Yes, I am answering my own question.
After much digging and a talk with one of the best programmers I know, we have a solution, so I thought I would share it here. This solution takes the song name and artist, actually does make a call to the Link Maker API, gets back an XML document, and extracts the necessary info to create a link to the iTunes Store, opening the store to the song in an album by that artist that contains the song.
In the interface of the view controller, add:
@property (strong, readonly, nonatomic) NSOperationQueue* operationQueue;
@property (nonatomic) BOOL searching;
In the implementation:
@synthesize operationQueue = _operationQueue;
@synthesize searching = _searching;
Here are the methods and code that will do this for you:
// start an operation Queue if not started
-(NSOperationQueue*)operationQueue
{
if(_operationQueue == nil) {
_operationQueue = [NSOperationQueue new];
}
return _operationQueue;
}
// change searching state, and modify button and wait indicator (if you wish)
- (void)setSearching:(BOOL)searching
{
// this changes the view of the search button to a wait indicator while the search is perfomed
// In this case
_searching = searching;
dispatch_async(dispatch_get_main_queue(), ^{
if(searching) {
self.searchButton.enabled = NO;
[self.searchButton setTitle:@"" forState:UIControlStateNormal];
[self.activityIndicator startAnimating];
} else {
self.searchButton.enabled = YES;
[self.searchButton setTitle:@"Search" forState:UIControlStateNormal];
[self.activityIndicator stopAnimating];
}
});
}
// based on info from the iTunes affiliates docs
// http://www.apple.com/itunes/affiliates/resources/documentation/itunes-store-web-service-search-api.html
// this assume a search button to start the search.
- (IBAction)searchButtonTapped:(id)sender {
NSString* artistTerm = self.artistField.text; //the artist text.
NSString* songTerm = self.songField.text; //the song text
// they both need to be non-zero for this to work right.
if(artistTerm.length > 0 && songTerm.length > 0) {
// this creates the base of the Link Maker url call.
NSString* baseURLString = @"https://itunes.apple.com/search";
NSString* searchTerm = [NSString stringWithFormat:@"%@ %@", artistTerm, songTerm];
NSString* searchUrlString = [NSString stringWithFormat:@"%@?media=music&entity=song&term=%@&artistTerm=%@&songTerm=%@", baseURLString, searchTerm, artistTerm, songTerm];
// must change spaces to +
searchUrlString = [searchUrlString stringByReplacingOccurrencesOfString:@" " withString:@"+"];
//make it a URL
searchUrlString = [searchUrlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL* searchUrl = [NSURL URLWithString:searchUrlString];
NSLog(@"searchUrl: %@", searchUrl);
// start the Link Maker search
NSURLRequest* request = [NSURLRequest requestWithURL:searchUrl];
self.searching = YES;
[NSURLConnection sendAsynchronousRequest:request queue:self.operationQueue completionHandler:^(NSURLResponse* response, NSData* data, NSError* error) {
// we got an answer, now find the data.
self.searching = NO;
if(error != nil) {
NSLog(@"Error: %@", error);
} else {
NSError* jsonError = nil;
NSDictionary* dict = [NSJSONSerialization JSONObjectWithData:data options:0 error:&jsonError];
if(jsonError != nil) {
// do something with the error here
NSLog(@"JSON Error: %@", jsonError);
} else {
NSArray* resultsArray = dict[@"results"];
// it is possible to get no results. Handle that here
if(resultsArray.count == 0) {
NSLog(@"No results returned.");
} else {
// extract the needed info to pass to the iTunes store search
NSDictionary* trackDict = resultsArray[0];
NSString* trackViewUrlString = trackDict[@"trackViewUrl"];
if(trackViewUrlString.length == 0) {
NSLog(@"No trackViewUrl");
} else {
NSURL* trackViewUrl = [NSURL URLWithString:trackViewUrlString];
NSLog(@"trackViewURL:%@", trackViewUrl);
// dispatch the call to switch to the iTunes store with the proper search url
dispatch_async(dispatch_get_main_queue(), ^{
[[UIApplication sharedApplication] openURL:trackViewUrl];
});
}
}
}
}
}];
}
}
The XML file that comes back has a LOT of other good info you could extract here as well, including three sizes of album art, album name, cost, etc, etc.
I hope this helps someone else out. This stumped me for quite some time, and I thank a good friend of mine for making this work.
