Build iOS apps fast on the Salesforce Platform with Swiftly Salesforce:

• Written entirely in Swift 3.
• Uses promises to simplify complex, asynchronous Salesforce API interactions
• Manages the Salesforce OAuth2 process (the "OAuth dance") automatically and transparently
• Simpler and lighter alternative to the Salesforce Mobile SDK for iOS
• Easy to install and update

You can be up and running in a few minutes by following these steps:

1. Get a free Salesforce Developer Edition
2. Create a Salesforce Connected App in your new Developer Edition
3. Add Swiftly Salesforce to your Xcode project
   • CocoaPods: add pod 'SwiftlySalesforce' to your Podfile
   • Carthage: add github "mike4aday/SwiftlySalesforce" to your Cartfile
4. Configure your app delegate (example)
5. Register your Connected App's callback URL scheme with iOS (example)

• iOS 10
• Swift 3
• Xcode 8

Documentation is here. See especially the public methods of the Salesforce class - those are likely all you'll need to call from your code.

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 the logged-in user’s task records from Salesforce, and lets the user update the status of a task.

Swiftly Salesforce will automatically manage the entire Salesforce OAuth2 process (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 form.

Behind the scenes, Swiftly Salesforce leverages Alamofire and PromiseKit, two very widely-adopted frameworks, for elegant handling of networking requests and asynchronous operations.

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

salesforce.retrieve(type: "Account", id: "0013000001FjCcF")

To specify which fields should be retrieved:

let fields = ["AccountNumber", "BillingCity", "MyCustomField__c"]
salesforce.retrieve(type: "Account", id: "0013000001FjCcF", fields: fields)

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

let promise = salesforce.retrieve(type: "Account", id: "0013000001FjCcF")

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

promise.then {
	queryResult in
	for record in queryResult.records {
		// Parse JSON dictionary of record fields & values, and do interesting stuff…
	}
}

You can retrieve multiple records in parallel, and wait for them all before proceeding:

first {
	// (Enclosing this in a ‘first’ block is optional, and can keep things neat.)
	let ids = ["001i0000020i19F", "001i0000034i18A", "001i0000020i22B"]
	salesforce.retrieve(type: "Account", ids: ids, fields: ["Name", "BillingPostalCode"])
}.then {
	records -> () in
	for record in records {
		if let name = record["Name"] as? String {
			debugPrint(name)
		}
	}
}.catch {
	error in
	// Handle error...
}

salesforce.update(type: "Task", id: "00T1500001h3V5NEAU", fields: ["Status": "Completed"])
.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.

let soql = "SELECT Id,Name FROM Account WHERE BillingPostalCode = '\(postalCode)'"
salesforce.query(soql: soql).then {
  queryResult -> () in
  // Handle the QueryResult
}.catch {
  error in
  // Handle the error
}

You can also execute multiple queries at once and wait for them all to complete before proceeding:

first {
	let queries = ["SELECT Name FROM Account", "SELECT Id FROM Contact", "Select Owner.Name FROM Lead"]
	salesforce.query(soql: queries)
}.then {
	queryResults -> () in
	// Results are in the same order as the queries
}.catch {
	error in
	// Handle the error
}

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
first {
    // Make GET request of custom Apex REST resource
    salesforce.apexRest(path: "/MyApexResourceThatEmitsRandomZip")
}.then {
    // Query accounts in that zip code
    result in
    guard let zip = result["zip"] as? String else {
        throw TaskForceError.generic(100, “Can’t get random zip code from our custom REST endpoint!”)
    }
    let soql = "SELECT Id,Name FROM Account WHERE BillingPostalCode = '\(zip)'"
    return salesforce.query(soql: soql)
}.then {
    queryResult in
    for record in queryResult.records {
        if let name = record["Name"] as? String {
          print("Account name = \(name)")
        }
    }
}

You could repeat this chaining multiple times, feeding the result of one asynchronous operation as the input to the next. Or you could spawn multiple, simultaneous operations and easily specify logic to be executed when all operations complete, or when just the first completes, or when any one operation 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.

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

first {
    // Get ID of current user
    salesforce.identity()
}.then {
    // Query tasks owned by user
    userInfo in
    guard let userID = userInfo.userID else {
        throw TaskForceError.generic(code: 100, message: "Can't determine user ID")
    }
    let soql = "SELECT Id,Subject,Status,What.Name FROM Task WHERE OwnerId = '\(userID)' ORDER BY CreatedDate DESC"
    return salesforce.query(soql: soql)
}.then {
    // Parse JSON into Task instances
    (result: QueryResult) -> () in
    let tasks = result.records.map { Task(dictionary: $0) }
    // Do something interesting with the tasks…
}.catch {
    error in
    // Handle the 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
}.catch { err in
    // the error was fatal
}

If, for example, you want to determine whether the user has permission to update or delete a record so you can disable editing in your UI, or if you want to retrieve all the options in a picklist, rather than hardcoding them in your mobile app, then call salesforce.describe(type:) to retrieve an object's metadata:

first {
    salesforce.describe(type: "Account")
}.then {
    (accountMetadata) -> () in
    saveButton.enabled = accountMetadata.isUpdateable
    let industryOptions = accountMetadata.fields["Industry"]?.picklistValues
}.catch {
    error in
    debugPrint(error)
}

You can retrieve metadata for multiple objects in parallel, and wait for all before proceeding:

first {
  salesforce.describe(types: ["Account", "Contact", "Task", "CustomObject__c"])
}.then {
  results -> () in
  // results is an array of ObjectDescriptions, in the same order as requested
}.catch {
  error in
  // Handle the error
}

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 your app's "Log Out" button is tapped, for example
if let app = UIApplication.shared.delegate as? LoginDelegate {
    app.logout().then {
        () -> () in
        // Clear any cached data and reset the UI
        return
    }.catch {
        error in
        debugPrint(error)
    }
}

target 'MyApp' do
  use_frameworks!
  pod 'SwiftlySalesforce'
  # Another pod here
end

import UIKit
import SwiftlySalesforce

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, LoginDelegate /* 1 */ {

    var window: UIWindow?

    /// Salesforce Connected App properties (replace with your own…) /* 2 */
    let consumerKey = "<YOUR CONNECTED APP’S CONSUMER KEY HERE>" 
    let redirectURL = URL(string: "<YOUR CONNECTED APP’S REDIRECT URL HERE>")!

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        configureSalesforce(consumerKey: consumerKey, redirectURL: redirectURL) /* 3 */
        return true
    }

    func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
        handleRedirectURL(url: url) /* 3 */
        return true
    }
}

Note the following in the above example:

1. Your app delegate should implement LoginDelegate
2. Replace the values for consumerKey and redirectURL with the values defined in your Connected App
3. Call configureSalesforce() and handleRedirectURL() as shown

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 callback 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>

• Salesforce.swift: This is your Swift interface to the Salesforce Platform, and likely the only file you’ll refer to. It has methods to query, retrieve, update and delete records, and to access custom Apex REST endpoints.

• Router.swift: Acts as a 'router' for Alamofire requests. The more important and commonly-used Salesforce REST API endpoints are represented as enum values, including one for custom Apex REST endpoints.

• AuthData.swift: 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: Swift extensions used by other components of Swiftly Salesforce. The extensions that you'll likely use in your own code are DateFormatter.salesforceDateTime, and DateFormatter.salesforceDate, for converting Salesforce date/time and date values to and from strings for JSON serialization.

• AuthManager.swift: 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 AuthManager will attempt to refresh it. If the refresh process fails, then AuthManager will call on its delegate to authenticate the user, that is, to display a Salesforce-hosted web login form. 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 credentials are never handled by the client application.

The great Swift frameworks leveraged by Swiftly Salesforce:

• PromiseKit: "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: "Elegant HTTP Networking in Swift"
• Locksmith: "A powerful, protocol-oriented library for working with the keychain in Swift."

If you're new to 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: Salesforce-supported SDK for developing mobile apps. Written in Objective-C. Available for Android, too
• When to Use the Salesforce1 Platform vs. Creating Custom Apps

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