Passing param in URL to get json back in IOS - json

Question

Sorry i am really beginner in IPhone development,i am pulling json data from URL and its pulling and loading data perfectly in UITableView, below is code
- (void)fetchFeed
{
NSString *requestString = #"http://bookapi.bignerdranch.com/courses.json";
NSURL *url = [NSURL URLWithString:requestString];
NSURLRequest *req = [NSURLRequest requestWithURL:url];
self.session = [NSURLSession sharedSession];
NSURLSessionDataTask *dataTask =
[self.session dataTaskWithRequest:req
completionHandler:
^(NSData *data, NSURLResponse *response, NSError *error) {
NSDictionary *jsonObject = [NSJSONSerialization JSONObjectWithData:data
options:0
error:nil];
self.courses = jsonObject[#"courses"];
dispatch_async(dispatch_get_main_queue(), ^{
[self.tableView reloadData];
});
}];
[dataTask resume];
}
Now i want to add filter by instructors, Can any one tell me how i can do that.
Thanks

Answer 1

GET
GET request is just a matter of appending query strings to the API url, for example:
NSString *format = [NSString stringWithFormat:#"http://www.yourapiurl.com?id=%#","123";
NSURL *url = [NSURL URLWithString:format];
NSLog(#"%#",url);
//Creating the data object that will hold the content of the URL
NSData *jsonData = [NSData dataWithContentsOfURL:url];
NSError *error = nil;
NSDictionary *result = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&error];
POST
-(NSData *)post:(NSString *)postParams{
//Build the Request
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:#"http://www.yourapiurl.com"]];
[request setHTTPMethod:#"POST"];
[request setValue:[NSString stringWithFormat:#"%lu", (unsigned long)[postParams length]] forHTTPHeaderField:#"Content-length"];
[request setHTTPBody:[postParams dataUsingEncoding:NSUTF8StringEncoding]];
//Send the Request
NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse: nil error: nil];
//Get the Result of Request
NSString *response = [[NSString alloc] initWithBytes:[returnData bytes] length:[returnData length] encoding:NSUTF8StringEncoding];
return returnData;
}
usage:
NSString *postString = [NSString stringWithFormat:#"prop1=%#&prop2=%#&prop3=%#",
"value1","value2","value3"];
NSData *JsonData = [self post :postString];
NSDictionary *result = [NSJSONSerialization JSONObjectWithData:JsonData options:NSJSONReadingMutableContainers error:nil];
//then parse the JSON