RSNetworking – Major Update

I recently wrote an iOS communication library for the SparkCore in Objective-C and it gave me some great ideas on how the RSNetworking library could work.  I have updated the RSNetworking library to include my ideas and will be depreciating the original RSNetworking class soon.  After trying the new library out with the sample project, I am really excited about the update.  Please let me know what you think of the changes and any ideas that you may have.  You can find the code, with a sample application on GitHub here:  https://github.com/hoffmanjon/RSNetworking

While the original RSNetworking class is still in the library, I have put notes in the class that it will be going away soon.  Instead I moved the dataFromURL, stringFromURL, dictionaryFromURL, and imageFromURL functions to the new RSURLRequest class.  You can use these functions exactly like you used them before.  Eventually I would like to make these functions class (static) functions but it does not appear that the class (static) functionally is fully implemented yet (as of beta 4) since I cannot define class variables yet.

The isHostnameReachable function has moved to the RSUtilities class.  The RSUtilities class will contain various utilities.  Currently the isHostnameReachable function is the only function defined in the RSUtilities class.

Now we come to the big changes in the library.  These changes are part of two classes.  These are the RSTransaction and RSTransactionRequest classes.  Lets look at how we would use them to submit a GET request to Apple’s iTunes search API:

//initilate the RSTransactionRequest()

        var rsRequest = RSTransactionRequest()

       

//Define a RSTranaction object

        var rsTransGet = RSTransaction(transactionType: RSTransactionType.GET, baseURL: "https://itunes.apple.com", path: "search", parameters: ["term":"jimmy+buffett","media":"music"])

       

   

//Call the dictionaryFromRSTransaction function to make the request to the iTunes search API using the RSTransaction we created

        rsRequest.dictionaryFromRSTransaction(rsTransGet, completionHandler: {(response : NSURLResponse!, responseDictionary: NSDictionary!, error: NSError!) -> Void in

            if !error? {

                     println(responseDictionary)

            } else {

                //If there was an error, log it

                println("Error : \(error)")

            }

            })

We begin by initializing a RSTransactionRequest object.  Eventually I would like to make the functions in RSTransactionRequest class (static) functions but, like I noted above, the class (static) functionality does not look complete yet. 

Once we have the RSTransactionRequest object, we then create an RSTransaction object using the init(transactionType: RSTransactionType, baseURL: String,  path: String, parameters: [String: String]) initializer.  The RSTransaction class is designed to contain everything needed to create a request to a HTTP web service.  We then use the dictionaryFromRSTransaction function from the RSTransactionRequest object, passing in the RSTransaction object, to make the web service call.

What makes this so nice is we can now simply update the parameters of the RSTransaction class like this:

rsTransGet.parameters = ["term":"jimmy","media":"music"]

Then we can resubmit the RSTransaction to make another call. This will allow use to have numerous web services configured but we will only need one instance of the RSTransactionRequest class.  This will really become evident when we can make the functions in the RSTransactionRequest class, class (static) functions.

Lets take a look at how we would submit a POST request using the posttestserver.com site.  To make this request we use the same RSTransactionRequest object (rsRequest) that we used to make the GET request to Apple’s iTunes search API.  Here is the code:

//Post request

var rsTransPost = RSTransaction(transactionType: RSTransactionType.POST, baseURL: "https://posttestserver.com", path: "post.php", parameters: ["key":"value","key2":"value2"])

       

//Call the stringFromRSTrasaction function to make the request to posttestserver.com

rsRequest.stringFromRSTransaction(rsTransPost, completionHandler: {(response : NSURLResponse!, responseString: NSString!, error: NSError!) -> Void in

        if !error? {

            //Log response string

            println(responseString)

        } else {

            //If there was an error, log it

            println("Error : \(error)")

        }

       })

As you can see, the POST requests is exactly like the GET requests except we changed the transactionType parameter to RSTransactionType.POST instead of RSTransactionType.GET.

The RSTransaction class exposes four properties, one initiator and one method.  These are:

- Properties

* TransactionType - This defines the HTTP request method.  Currently there are three types, GET, POST, UNKNOWN.  Only the GET and POST actually sends a request.

* baseURL - This is the base URL to use for the request.  This will normally look something like this:  "https://itunes.apple.com".  If you are going to a non-standard port you would put that here as well.  It would look something like this:  "http://mytestserver:8080"

*path - The path that will be added to the base url.  This will normally be something like this: "search".  It can also include a longer path string like: "path/to/my/service"

* parameters - Any parameters to send to the service.

- Initiators

* init(transactionType: RSTransactionType, baseURL: String,  path: String, parameters: [String: String]) - This will initialize the RSTransaction with all properties needed.

- Function

* getFullURLString() -> String - Builds and returns the full URL needed to connect to the service.

The RSTransactionRequest contains exposes four functions.  These are:

* dataFromRSTransaction(transaction: RSTransaction, completionHandler handler: RSNetworking.dataFromRSTransactionCompletionCompletionClosure):

 Retrieves an NSData object from the service defined by the RSTransaction.  This is the main function and is used by the other three functions to retrieve an NSData object prior to converting it to the required format.

* stringFromRSTransaction(transaction: RSTransaction, completionHandler handler:  RSNetworking.stringFromRSTransactionCompletionCompletionClosure):  

Retrieves an NSString object from the service defined by the RSTransaction.  This function uses the dataFromRSTransaction function to retrieve an NSData object and then converts it to an NSString object.

*dictionaryFromRSTransaction(transaction: RSTransaction, completionHandler handler:  RSNetworking.dictionaryFromRSTransactionCompletionCompletionClosure):

 Retrieves an NSDictionary object from the service defined by the RSTransaction.  This function uses the dataFromRSTransaction function to retrieve an NSData object and then converts it to an NSDictionary object.  The data returned from the URL should be in JSON format for this function to work properly.

*imageFromRSTransaction(transaction: RSTransaction, completionHandler handler:  RSNetworking.imageFromRSTransactionCompletionCompletionClosure):

Retrieves an UIImage object from the service defined by the RSTransaction.  This function uses the dataFromRSTransaction function to retrieve an NSData object and then converts it to an UIImage object.

Hopefully others will find this library useful.  To receive notifications when the RSNetworking library is updated, please subscribe to my twitter feed.  You can download the code from GitHub here:  https://github.com/hoffmanjon/RSNetworking