NetNewsWire/Shared/Favicons/FaviconDownloader.swift

317 lines
9.5 KiB
Swift
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//
// FaviconDownloader.swift
// NetNewsWire
//
// Created by Brent Simmons on 11/19/17.
// Copyright © 2017 Ranchero Software. All rights reserved.
//
import Foundation
import CoreServices
import Articles
import Account
import UniformTypeIdentifiers
import Core
extension Notification.Name {
static let FaviconDidBecomeAvailable = Notification.Name("FaviconDidBecomeAvailableNotification") // userInfo key: FaviconDownloader.UserInfoKey.faviconURL
}
final class FaviconDownloader {
private static let saveQueue = CoalescingQueue(name: "Cache Save Queue", interval: 1.0)
private let folder: String
private let diskCache: BinaryDiskCache
private var singleFaviconDownloaderCache = [String: SingleFaviconDownloader]() // faviconURL: SingleFaviconDownloader
private var remainingFaviconURLs = [String: ArraySlice<String>]() // homePageURL: array of faviconURLs that haven't been checked yet
private var currentHomePageHasOnlyFaviconICO = false
private var homePageToFaviconURLCache = [String: String]() //homePageURL: faviconURL
private var homePageToFaviconURLCachePath: String
private var homePageToFaviconURLCacheDirty = false {
didSet {
queueSaveHomePageToFaviconURLCacheIfNeeded()
}
}
private var homePageURLsWithNoFaviconURLCache = Set<String>()
private var homePageURLsWithNoFaviconURLCachePath: String
private var homePageURLsWithNoFaviconURLCacheDirty = false {
didSet {
queueSaveHomePageURLsWithNoFaviconURLCacheIfNeeded()
}
}
private let queue: DispatchQueue
private var cache = [Feed: IconImage]() // faviconURL: RSImage
struct UserInfoKey {
static let faviconURL = "faviconURL"
}
init(folder: String) {
self.folder = folder
self.diskCache = BinaryDiskCache(folder: folder)
self.queue = DispatchQueue(label: "FaviconDownloader serial queue - \(folder)")
self.homePageToFaviconURLCachePath = (folder as NSString).appendingPathComponent("HomePageToFaviconURLCache.plist")
self.homePageURLsWithNoFaviconURLCachePath = (folder as NSString).appendingPathComponent("HomePageURLsWithNoFaviconURLCache.plist")
loadHomePageToFaviconURLCache()
loadHomePageURLsWithNoFaviconURLCache()
NotificationCenter.default.addObserver(self, selector: #selector(didLoadFavicon(_:)), name: .DidLoadFavicon, object: nil)
}
// MARK: - API
func resetCache() {
cache = [Feed: IconImage]()
}
func favicon(for feed: Feed) -> IconImage? {
assert(Thread.isMainThread)
var homePageURL = feed.homePageURL
if let faviconURL = feed.faviconURL {
return favicon(with: faviconURL, homePageURL: homePageURL)
}
if homePageURL == nil {
// Base homePageURL off feedURL if needed. Wont always be accurate, but is good enough.
if let feedURL = URL(string: feed.url), let scheme = feedURL.scheme, let host = feedURL.host {
homePageURL = scheme + "://" + host + "/"
}
}
if let homePageURL = homePageURL {
return favicon(withHomePageURL: homePageURL)
}
return nil
}
func faviconAsIcon(for feed: Feed) -> IconImage? {
if let image = cache[feed] {
return image
}
if let iconImage = favicon(for: feed), let imageData = iconImage.image.dataRepresentation() {
if let scaledImage = RSImage.scaledForIcon(imageData) {
let scaledIconImage = IconImage(scaledImage)
cache[feed] = scaledIconImage
return scaledIconImage
}
}
return nil
}
func favicon(with faviconURL: String, homePageURL: String?) -> IconImage? {
let downloader = faviconDownloader(withURL: faviconURL, homePageURL: homePageURL)
return downloader.iconImage
}
func favicon(withHomePageURL homePageURL: String) -> IconImage? {
let url = homePageURL.normalizedURL
if let url = URL(string: homePageURL) {
if url.host == "nnw.ranchero.com" || url.host == "netnewswire.blog" {
return IconImage.appIcon
}
}
if homePageURLsWithNoFaviconURLCache.contains(url) {
return nil
}
if let faviconURL = homePageToFaviconURLCache[url] {
return favicon(with: faviconURL, homePageURL: url)
}
findFaviconURLs(with: url) { (faviconURLs) in
if let faviconURLs = faviconURLs {
// If the site explicitly specifies favicon.ico, it will appear twice.
self.currentHomePageHasOnlyFaviconICO = faviconURLs.count == 1
if let firstIconURL = faviconURLs.first {
let _ = self.favicon(with: firstIconURL, homePageURL: url)
self.remainingFaviconURLs[url] = faviconURLs.dropFirst()
}
}
}
return nil
}
// MARK: - Notifications
@objc func didLoadFavicon(_ note: Notification) {
guard let singleFaviconDownloader = note.object as? SingleFaviconDownloader else {
return
}
guard let homePageURL = singleFaviconDownloader.homePageURL else {
return
}
guard let _ = singleFaviconDownloader.iconImage else {
if let faviconURLs = remainingFaviconURLs[homePageURL] {
if let nextIconURL = faviconURLs.first {
let _ = favicon(with: nextIconURL, homePageURL: singleFaviconDownloader.homePageURL)
remainingFaviconURLs[homePageURL] = faviconURLs.dropFirst();
} else {
remainingFaviconURLs[homePageURL] = nil
if currentHomePageHasOnlyFaviconICO {
self.homePageURLsWithNoFaviconURLCache.insert(homePageURL)
self.homePageURLsWithNoFaviconURLCacheDirty = true
}
}
}
return
}
remainingFaviconURLs[homePageURL] = nil
postFaviconDidBecomeAvailableNotification(singleFaviconDownloader.faviconURL)
}
@objc func saveHomePageToFaviconURLCacheIfNeeded() {
if homePageToFaviconURLCacheDirty {
saveHomePageToFaviconURLCache()
}
}
@objc func saveHomePageURLsWithNoFaviconURLCacheIfNeeded() {
if homePageURLsWithNoFaviconURLCacheDirty {
saveHomePageURLsWithNoFaviconURLCache()
}
}
}
private extension FaviconDownloader {
static let localeForLowercasing = Locale(identifier: "en_US")
func findFaviconURLs(with homePageURL: String, _ completion: @escaping ([String]?) -> Void) {
guard let url = URL(unicodeString: homePageURL) else {
completion(nil)
return
}
FaviconURLFinder.findFaviconURLs(with: homePageURL) { (faviconURLs) in
guard var faviconURLs = faviconURLs else {
completion(nil)
return
}
var defaultFaviconURL: String? = nil
if let scheme = url.scheme, let host = url.host {
defaultFaviconURL = "\(scheme)://\(host)/favicon.ico".lowercased(with: FaviconDownloader.localeForLowercasing)
}
if let defaultFaviconURL = defaultFaviconURL {
faviconURLs.append(defaultFaviconURL)
}
completion(faviconURLs)
}
}
func faviconDownloader(withURL faviconURL: String, homePageURL: String?) -> SingleFaviconDownloader {
var firstTimeSeeingHomepageURL = false
if let homePageURL = homePageURL, self.homePageToFaviconURLCache[homePageURL] == nil {
self.homePageToFaviconURLCache[homePageURL] = faviconURL
self.homePageToFaviconURLCacheDirty = true
firstTimeSeeingHomepageURL = true
}
if let downloader = singleFaviconDownloaderCache[faviconURL] {
if firstTimeSeeingHomepageURL && !downloader.downloadFaviconIfNeeded() {
// This is to handle the scenario where we have different homepages, but the same favicon.
// This happens for Twitter and probably other sites like Blogger. Because the favicon
// is cached, we wouldn't send out a notification that it is now available unless we send
// it here.
postFaviconDidBecomeAvailableNotification(faviconURL)
}
return downloader
}
let downloader = SingleFaviconDownloader(faviconURL: faviconURL, homePageURL: homePageURL, diskCache: diskCache, queue: queue)
singleFaviconDownloaderCache[faviconURL] = downloader
return downloader
}
func postFaviconDidBecomeAvailableNotification(_ faviconURL: String) {
DispatchQueue.main.async {
let userInfo: [AnyHashable: Any] = [UserInfoKey.faviconURL: faviconURL]
NotificationCenter.default.post(name: .FaviconDidBecomeAvailable, object: self, userInfo: userInfo)
}
}
func loadHomePageToFaviconURLCache() {
let url = URL(fileURLWithPath: homePageToFaviconURLCachePath)
guard let data = try? Data(contentsOf: url) else {
return
}
let decoder = PropertyListDecoder()
homePageToFaviconURLCache = (try? decoder.decode([String: String].self, from: data)) ?? [String: String]()
}
func loadHomePageURLsWithNoFaviconURLCache() {
let url = URL(fileURLWithPath: homePageURLsWithNoFaviconURLCachePath)
guard let data = try? Data(contentsOf: url) else {
return
}
let decoder = PropertyListDecoder()
let decoded = (try? decoder.decode([String].self, from: data)) ?? [String]()
homePageURLsWithNoFaviconURLCache = Set(decoded)
}
func queueSaveHomePageToFaviconURLCacheIfNeeded() {
FaviconDownloader.saveQueue.add(self, #selector(saveHomePageToFaviconURLCacheIfNeeded))
}
func queueSaveHomePageURLsWithNoFaviconURLCacheIfNeeded() {
FaviconDownloader.saveQueue.add(self, #selector(saveHomePageURLsWithNoFaviconURLCacheIfNeeded))
}
func saveHomePageToFaviconURLCache() {
homePageToFaviconURLCacheDirty = false
let encoder = PropertyListEncoder()
encoder.outputFormat = .binary
let url = URL(fileURLWithPath: homePageToFaviconURLCachePath)
do {
let data = try encoder.encode(homePageToFaviconURLCache)
try data.write(to: url)
} catch {
assertionFailure(error.localizedDescription)
}
}
func saveHomePageURLsWithNoFaviconURLCache() {
homePageURLsWithNoFaviconURLCacheDirty = false
let encoder = PropertyListEncoder()
encoder.outputFormat = .binary
let url = URL(fileURLWithPath: homePageURLsWithNoFaviconURLCachePath)
do {
let data = try encoder.encode(Array(homePageURLsWithNoFaviconURLCache))
try data.write(to: url)
} catch {
assertionFailure(error.localizedDescription)
}
}
}