Swiftly Salesforce

Swiftly Salesforce is a framework for the rapid development of native iOS mobile apps that interact with the Salesforce Platform.

• Written entirely in Swift, Apple's "modern programming language that is safe, fast and interactive."
• Enables elegant, painless coding for complex, asynchronous Salesforce API interactions
• Manages the Salesforce OAuth2 authorization process (a.k.a. the "OAuth dance") automatically and transparently
• Simpler and lighter alternative to the Salesforce Mobile SDK for iOS
• Easy to install and update

How do I set up Swiftly Salesforce?

You can be up and running in under 5 minutes by following these steps (if you're already familiar with the relevant procedure; if not, see the appendix):

1. Get a free Salesforce Developer Edition
2. Set up a Salesforce Connected App that will be the server to your iOS mobile app
3. Register your Connected App's callback URL scheme with iOS (see appendix)
4. Add Swiftly Salesforce to your Xcode project:

• Add pod 'SwiftlySalesforce' to your project's Podfile (see appendix)
• Or just copy these 7 Swift files, and add the dependent frameworks

1. Configure your app delegate for Swiftly Salesforce (see appendix)
2. Add an ATS exception for salesforce.com (see appendix)

Minimum requirements:

• iOS 9.1
• Swift 2
• Xcode 7

How do I use Swiftly Salesforce?

Swiftly Salesforce leverages Alamofire and PromiseKit, two very widely-adopted frameworks, for elegant handling of networking requests and asynchronous operations. Below are some examples to illustrate how to use Swiftly Salesforce, and how you can chain complex asynchronous calls. You can also find a complete example app here; it retrieves a user's task records from Salesforce, and enables the user to update the status of a task.

Swiftly Salesforce will automatically manage the entire Salesforce OAuth2 process (a.k.a. the "OAuth dance"). If Swiftly Salesforce has a valid access token, it will include that token in the header of every API request. If the token has expired, and Salesforce rejects the request, then Swiftly Salesforce will attempt to refresh the access token, without bothering the user to re-enter the username and password. If Swiftly Salesforce doesn't have a valid access token, or is unable to refresh it, then Swiftly Salesforce will direct the user to the Salesforce-hosted login page.

Example: Retrieve a Salesforce Record

The following will retrieve all the fields for the specified account record:

SalesforceAPI.ReadRecord(type: "Account", id: "0013000001FjCcF").request()

To specify which fields should be retrieved:

let fields = ["AccountNumber", "BillingCity", "MyCustomField__c"]
SalesforceAPI.ReadRecord(type: "Account", id: "0013000001FjCcF", fields: fields).request()

Note that request() is an asynchronous function, whose return value is a "promise" that will be fulfilled at some point in the future:

let promise: Promise<AnyObject> = SalesforceAPI.ReadRecord(type: "Account", id: "0013000001FjCcF").request()

And we can add a closure that will be called later, when the promise is fulfilled:

promise.then {
	(json) -> () in
	// Parse the JSON and do stuff
}

Example: Update a Salesforce Record

SalesforceAPI.UpdateRecord(type: "Task", id: "00T1500001h3V5NEAU", fields: ["Status": "Completed"]).request()
.then {
	(_) -> () in
	// Update the local model
}.always {
	// Update the UI
}

The always closure will be called regardless of success or failure elsewhere in the promise chain.

Example: Querying

let soql = "SELECT Id,Name FROM Account WHERE BillingPostalCode = '\(postalCode)'"
SalesforceAPI.Query(soql: soql).request()

See the next example for handling the query results

Example: Chaining Asynchronous Requests

Let's say we want to retrieve a random zip/postal code from a custom Apex REST resource, and then use that zip code in a query:

// Chained asynch requests 
// (Enclosing in "firstly" block is optional; just keeps things nicely laid out)
firstly {
	// Make GET request of custom Apex REST resource
	SalesforceAPI.ApexRest(method: "GET", path: "/MyApexResourceThatEmitsRandomZip").request()
}.then {
	// Query accounts with that zip code
	(result) -> Promise<AnyObject> in
	guard let zip = result["zip"] as? String else {
		throw NSError(domain: "TaskForce", code: -100, userInfo: nil)
	}
	let soql = "SELECT Id,Name FROM Account WHERE BillingPostalCode = '\(zip)'"
	return SalesforceAPI.Query(soql: soql).request()
}.then {
	// Parse JSON response
	(result) -> () in
	guard let records = result["records"] as? [[String: AnyObject]] else {
		throw NSError(domain: "TaskForce", code: -101, userInfo: nil)
	}
	for record in records {
	    if let id = record["Id"] as? String, name = record["Name"] as? String {
	        print("Account ID = \(id); name = \(name)")
        }
    }
}

You could repeat this chaining multiple times, feeding the result of one asynchronous operation as the input to the next operation. Or you could spawn multiple, simultaneous operations and easily specify logic to be executed when all operations complete, when the first completes, when any fails, etc. PromiseKit is an amazingly-powerful framework for handling multiple asynchronous operations that would otherwise be very difficult to coordinate. See PromiseKit documentation for more examples.

Example: Handling Errors

The following code is from the example file, TaskStore.swift and shows how to handle errors:

firstly {
	SalesforceAPI.Identity.request()
}.then {
	// Extract user ID from JSON result
	(result) -> String in
	guard let userID = result["user_id"] as? String else {
		throw NSError(domain: "TaskForce", code: -100, userInfo: nil)
	}
	return userID
}.then {
	// Query tasks owned by user
	(userID) -> Promise<AnyObject> in
	let soql = "SELECT Id,Subject,Status,What.Name FROM Task WHERE OwnerId = '\(userID)' ORDER BY CreatedDate DESC"
	return SalesforceAPI.Query(soql: soql).request()
}.then {
	// Parse JSON response into Task instances
	(result) -> () in
	guard let records = result["records"] as? [[String: AnyObject]] else {
		throw NSError(domain: "TaskForce", code: -101, userInfo: nil)
	}
	let tasks = records.map { Task(dictionary: $0) }
	self.cache = tasks
	fulfill(tasks)
}.error {
	// Any errors in the chain would be caught here
	(error) -> Void in
	reject(error)
}

You could also recover from an error, and continue with the chain, using a recover closure. The following snippet is from PromiseKit's documentation:

CLLocationManager.promise().recover { err in
    guard !err.fatal else { throw err }
    return CLLocationChicago
}.then { location in
    // the user’s location, or Chicago if an error occurred
}.error { err in
    // the error was fatal
}

Example: Log Out

If you want to log out the current Salesforce user, and then clear any locally-cached data, you could call the following. Swiftly Salesforce will revoke and remove any stored credentials, and automatically display a Safari View Controller with the Salesforce login page, ready for another user to log in.

// Call this when "Log Out" button is tapped, for example
if let app = UIApplication.sharedApplication().delegate as? LoginViewPresentable {
	app.logOut().then {
		() -> () in
		// User's authorization now revoked - clear local data cache
		return
	}
}

Dependent Frameworks

The great Swift frameworks leveraged by Swiftly Salesforce:

• PromiseKit (Version 3): "Not just a promises implementation, it is also a collection of helper functions that make the typical asynchronous patterns we use as iOS developers delightful too."
• Alamofire (Version 3): "Elegant HTTP Networking in Swift"
• Locksmith: "A powerful, protocol-oriented library for working with the keychain in Swift."

Main Components of Swiftly Salesforce

• SalesforceAPI: Acts as a 'router' for Alamofire requests. The more important, or commonly-used Salesforce REST API endpoints are represented as enum values, and I'll add more endpoints over time. You can also easily create Alamofire requests for your custom Apex REST endpoints, for example, by following the pattern established in this file.

• Credentials: Swift struct that holds tokens, and other data, required for each request made to the Salesforce REST API. These values are stored securely in the iOS keychain.

• Extensions: Swift extensions used by other components of Swiftly Salesforce. The extensions that you'll likely use in your own code are NSDateFormatter.SalesforceDateTime, and NSDateFormatter.SalesforceDate, for converting Salesforce date/time and date fields to and from strings for JSON serialization.

• OAuth2Manager: Singleton that coordinates the OAuth2 authorization process, and securely stores and retrieves the resulting access token. The access token must be included in the header of every HTTP request to the Salesforce REST API. If the access token has expired, the OAuth2Manager will attempt to refresh it. If the refresh process fails, then the OAuth2Manager will call on its delegate to authenticate the user, that is, to display a Salesforce-hosted form into which the user would enter his/her username and password. The default implementation uses a Safari View Controller (new in iOS 9) to authenticate the user via the OAuth2 'user-agent' flow. Though 'user-agent' flow is more complex than the OAuth2 'username-password' flow, it is the preferred method of authenticating users to Salesforce, since their passwords are never handled by the client application.

Resources

If you're new to Swift, the Salesforce Platform, or the Salesforce REST API, you might find the following resources useful.

• Salesforce REST API Developer's Guide
• Salesforce App Cloud: aka the Salesforce Platform
• Salesforce Developers: official Salesforce developers' site; training, documentation, SDKs, etc.
• Salesforce Partner Community: "Innovate, grow, connect" with Salesforce ISVs. Join the Salesforce + iOS Mobile Chatter group
• Salesforce Mobile SDK for iOS: 'official' SDK for developing mobile apps. Written in Objective-C. Available for Android, too
• A Salesforce Swift App: blog post on using Swift with the Salesforce Mobile SDK. By Jonathan Jenkins
• Salesforce OAuth2 Made Easy For Native iOS Apps: blog post by Quinton Wall
• When to Use the Salesforce1 Platform vs. Creating Custom Apps
• Alamofire: Swift version of AFNetworking, "...One of the most popular third-party libraries on iOS and OS X." Tutorial here.
• Functional Swift: great book for learning Swift 2, by the team at objc.io. See their other books on Advanced Swift, and Core Data.
• iOS Apps with REST APIs: great book for getting started with Swift, REST APIs, JSON, and Alamofire. "Only the nitty gritty that you need to get real work done now: interfacing with your web services and displaying the results in your UI." By Christina Moulton of GrokSwift
• Salesforce Mobile SDK Quick Start: blog post by William Welbes

About Me

I'm a senior technical 'evangelist' at Salesforce, and I work with ISV partners who are building applications on the Salesforce Platform.

Contact

Questions, suggestions, bug reports and code contributions welcome:

• Open a GitHub issue
• Twitter @mike4aday
• Join the Salesforce Partner Community and post to the 'Salesforce + iOS Mobile' Chatter group

Appendix

Add Swiftly Salesforce to Your CocoaPods Podfile

Adding Swiftly Salesforce to a simple Podfile:

platform :ios, '9.1'
use_frameworks!

pod 'SwiftlySalesforce'
# Another pod here

See Podfile for more details

Register Your Connected App's Callback URL Scheme with iOS

Upon successful OAuth2 authorization, Salesforce will redirect the Safari View Controller back to the callback URL that you specified in your Connected App settings, and will append the access token (among other things) to that callback URL. Add the following to your app's .plist file, so iOS will know how to handle the URL, and will pass it to your app's delegate.

<!-- ADD TO YOUR APP'S .PLIST FILE -->
<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLName</key>
    <string>SalesforceOAuth2CallbackURLScheme</string>
    <key>CFBundleURLSchemes</key>
    <array>
      <string><!-- YOUR CALLBACK URL'S SCHEME HERE (scheme only, not entire URL) --></string>
    </array>
  </dict>
</array>

Then, you just need to add a single line in your app delegate class so that Swiftly Salesforce will handle the callback URL and the appended credentials.

func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject) -> Bool {
	handleRedirectURL(url)
	return true
}

Configure your App Delegate for Swiftly Salesforce

Update your app delegate class so that it:

• Configures Swiftly Salesforce with your Connected App's consumer key and callback URL
• Implements LoginViewPresentable - you don't have to implement any methods, though, thanks to the magic of Swift 2's protocol extensions
• Calls handleRedirectURL(NSURL:) when asked by iOS to open the callback URL.

See below:

import UIKit
import SwiftlySalesforce

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, LoginViewPresentable {
	
	var window: UIWindow?
	let consumerKey = "<<YOUR CONNECTED APP'S CONSUMER KEY>>"
	let redirectURL = NSURL(string: "<<YOUR CONNECTED APP'S CALLBACK URL>>")!
	
	func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
		OAuth2Manager.sharedInstance.configureWithConsumerKey(consumerKey, redirectURL: redirectURL)
		OAuth2Manager.sharedInstance.authenticationDelegate = self
		return true
	}
	
	func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject) -> Bool {
		handleRedirectURL(url)
		return true
	}
}

Communities and OAuth2

If the mobile app's users are members of a Salesforce Community, then they should authorize with the Community URL, rather than the default login.salesforce.com. For example, if the hostname portion of the Community authorization URL is acme.force.com, then configure the OAuth2Manager class with an additional parameter that specifies the hostname:

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
		OAuth2Manager.sharedInstance.configureWithConsumerKey(consumerKey, redirectURL: redirectURL, hostname: "acme.force.com")
		OAuth2Manager.sharedInstance.authenticationDelegate = self
		return true
}

For more information, see Configure Authentication Flows with OAuth.

Add an ATS Exception for Salefsorce

As of this writing, you need to add an application transport security (ATS) exception to your iOS application's .plist file to allow it to connect to salesforce.com, as follows:

<!-- ADD TO YOUR APP'S .PLIST FILE -->
<key>NSAppTransportSecurity</key>
<dict>
	<key>NSExceptionDomains</key>
	<dict>
		<key>salesforce.com</key>
		<dict>
			<key>NSExceptionRequiresForwardSecrecy</key>
			<false/>
			<key>NSIncludesSubdomains</key>
			<true/>
		</dict>
	</dict>
</dict>