Question

I am using ASIHTTPRequest framework for making network calls in my iOS applications. But I don’t want to use it directly in all the controllers in my application. So I thought of writing a layer around ASIHTTPRequest. My code use this layer to use ASIHTTPRequest. The benefit wil be in future I should be able to replace this framework with some other framework and my code will be unchanged just the layer would change. I want to know what should be the strategy to do so. Should I subclass my class from ASIHTTPRequest class, or implement my own class. What should be the method I should consider implementing.

Currently I am implementing it like this.
My wrapper is

MyRequestHandler.h : NSObject       
@property ASIHTTPRequest *asiHttpReq;    

-(void) sendAsyncGetRequest
{
    self.asiRequest = [ASIHTTPRequest requestWithURL:self.url];
    if(self.tag != 0){
        self.asiRequest.tag = self.tag;
    }
    [self.asiRequest setDelegate:self];
    [self.asiRequest startAsynchronous];        
}

- (void)requestFinished:(ASIHTTPRequest *)request{
     MyResponseObj *respone = <From request obj>
     if([delegate respondsToSelector:@selector(requestFinished:)]){
            [delegate performSelector:@selector(requestFinished:) withObject:response];
        }
 }

And in my viewcontroller I would do this:

MyViewController.h : UIViewContoller
@property MyRequestHandler *reqHandler;

-(void) fireRequest
{
NSString* requestUrl = <create URL>;
if(requestUrl){

    // [self showLoadingIndicatorView];

    // Proceed for request.
    NSURL *url = [NSURL URLWithString:requestUrl];
    reqHandler = [MyRequestHandler requestWithURL:url];
    reqHandler.tag = 1000;
    [reqHandler setDelegate:self];
    [reqHandler sendAsyncGetRequest];
}
}

- (void)requestFinished:(MyResponse*) responseData{
        // Do Your parsing n all here.
}

- (void)requestFailed:(MyResponse*) responseData{
        // Handle the error here.
}

Is this the right way to do it. The problem here is as I have created property of myrequesthandler in viewcontroller I can only make one request at a time, and loosing the capability of ASIHTTPRequest of making multiple request simultaneously.

Can you suggest me how to approach problems like this.

Answer 1

This is what I’m using:

#import "ASIFormDataRequest.h"

@interface RequestPerformer : NSObject {
    id localCopy; // to avoid exec_bad_access with arc
    ASIHTTPRequest *getRequest;
    ASIFormDataRequest *postRequest;
}

@property (nonatomic, retain) id delegate;
@property (nonatomic, readwrite) SEL callback;
@property (nonatomic, readwrite) SEL errorCallback;

- (void)performGetRequestWithString:(NSString *)string stringDictionary:(NSDictionary *)stringDictionary delegate:(id)requestDelegate requestSelector:(SEL)requestSelector errorSelector:(SEL)errorSelector;
- (void)performPostRequestWithString:(NSString *)string stringDictionary:(NSDictionary *)stringDictionary dataDictionary:(NSDictionary *)dataDictionary delegate:(id)requestDelegate requestSelector:(SEL)requestSelector errorSelector:(SEL)errorSelector;

@end

//

#import "RequestPerformer.h"
#import "ASIHTTPRequest.h"
#import "ASIFormDataRequest.h"

@implementation RequestPerformer

@synthesize delegate;
@synthesize callback, errorCallback;

- (void)performGetRequestWithString:(NSString *)string stringDictionary:(NSDictionary *)stringDictionary delegate:(id)requestDelegate requestSelector:(SEL)requestSelector errorSelector:(SEL)errorSelector {

    localCopy = self;

    self.delegate = requestDelegate;
    self.callback = requestSelector;
    self.errorCallback = errorSelector;

    NSMutableString *requestStringData = [[NSMutableString alloc] init];
    if (stringDictionary)
        for (NSString *key in [stringDictionary allKeys])
            [requestStringData appendFormat:@"%@=%@&", key, [stringDictionary objectForKey:key]];
    NSString *resultString = [requestStringData substringToIndex:[requestStringData length]-1];

    getRequest = [[ASIFormDataRequest alloc] initWithURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@?%@", string, [resultString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]];
    [getRequest setDelegate:self];
    [getRequest setRequestMethod:@"GET"];

    //NSLog(@"request url = %@", [getRequest.url absoluteString]);
    [getRequest startAsynchronous];
}

- (void)performPostRequestWithString:(NSString *)string stringDictionary:(NSDictionary *)stringDictionary dataDictionary:(NSDictionary *)dataDictionary delegate:(id)requestDelegate requestSelector:(SEL)requestSelector errorSelector:(SEL)errorSelector {

    localCopy = self;

    self.delegate = requestDelegate;
    self.callback = requestSelector;
    self.errorCallback = errorSelector;

    NSURL *url = [NSURL URLWithString:string];

    postRequest = [[ASIFormDataRequest alloc] initWithURL:url];
    [postRequest setDelegate:self];
    [postRequest setRequestMethod:@"POST"];

    if (stringDictionary)
        for (NSString *key in [stringDictionary allKeys])
            [postRequest setPostValue:[stringDictionary objectForKey:key] forKey:key];

    if (dataDictionary)
        for (NSString *key in [dataDictionary allKeys])
            [postRequest setData:[dataDictionary objectForKey:key] forKey:key];

    //NSLog(@"request url = %@", [postRequest.url absoluteString]);
    [postRequest startAsynchronous];
}

#pragma mark - ASIHTTPRequest Delegate Implementation

- (void)requestFinished:(ASIHTTPRequest *)crequest {
    NSString *status = [crequest responseString];

    if (self.delegate && self.callback) {
        if([self.delegate respondsToSelector:self.callback])
            [self.delegate performSelectorOnMainThread:self.callback withObject:status waitUntilDone:YES];
        else
            NSLog(@"No response from delegate");
    }
    localCopy = nil;
}
- (void)requestFailed:(ASIHTTPRequest *)crequest {
    if (self.delegate && self.errorCallback) {
        if([self.delegate respondsToSelector:self.errorCallback])
            [self.delegate performSelectorOnMainThread:self.errorCallback withObject:crequest.error waitUntilDone:YES];
        else
            NSLog(@"No response from delegate");
    }
    localCopy = nil;
}

@end

To use it, just import RequestPerformer.h in your UIViewController and do smth like:

[requestManager performGetRequestWithString:tempString stringDictionary:stringDictionary dataDictionary:dataDictionary delegate:self requestSelector:@selector(requestSucceeded:) errorSelector:@selector(requestFailed:)];

Parameters:

• (NSString *)string – url string, where to post your request;
• (NSDictionary *)stringDictionary – dictionary, which contains all the
  text information (such as name, id etc.);
• (NSDictionary *)dataDictionary – dictionary, which contains all data information (such as photos, files, etc.);
• (id)requestDelegate – delegate to perform selectors below;
• (SEL)requestSelector – selector, which will be executed while successfully request;
• (SEL)errorSelector – selector, which will be executed, while error occurred.