CODEWITHSUNDEEP
iosobjective-casynchronous
user5513630
user5513630

Reputation: 1699

Change from synchronous to Asynchronous

Here i use GET method to fetch data from one Url and display the data in table view.I used synchronous to get data to display.

Needed:

I need to change this code to Asynchronous to display same data in table view.Here i just use my console to display data.

Here my code:

#import "ViewController.h"
#import <CommonCrypto/CommonDigest.h>
@interface ViewController ()
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];

    [self getdata];
}

-(NSString*)sha256HashFor:(NSString*)input
{
    const char* str = [input UTF8String];
    unsigned char result[CC_SHA256_DIGEST_LENGTH];
    CC_SHA256(str, strlen(str), result);

    NSMutableString *ret = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH*2];
    for(int i = 0; i<CC_SHA256_DIGEST_LENGTH; i++)
    {
        [ret appendFormat:@"%02x",result[i]];
    }
    return ret;
}

-(void)getdata {

    NSString *userName = @"[email protected]";
    NSString *password = @"passer";
    //encoding
    NSData *Data = [password dataUsingEncoding:NSUTF8StringEncoding];
    NSString *base64String = [Data base64EncodedStringWithOptions:0];

    base64String=[self sha256HashFor: base64String];

    NSString *urlString = @"https://api.exampleurl/user23/doc";

    NSMutableURLRequest *request= [[NSMutableURLRequest alloc] init];
    [request setURL:[NSURL URLWithString:urlString]];
    [request setHTTPMethod:@"GET"];

    NSString *authStr = [NSString stringWithFormat:@"%@:%@", userName, base64String];
    NSData *authData = [authStr dataUsingEncoding:NSUTF8StringEncoding];

    NSString *authValue = [NSString stringWithFormat:@"Basic %@", [authData base64EncodedStringWithOptions:0]];
    [request setValue:authValue forHTTPHeaderField:@"Authorization"];
    NSData *returnData = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
    NSString *str = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
    NSLog(@"%@", str);

  }

Upvotes: 0

Views: 98

Answers (1)

Amit
Amit

Reputation: 283

For making Asynchronous http request you can use : 

[NSURLConnection sendAsynchronousRequest:httpRequest queue:[AppDelegate connectionQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
{
    ....
}];

or you can implement NSURLConnectionDataDelegate protocol

Updated Answer :

  1. First create a connection queue in app delegate file

    + (NSOperationQueue *)connectionQueue { dispatch_once(&once, ^{ connectionQueue = [[NSOperationQueue alloc] init]; [connectionQueue setMaxConcurrentOperationCount:2]; [connectionQueue setName:@"com.XYZ.connectionqueue"]; }); return connectionQueue; }

Here is updated getData Method :

-(void)getdata {

NSString *userName = @"[email protected]";
NSString *password = @"passer";
//encoding
NSData *Data = [password dataUsingEncoding:NSUTF8StringEncoding];
NSString *base64String = [Data base64EncodedStringWithOptions:0];

base64String=[self sha256HashFor: base64String];

NSString *urlString = @"https://api.exampleurl/user23/doc";

NSMutableURLRequest *request= [[NSMutableURLRequest alloc] init];
[request setURL:[NSURL URLWithString:urlString]];
[request setHTTPMethod:@"GET"];

NSString *authStr = [NSString stringWithFormat:@"%@:%@", userName, base64String];
NSData *authData = [authStr dataUsingEncoding:NSUTF8StringEncoding];

NSString *authValue = [NSString stringWithFormat:@"Basic %@", [authData base64EncodedStringWithOptions:0]];
[request setValue:authValue forHTTPHeaderField:@"Authorization"];

__block NSString *str;

 [NSURLConnection sendAsynchronousRequest:httpRequest queue:[AppDelegate connectionQueue]completionHandler:^(NSURLResponse *response, NSData *data, NSError *error){
str = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];}];
NSLog(@"%@", str);

}

Upvotes: 3

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