MJGHTTPRequest

Introduction

MJGHTTPRequest is a class designed to be subclassed to take the pain out of performing HTTP requests on iOS. Most HTTP APIs have a base URL that's the same (e.g. api.twitter.com) and take certain parameters. They also usually return a given format of data such as JSON or XML. MJGHTTPRequest enables you to create your own class to talk to these APIs and handle all the HTTP level things for you. All you need to do is hook into whatever mechanism you want to handle the returned data which might be passing it through a JSON or XML deserialiser for example.

Features

• GET & POST HTTP requests.
• URL encoded, multipart & raw POST formats.
• Customisation hooks to act on the request at its various stages.

Why should I use MJGHTTPRequest?

MJGHTTPRequest is useful for when you have a project that is using an HTTP API and you find yourself writing the same code over and over again. Whether it's the same code using standard Cocoa APIs or some other asynchronous HTTP request framework, MJGHTTPRequest is the perfect replacement to take the pain out of all that duplicated code. It gives you the flexibility to write once a class that conforms to the spec laid out by your HTTP API and then use it everywhere!

License

MJGHTTPRequest uses the 2-clause BSD license. So you should be free to use it pretty much however you want. Contact me if you require further information.

Copyright (c) 2011 Matt Galloway. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Automatic Reference Counting (ARC)

This project uses ARC.

Author

MJGHTTPRequest is written and maintained by Matt Galloway http://iphone.galloway.me.uk.

Projects using MJGHTTPRequest

• BeerMap - http://www.beermap.co/
• Kindmags Magazine Framework - http://www.kindmags.com/

Are you using MJGHTTPRequest? If so, contact me and I'll add you to the list.

How to use

As an example, we will assume there is a HTTP API which is based at http://api.example.com/v1/ which has the following methods:

• search - takes a single paramter term and returns an array of results. Result will be found in under the key results in the returned object.
• upload - takes files to be uploaded to the server and returns success or failure.

In addition, all methods are required to have a format paremeter set in the query part of the URL to indicate either json or xml return types. We will use json. The API defines that every request will return a JSON object with the data in it.

Adding MJGHTTPRequest to your project

All you need to do to get started is to add everything in the Source folder to your project.

Subclassing MJGHTTPRequest

1. Create a class which inherits from MJGHTTPRequest:

   #import "MJGHTTPRequest.h"
   @interface MyApiRequest : MJGHTTPRequest
   @property (nonatomic, strong) NSString *path;
   @end
   

2. Implement the required methods:

   @implementation MyApiRequest
   
   @synthesize path;
   
   - (NSString*)url {
       return [NSString stringWithFormat:@"http://api.example.com/v1/%@", path];
   }
   
   - (NSDictionary*)extraParameters {
       return nil;
   }
   
   - (NSDictionary*)extraGetParameters {
       return [NSDictionary dictionaryWithObjectsAndKeys:
               @"json", @"format",
               nil];
   }
   
   - (id)handleResult:(NSData*)result error:(NSError**)error {
       // We know our API is returning a JSON object, so lets deserialise it and return the object
       
       NSError *jsonError = nil;
       NSDictionary *outResult = [NSJSONSerialization JSONObjectWithData:result 
                                                                 options:0 
                                                                   error:&jsonError];
       if (jsonError) {
           if (error) {
               *error = jsonError;
           }
           return nil;
       }
       
       return outResult;
   }
   @end
   

Using your subclass

1. Now use the subclass to peform a search:

   MyApiRequest *request = [[MyApiRequest alloc] initWithRequestMethod:MJGHTTPRequestMethodGET];
   request.path = @"search";
   request.parameters = [NSDictionary dictionaryWithObjectsAndKeys:@"bunnies", @"term", nil];
   [request startWithHandler:^(id result, NSHTTPURLResponse *response, NSError *error){
       if (!error) {
           // Yay the request worked!
           NSArray *results = [(NSDictionary*)result objectForKey:@"results"];
           NSLog(@"Results:\n%@", results);
       } else {
           // Ooops! Error!
       }
   }];
   

2. And now upload a picture:

   UIImage *image = <UIImage_from_somewhere>;
   MyApiRequest *request = [[MyApiRequest alloc] initWithRequestMethod:MJGHTTPRequestMethodPOST];
   request.postMethod = MJGHTTPRequestPOSTMethodFormData;
   request.path = @"upload";
   [request addFileData:UIImagePNGRepresentation(image) 
                 forKey:@"image" 
           withFilename:@"image.png" 
                   type:@"image/png"];
   [request startWithHandler:^(id result, NSHTTPURLResponse *response, NSError *error){
       if (!error) {
           // Yay the request worked!
       } else {
           // Ooops! Error!
       }
   }];