Cannot read XML File

Question

Hi there,

got a little problem with receiving the contents of a xml file (using TouchXML).

My first query works very well, looks something like this:

NSString *url = [NSString stringWithFormat:STATION_ID, latitude, longtitude];
CXMLDocument *rssParser = [[CXMLDocument alloc] initWithContentsOfURL:[NSURL URLWithString:url] options:0 error:nil];
NSLog(@"%@",rssParser);

so this log gives me the complete XML file.

after that, in another method im trying the same:

NSString *url = [NSString stringWithFormat:WEATHER_URL, [positionInformation objectForKey:@"stationId"]];
CXMLDocument *rssParser = [[CXMLDocument alloc] initWithContentsOfURL:[NSURL URLWithString:url] options:0 error:nil];
NSLog(@"%@", rssParser);

but the log im getting is (null). Loggin the URL String gives me the right URL without spaces or something, the URL Log for example looks like this:

NSString *url = [NSString stringWithFormat:WEATHER_URL, [positionInformation objectForKey:@"stationId"]];
NSLog(@"%@", url);

The result in the debugger Console is

http://api.wunderground.com/weatherstation/WXCurrentObXML.asp?ID=KCASUNNY19

looking at this file with my browser seems to be ok. Anybody know whats going wrong?????

I also tried, first to get the content of this URL by stringWithContentsOfURL, but this also not worked.

Answer 1

You should try using the error argument of initWithContentsOfURL:options:error:. Create an NSerror *object, and pass it in thusly:

NSError      *error;
CXMLDocument *rssParser = [[CXMLDocument alloc] initWithContentsOfURL:[NSURL URLWithString:url] options:0 error: &error];

If you don't get an rssParser object, check that error.

Answer 2

i copied the content of this xml file to my own server and changed the url path. this works correcty, so i think there is a problem with reading this ".asp" file.

hmm. but its XML content, strange.

//edit: i made a little php file on my server that returns the content of the "asp" file:

<?php
  echo file_get_contents("http://api.wunderground.com/weatherstation/WXCurrentObXML.asp?ID=KCASANFR70");
 ?>

reading the contents of my script works, but this workaround is not what i want.

oh damn =/

Answer 3

Are you sure that your URL string is properly encoded, so that the question mark gets interpreted as a query? You might want to look at using dataUsingEncoding or stringUsingEncoding on your URL before using it to initialize rssReader.

Answer 4

This guy was having the same problem: http://www.iphonedevsdk.com/forum/iphone-sdk-development/15963-problem-initwithcontentsofurl.html. Looks like the API at Weather Underground is expecting a user-agent and returning a 500 HTTP response when it doesn't see one. You can use -initWithData:options:error: on CXMLDocument to pass the data you get using NSMutableURLRequest.