Hi all,
Almost every mobile app uses REST API where user needs to handle web requests.
The request could be GET or POST
The data to be carried could be JSON or XML or nay other.
So today we will be working on GET and POST requests using JSON.
Hope you find it useful and easy too.
:)
Lets begin...
***********************How things work******************************
LoginViewController
- Implements the Webservice Protocol.
- Calls method of webserviceManager to execute login webrequest
- Handles response
WebServiceManager
- Creates JSON request dict / object.
- Makes GET / POST request.
- Creates NSURL Connections.
- Receives the Response.
- Using delegate makes a callback to the calling class that implemented the protocol method.
***************************************************************************
1) Create WebServiceManager.h
- @property (weak, nonatomic) id delegate;
- @property (strong, nonatomic) NSMutableData *responseData;
- @property (strong, nonatomic) NSURLConnection *remoteConnection;
- @property (nonatomic) NSInteger statusCode;
- @property (strong, nonatomic) NSMutableData *connectionData;
- @property (nonatomic) WebServiceTransactionType transactionType;
- Create ENUMS
This protocol will be implemented by the class that implements it
typedef NS_ENUM (NSInteger, WebServiceTransactionType)
{
WebServiceTransactionTypeUserLogin,
WebServiceTransactionTypeUserLogout,
};
typedef NS_ENUM (NSInteger, NetworkOperationStatusCode)
{
NetworkOperationStatusCodeUnkown,
NetworkOperationStatusCodeInProgress,
NetworkOperationStatusCodeSuccess,
NetworkOperationStatusCodeError
};
#pragma mark - Delegate Protocol
@protocol WebServiceTransactionResponseDelegate <NSObject>
@required
- (void)assitant : (WebServicesManager *)assistant
transaction : (WebServiceTransactionType)type
status : (NetworkOperationStatusCode)statusCode
remoteData : (id)remoteData;
@end
3) WebServiceManager.m
a) Execute login with POST request & credentials in JSON format.
Call this method from any class
- (void)authenticateLoginforUserName : (NSString*)userName
password : (NSString*)password
transactiontype : (WebServiceTransactionType)transaction_type
delegate : (id)del
{
self.delegate = del;
NSDictionary *requestDict = [[NSDictionary alloc] initWithObjectsAndKeys:
userName ,@"userName",
password ,@"password",
nil];
NSString *url = [NSString stringWithFormat:@"%@%@",BASE_URL,LOGIN_REQUEST];
[self createURLRequest : url
requestDict : requestDict
transactionType : transaction_type
delegate : del];
}
b) Creating a generic method that handles GET / POST request
- (void)createURLRequest : (NSString*)url
requestDict : (NSDictionary*)requestDict
transactionType : (WebServiceTransactionType)transaction_type
delegate : (id)del
{
if (self.remoteConnection)
[self.remoteConnection cancel];
self.delegate = del;
self.transactionType = transaction_type;
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:
[NSURL URLWithString : url]];
[request setValue : @"application/json" forHTTPHeaderField : @"Content-Type"];
if(requestDict != nil)
{
[request setHTTPMethod:@"POST"];
NSData *jsonData = [NSJSONSerialization dataWithJSONObject : requestDict
options : 0
error : nil];
[request setHTTPBody : jsonData];
}
else
[request setHTTPMethod : @"GET"];
[request setTimeoutInterval : 10];
self.remoteConnection = [NSURLConnection connectionWithRequest : request
delegate : self];
self.statusCode = -1;
[self.remoteConnection start];
}
c) NSURLConnection Delegate methods
- (void)connection : (NSURLConnection *)connection
didFailWithError : (NSError *)error
{
if([self.delegate respondsToSelector:@selector(assitant : transaction : status : remoteData : )])
{
[self.delegate assitant : self
transaction : self.transactionType
status : NetworkOperationStatusCodeError
remoteData : nil];
}
if (connection == self.remoteConnection)
self.remoteConnection = nil;
}
- (void)connection : (NSURLConnection *)connection
didReceiveResponse : (NSURLResponse *)response
{
self.statusCode = [(NSHTTPURLResponse*) response statusCode];
if (self.statusCode > 200) return;
self.connectionData = nil;
}
- (void)connection : (NSURLConnection *)connection
didReceiveData : (NSData *)data
{
if (self.statusCode > 200 || data == nil) return;
if (self.connectionData == nil)
self.connectionData = [NSMutableData dataWithData:data];
else
[self.connectionData appendData : data];
}
- (void)connectionDidFinishLoading : (NSURLConnection *)connection
{
id temp;
if (self.statusCode > 200)
{
temp = nil;
if([self.delegate respondsToSelector : @selector(assitant : transaction : status : remoteData : )])
{
[self.delegate assitant : self
transaction : self.transactionType
status : NetworkOperationStatusCodeError
remoteData : nil];
}
}
else
{
if (connection == self.remoteConnection)
self.remoteConnection = nil;
if(self.statusCode == 200)
{
if([self.delegate respondsToSelector:@selector(assitant : transaction : status : remoteData :)])
{
NSDictionary *parsedData = [Utils convertJSONDataToDictionary : self.connectionData];
// Check JSON Parsing in another blog of mine : JSON Parsing Tutorial
[self.delegate assitant : self
transaction : self.transactionType
status : NetworkOperationStatusCodeSuccess
remoteData : parsedData];
}
}
}
}
4) Implementing the protocol in LoginViewController.h
@interface LoginViewController : UIViewController
<WebServiceTransactionResponseDelegate>
@end
5) Calling WebServiceManager from LoginViewController.m
WebServicesManager *webManager = [[WebServicesManager alloc] init];
[webManager authenticateLoginforUserName : @"Swati"
password : @"password"
transactiontype : WebServiceTransactionTypeUserLogin
delegate : self];
6) Handling response in LoginViewController.m
- (void) assitant : (WebServicesManager *)assistant
transaction : (WebServiceTransactionType)type
status : (NetworkOperationStatusCode)statusCode
remoteData : (id)remoteData
{
switch (type)
{
case WebServiceTransactionTypeUserLogin:
{
if(statusCode == NetworkOperationStatusCodeError)
{
// FAILURE
return;
}
else
{
// SUCCESS
}
}
break;
default:
break;
}
}
tada........
now try out yourself.....
