Updated Twitter Package - CS193p Lecture 10 - Updated for Swift 2.0 and Xcode 7.2

MediaItem.swift

//
//  MediaItem.swift
//  Twitter
//
//  Created by CS193p Instructor.
//  Copyright (c) 2015 Stanford University. All rights reserved.
//

import Foundation

// holds the network url and aspectRatio of an image attached to a Tweet
// created automatically when a Tweet object is created

public struct MediaItem
{
    public var url: NSURL!
    public var aspectRatio: Double = 0
    
    public var description: String { return (url.absoluteString ?? "no url") + " (aspect ratio = \(aspectRatio))" }
    
    // MARK: - Private Implementation

    init?(data: NSDictionary?) {
        var valid = false
        if let urlString = data?.valueForKeyPath(TwitterKey.MediaURL) as? NSString {
            if let url = NSURL(string: urlString as String) {
                self.url = url
                let h = data?.valueForKeyPath(TwitterKey.Height) as? NSNumber
                let w = data?.valueForKeyPath(TwitterKey.Width) as? NSNumber
                if h != nil && w != nil && h?.doubleValue != 0 {
                    aspectRatio = w!.doubleValue / h!.doubleValue
                    valid = true
                }
            }
        }
        if !valid {
            return nil
        }
    }
    
    struct TwitterKey {
        static let MediaURL = "media_url_https"
        static let Width = "sizes.small.w"
        static let Height = "sizes.small.h"
    }
}

Tweet.swift

//
//  Tweet.swift
//  Twitter
//
//  Created by CS193p Instructor.
//  Copyright (c) 2015 Stanford University. All rights reserved.
//

import Foundation

// a simple container class which just holds the data in a Tweet
// IndexedKeywords are substrings of the Tweet's text
// for example, a hashtag or other user or url that is mentioned in the Tweet
// note carefully the comments on the two range properties in an IndexedKeyword
// Tweet instances re created by fetching from Twitter using a TwitterRequest

public class Tweet : CustomStringConvertible
{
    public var text: String
    public var user: User
    public var created: NSDate
    public var id: String?
    public var media = [MediaItem]()
    public var mediaMentions = [IndexedKeyword]()
    public var hashtags = [IndexedKeyword]()
    public var urls = [IndexedKeyword]()
    public var userMentions = [IndexedKeyword]()

    public struct IndexedKeyword: CustomStringConvertible
    {
        public var keyword: String              // will include # or @ or http:// prefix
        public var range: Range<String.Index>   // index into the Tweet's text property only
        public var nsrange = NSMakeRange(0, 0)              // index into an NS[Attributed]String made from the Tweet's text

        public init?(data: NSDictionary?, inText: String, prefix: String?) {
            let indices = data?.valueForKeyPath(TwitterKey.Entities.Indices) as? NSArray
            if let startIndex = (indices?.firstObject as? NSNumber)?.integerValue {
                if let endIndex = (indices?.lastObject as? NSNumber)?.integerValue {
                    let length = inText.characters.count
                    if length > 0 {
                        let start = max(min(startIndex, length-1), 0)
                        let end = max(min(endIndex, length), 0)
                        if end > start {
                            range = inText.startIndex.advancedBy(start)...inText.startIndex.advancedBy(end-1)
                            keyword = inText.substringWithRange(range)
                            if prefix != nil && !keyword.hasPrefix(prefix!) && start > 0 {
                                range = inText.startIndex.advancedBy(start-1)...inText.startIndex.advancedBy(end-2)
                                keyword = inText.substringWithRange(range)
                            }
                            if prefix == nil || keyword.hasPrefix(prefix!) {
                                nsrange = inText.rangeOfString(keyword, nearRange: NSMakeRange(startIndex, endIndex-startIndex))
                                if nsrange.location != NSNotFound {
                                    return
                                }
                            }
                        }
                    }
                }
            }
            return nil
        }

        public var description: String { get { return "\(keyword) (\(nsrange.location), \(nsrange.location+nsrange.length-1))" } }
    }
    
    public var description: String { return "\(user) - \(created)\n\(text)\nhashtags: \(hashtags)\nurls: \(urls)\nuser_mentions: \(userMentions)" + (id == nil ? "" : "\nid: \(id!)") }

    // MARK: - Private Implementation

    init?(data: NSDictionary?) {
        if let user = User(data: data?.valueForKeyPath(TwitterKey.User) as? NSDictionary) {
            self.user = user
            if let text = data?.valueForKeyPath(TwitterKey.Text) as? String {
                self.text = text
                if let created = (data?.valueForKeyPath(TwitterKey.Created) as? String)?.asTwitterDate {
                    self.created = created
                    id = data?.valueForKeyPath(TwitterKey.ID) as? String
                    if let mediaEntities = data?.valueForKeyPath(TwitterKey.Media) as? NSArray {
                        for mediaData in mediaEntities {
                            if let mediaItem = MediaItem(data: mediaData as? NSDictionary) {
                                media.append(mediaItem)
                            }
                        }
                        mediaMentions = getIndexedKeywords(mediaEntities, inText: text, prefix: "h")
                    }
                    let hashtagMentionsArray = data?.valueForKeyPath(TwitterKey.Entities.Hashtags) as? NSArray
                    hashtags = getIndexedKeywords(hashtagMentionsArray, inText: text, prefix: "#")
                    let urlMentionsArray = data?.valueForKeyPath(TwitterKey.Entities.URLs) as? NSArray
                    urls = getIndexedKeywords(urlMentionsArray, inText: text, prefix: "h")
                    let userMentionsArray = data?.valueForKeyPath(TwitterKey.Entities.UserMentions) as? NSArray
                    userMentions = getIndexedKeywords(userMentionsArray, inText: text, prefix: "@")
                    return
                }
            }
        }
        // we've failed
        // but compiler won't let us out of here with non-optional values unset
        // so set them to anything just to able to return nil
        // we could make these implicitly-unwrapped optionals, but they should never be nil, ever
        self.text = ""
        self.user = User()
        self.created = NSDate()
        return nil
    }

    private func getIndexedKeywords(dictionary: NSArray?, inText: String, prefix: String? = nil) -> [IndexedKeyword] {
        var results = [IndexedKeyword]()
        if let indexedKeywords = dictionary {
            for indexedKeywordData in indexedKeywords {
                if let indexedKeyword = IndexedKeyword(data: indexedKeywordData as? NSDictionary, inText: inText, prefix: prefix) {
                    results.append(indexedKeyword)
                }
            }
        }
        return results
    }
    
    struct TwitterKey {
        static let User = "user"
        static let Text = "text"
        static let Created = "created_at"
        static let ID = "id_str"
        static let Media = "entities.media"
        struct Entities {
            static let Hashtags = "entities.hashtags"
            static let URLs = "entities.urls"
            static let UserMentions = "entities.user_mentions"
            static let Indices = "indices"
        }
    }
}

private extension NSString {
    func rangeOfString(substring: NSString, nearRange: NSRange) -> NSRange {
        var start = max(min(nearRange.location, length-1), 0)
        var end = max(min(nearRange.location + nearRange.length, length), 0)
        var done = false
        while !done {
            let range = rangeOfString(substring as String, options: NSStringCompareOptions(), range: NSMakeRange(start, end-start))
            if range.location != NSNotFound {
                return range
            }
            done = true
            if start > 0 { start-- ; done = false }
            if end < length { end++ ; done = false }
        }
        return NSMakeRange(NSNotFound, 0)
    }
}

private extension String {
    var asTwitterDate: NSDate? {
        get {
            let dateFormatter = NSDateFormatter()
            dateFormatter.locale = NSLocale(localeIdentifier: "en_US")
            dateFormatter.dateFormat = "EEE MMM dd HH:mm:ss Z yyyy"
            return dateFormatter.dateFromString(self)
        }
    }
}

TwitterRequest.swift

//
//  TwitterRequest.swift
//  Twitter
//
//  Created by CS193p Instructor.
//  Copyright (c) 2015 Stanford University. All rights reserved.
//

import Foundation
import Accounts
import Social
import CoreLocation

// Simple Twitter query class
// Create an instance of it using one of the initializers
// Set the requestType and parameters (if not using a convenience init that sets those)
// Call fetch (or fetchTweets if fetching Tweets)
// The handler passed in will be called when the information comes back from Twitter
// Once a successful fetch has happened,
//   a follow-on TwitterRequest to get more Tweets (newer or older) can be created
//   using the requestFor{Newer,Older} methods

private var twitterAccount: ACAccount?

public class TwitterRequest
{
    public var requestType: String
    public var parameters = Dictionary<String, String>()
    
    // designated initializer
    public init(_ requestType: String, _ parameters: Dictionary<String, String> = [:]) {
        self.requestType = requestType
        self.parameters = parameters
    }
    
    // convenience initializer for creating a TwitterRequest that is a search for Tweets
    public convenience init(search: String, count: Int = 0, _ resultType: SearchResultType = .Mixed, _ region: CLCircularRegion? = nil) {
        var parameters = [TwitterKey.Query : search]
        if count > 0 {
            parameters[TwitterKey.Count] = "\(count)"
        }
        switch resultType {
            case .Recent: parameters[TwitterKey.ResultType] = TwitterKey.ResultTypeRecent
            case .Popular: parameters[TwitterKey.ResultType] = TwitterKey.ResultTypePopular
            default: break
        }
        if let geocode = region {
            parameters[TwitterKey.Geocode] = "\(geocode.center.latitude),\(geocode.center.longitude),\(geocode.radius/1000.0)km"
        }
        self.init(TwitterKey.SearchForTweets, parameters)
    }

    public enum SearchResultType {
        case Mixed
        case Recent
        case Popular
    }
    
    // convenience "fetch" for when self is a request that returns Tweet(s)
    // handler is not necessarily invoked on the main queue

    public func fetchTweets(handler: ([Tweet]) -> Void) {
        fetch { results in
            var tweets = [Tweet]()
            var tweetArray: NSArray?
            if let dictionary = results as? NSDictionary {
                if let tweets = dictionary[TwitterKey.Tweets] as? NSArray {
                    tweetArray = tweets
                } else if let tweet = Tweet(data: dictionary) {
                    tweets = [tweet]
                }
            } else if let array = results as? NSArray {
                tweetArray = array
            }
            if tweetArray != nil {
                for tweetData in tweetArray! {
                    if let tweet = Tweet(data: tweetData as? NSDictionary) {
                        tweets.append(tweet)
                    }
                }
            }
            handler(tweets)
        }
    }

    public typealias PropertyList = AnyObject

    // send an arbitrary request off to Twitter
    // calls the handler (not necessarily on the main queue)
    //   with the JSON results converted to a Property List
    
    public func fetch(handler: (results: PropertyList?) -> Void) {
        performTwitterRequest(SLRequestMethod.GET, handler: handler)
    }
    
    // generates a request for older Tweets than were returned by self
    // only makes sense if self has done a fetch already
    // only makes sense for requests for Tweets

    public var requestForOlder: TwitterRequest? {
        return min_id != nil ? modifiedRequest(parametersToChange: [TwitterKey.MaxID : min_id!]) : nil
    }
    
    // generates a request for newer Tweets than were returned by self
    // only makes sense if self has done a fetch already
    // only makes sense for requests for Tweets

    public var requestForNewer: TwitterRequest? {
        return (max_id != nil) ? modifiedRequest(parametersToChange: [TwitterKey.SinceID : max_id!], clearCount: true) : nil
    }
    
    // MARK: - Private Implementation
    
    // creates an appropriate SLRequest using the specified SLRequestMethod
    // then calls the other version of this method that takes an SLRequest
    // handler is not necessarily called on the main queue
    
    func performTwitterRequest(method: SLRequestMethod, handler: (PropertyList?) -> Void) {
        let jsonExtension = (self.requestType.rangeOfString(JSONExtension) == nil) ? JSONExtension : ""
        let request = SLRequest(
            forServiceType: SLServiceTypeTwitter,
            requestMethod: method,
            URL: NSURL(string: "\(TwitterURLPrefix)\(self.requestType)\(jsonExtension)"),
            parameters: self.parameters
        )
        performTwitterRequest(request, handler: handler)
    }
    
    // sends the request to Twitter
    // unpackages the JSON response into a Property List
    // and calls handler (not necessarily on the main queue)

    func performTwitterRequest(request: SLRequest, handler: (PropertyList?) -> Void) {
        if let account = twitterAccount {
            request.account = account
            request.performRequestWithHandler { (jsonResponse, httpResponse, _) in
                var propertyListResponse: PropertyList?
                do {
                    if jsonResponse != nil {
                        propertyListResponse = try NSJSONSerialization.JSONObjectWithData(
                            jsonResponse,
                            options: NSJSONReadingOptions.MutableLeaves
                        )
                    }
                } catch let error as NSError {
                    print(error)
                }

                self.synchronize {
                    self.captureFollowonRequestInfo(propertyListResponse)
                }
                handler(propertyListResponse)
            }
        } else {
            let accountStore = ACAccountStore()
            let twitterAccountType = accountStore.accountTypeWithAccountTypeIdentifier(ACAccountTypeIdentifierTwitter)
            accountStore.requestAccessToAccountsWithType(twitterAccountType, options: nil) { (granted, _) in
                if granted {
                    if let account = accountStore.accountsWithAccountType(twitterAccountType)?.last as? ACAccount {
                        twitterAccount = account
                        self.performTwitterRequest(request, handler: handler)
                    } else {
                        let error = "Couldn't discover Twitter account type."
                        self.log(error)
                        handler(error)
                    }
                } else {
                    let error = "Access to Twitter was not granted."
                    self.log(error)
                    handler(error)
                }
            }
        }
    }
    
    private var min_id: String? = nil
    private var max_id: String? = nil
    
    // modifies parameters in an existing request to create a new one
    
    private func modifiedRequest(parametersToChange parametersToChange: Dictionary<String,String>, clearCount: Bool = false) -> TwitterRequest {
        var newParameters = parameters
        for (key, value) in parametersToChange {
            newParameters[key] = value
        }
        if clearCount { newParameters[TwitterKey.Count] = nil }
        return TwitterRequest(requestType, newParameters)
    }
    
    // captures the min_id and max_id information
    // to support requestForNewer and requestForOlder

    private func captureFollowonRequestInfo(propertyListResponse: PropertyList?) {
        if let responseDictionary = propertyListResponse as? NSDictionary {
            self.max_id = responseDictionary.valueForKeyPath(TwitterKey.SearchMetadata.MaxID) as? String
            if let next_results = responseDictionary.valueForKeyPath(TwitterKey.SearchMetadata.NextResults) as? String {
                for queryTerm in next_results.componentsSeparatedByString(TwitterKey.SearchMetadata.Separator) {
                    if queryTerm.hasPrefix("?\(TwitterKey.MaxID)=") {
                        let next_id = queryTerm.componentsSeparatedByString("=")
                        if next_id.count == 2 {
                            self.min_id = next_id[1]
                        }
                    }
                }
            }
        }
    }
    
    // debug println with identifying prefix
    
    private func log(whatToLog: AnyObject) {
        debugPrint("TwitterRequest: \(whatToLog)")
    }
    
    // synchronizes access to self across multiple threads

    private func synchronize(closure: () -> Void) {
        objc_sync_enter(self)
        closure()
        objc_sync_exit(self)
    }
    
    // constants

    let JSONExtension = ".json"
    let TwitterURLPrefix = "https://api.twitter.com/1.1/"
    
    // keys in Twitter responses/queries

    struct TwitterKey {
        static let Count = "count"
        static let Query = "q"
        static let Tweets = "statuses"
        static let ResultType = "result_type"
        static let ResultTypeRecent = "recent"
        static let ResultTypePopular = "popular"
        static let Geocode = "geocode"
        static let SearchForTweets = "search/tweets"
        static let MaxID = "max_id"
        static let SinceID = "since_id"
        struct SearchMetadata {
            static let MaxID = "search_metadata.max_id_str"
            static let NextResults = "search_metadata.next_results"
            static let Separator = "&"
        }
    }
}

User.swift

//
//  User.swift
//  Twitter
//
//  Created by CS193p Instructor.
//  Copyright (c) 2015 Stanford University. All rights reserved.
//

import Foundation

// container to hold data about a Twitter user

public struct User: CustomStringConvertible
{
    public var screenName: String
    public var name: String
    public var profileImageURL: NSURL?
    public var verified: Bool = false
    public var id: String!
    
    public var description: String { let v = verified ? " ✅" : ""; return "@\(screenName) (\(name))\(v)" }

    // MARK: - Private Implementation

    init?(data: NSDictionary?) {
        let name = data?.valueForKeyPath(TwitterKey.Name) as? String
        let screenName = data?.valueForKeyPath(TwitterKey.ScreenName) as? String
        if name != nil && screenName != nil {
            self.name = name!
            self.screenName = screenName!
            self.id = data?.valueForKeyPath(TwitterKey.ID) as? String
            if let verified = data?.valueForKeyPath(TwitterKey.Verified)?.boolValue {
                self.verified = verified
            }
            if let urlString = data?.valueForKeyPath(TwitterKey.ProfileImageURL) as? String {
                self.profileImageURL = NSURL(string: urlString)
            }
        } else {
            return nil
        }
    }
    
    var asPropertyList: AnyObject {
        var dictionary = Dictionary<String,String>()
        dictionary[TwitterKey.Name] = self.name
        dictionary[TwitterKey.ScreenName] = self.screenName
        dictionary[TwitterKey.ID] = self.id
        dictionary[TwitterKey.Verified] = verified ? "YES" : "NO"
        dictionary[TwitterKey.ProfileImageURL] = profileImageURL?.absoluteString
        return dictionary
    }

    
    init() {
        screenName = "Unknown"
        name = "Unknown"
    }
    
    struct TwitterKey {
        static let Name = "name"
        static let ScreenName = "screen_name"
        static let ID = "id_str"
        static let Verified = "verified"
        static let ProfileImageURL = "profile_image_url"
    }
}