html into the $array variable.
$array = json_encode($array);
echo $array;
?>
I would recommend using the SBJSON library for parsing the JSON object: Take a look at SBJSON
Initiate your NSURL request by calling the script URL.
NSURLRequest *request =[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.yoursite/script.php"]];
If the request is successful, parse the resulting JSON: (assuming use of SBJSON library)
-(void)connectionDidFinishLoading:(NSURLConnection *)connection {
[connection release];
NSString *responseString = [[NSString alloc] initWithData: responseData encoding: NSUTF8StringEncoding];
[responseData release];
NSError *error;
SBJSON *json = [[[SBJSON alloc] init]autorelease];
NSDictionary *busData = [json objectWithString:responseString error: &error];
//busData contains bus data that you formatted...
Beware, this is assuming that you want to add your data to a dictionary and then display it appropriately. I consider this a mere snippet for formatting data in a way you desire. Parsing all of the html within the app may difficult and that is why I advocate formatting the data as JSON first. If you decide to go the XML route, there are several XML parsers as well.