Re: no subject

[Richard Frith-Macdonald]

On 14 Apr 2008, at 11:56, Richard Frith-Macdonald wrote:

> On 14 Apr 2008, at 10:41, Sebastian Reitenbach wrote:
>
> > Hi,
> >
> > I tried to download a csv file from a webserver.I found an example  
> > using
> > NSURL.
> > As the documentation says, NSURL needs an
> > escaped string, so I used
> > stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding, so  
> > I wrote
> > the test below:
> > =================Sample Program================================
> > #include <Foundation/Foundation.h>
> >
> > int
> > main(int argc, const char *argv[])
> > {
> > id pool = [[NSAutoreleasePool alloc] init];
> >
> > NSString *GKey =
> > @"ABQIAAAAvp3__HwvT3VkixIIbsW0axQuKI_6t1bH2P0vCI_Q8jfpn8qdNBQMnneljxh9czilkau_bYSCXteS_A 
> > ";
> >
> >
> >
> > NSString *Address = @"Potsdamer+Platz+Berlin+Germany";
> > NSString *URLString = [NSString
> > stringWithFormat:@"http://maps.google.com/maps/geo?q= 
> > %@&output=csv&key=%@",
> > Address, GKey];
> > URLString = [URLString
> > stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
>
> That last line is wrong ... the method is for fixing strings which  
> are not legal as parts of a URL so that they can be used within a  
> URL ... if you apply the method to en entire URL, what you get is  
> obviously not a URL, but rather a string containing characters which  
> are legal to put inside a URL.
> While the first sentence of the GNUstep documentation for the method  
> is perhaps unclear (I've tried to clarify it), the remainder of the  
> documentation goes on to explain exactly what the method does.  It  
> also warns that, where you are filling in form fields (as in the  
> example above), you need to perform additional escaping for '+','='  
> and '&' because the implementation does not do that for you (to  
> maintain macos compatibility).


Something like the following function might be what you want for  
handling form data:

NSString*
URLFormField(NSString *value)
{
  static NSCharacterSet *illegtal = nil;
  NSRange r;

  if (illegal == nil)
    {
      illegal = [[NSCharacterSet characterSetWithCharactersInString:  
@"+=&"] retain];
    }
  value = [value stringByAddingPercentEscapesUsingEncoding:  
NSUTF8StringEncoding];
  r = [value rangeOfCharacterFromSet: illegal];
  if (r.length > 0)
    {
      NSMutableString *m = [value mutableCopy];

      while (r.length > 0)
        {
          switch ([m characterAtIndex: r.location])
            {
	      case '+': [m replaceCharactersInRange: r withString: @"%2B"];  
break;
	      case '=': [m replaceCharactersInRange: r withString: @"%3D"];  
break;
	      default: [m replaceCharactersInRange: r withString: @"%26"];  
break;
            }
          r = [m rangeOfCharacterFromSet: illegal];
       }
      value = [m autorelease];
    }
  return value;
}