Calling NSURLConnection one by one - ios

Question

I have a NSMutableArray containing 10 URLs from which I need to grab the HTTP headers.
Below is my code:
for(int i=0; i<[contactsArray count];i++)
{
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
NSString *reqstr=[NSString stringWithFormat:#"%#",urlString ];
[request setURL:[NSURL URLWithString:reqstr]];
NSLog(#"requested url is %#",reqstr);
[request setHTTPMethod:#"POST"];
[request setValue:#"application/json" forHTTPHeaderField:#"Accept"];
[request setValue:#"application/json" forHTTPHeaderField:#"content-type"];
[request setHTTPBody:[mDict JSONData]];
NSURLConnection *theConnection=[[NSURLConnection alloc]initWithRequest:request delegate:self startImmediately:YES];
}
current result: all requests are going to server at a time.
expected result: want to send one request to sever after getting response I want to send another request in background.
Any suggestions?

Answer 1

Refactor your code to use the sendAsynchronousRequest:queue:completionHandler: method, and call itself once the current post is complete:
Move your count to an instance variable. Let's call it currentItem. Your code might look something like this:
- (void) postItems;
{
while (currentItem < [contactsArray count)
{
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
NSString *reqstr=[NSString stringWithFormat:#"%#",urlString ];
[request setURL:[NSURL URLWithString:reqstr]];
NSLog(#"requested url is %#",reqstr);
[request setHTTPMethod:#"POST"];
[request setValue:#"application/json" forHTTPHeaderField:#"Accept"];
[request setValue:#"application/json" forHTTPHeaderField:#"content-type"];
[request setHTTPBody:[mDict JSONData]];
[NSURLConnection sendAsynchronousRequest: request
queue: dispatch_get_main_queue ()
completionHandler: ^(NSURLResponse *response, NSData *data, NSError *error)
{
//check for errors
//save any response data
//Now trigger the next request
currentItem++
[self postItems];
}
];
}
}
(The syntax for the completion block might not be exactly right. I struggle a little with the syntax for blocks that take parameters.)

Answer 2

You use ASIHTTPRequest asynchronous call:
Link for ASIHTTPRequest
Then write like following code:
for(int i=0; i<[contactsArray count];i++)
{
NSURL* url = [NSURL URLWithString:urlString];
__block ASIHTTPRequest* request = [ASIHTTPRequest requestWithURL:url];
[request setCompletionBlock:^
{
//NEED SOMEHOW RETURN TRUE IF SUCESSED
}];
[request setFailedBlock:^
{
//NEED RETURN FALSE
}];
[request startAsynchronous];
}