Add FeaturedImageDownloader.

Evergreen.xcodeproj/project.pbxproj

@@ -9,6 +9,8 @@
 /* Begin PBXBuildFile section */
 		8426118A1FCB67AA0086A189 /* FeedIconDownloader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 842611891FCB67AA0086A189 /* FeedIconDownloader.swift */; };
 		8426119E1FCB6ED40086A189 /* HTMLMetadataDownloader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8426119D1FCB6ED40086A189 /* HTMLMetadataDownloader.swift */; };
+		842611A01FCB72600086A189 /* FeaturedImageDownloader.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8426119F1FCB72600086A189 /* FeaturedImageDownloader.swift */; };
+		842611A21FCB769D0086A189 /* RSHTMLData+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = 842611A11FCB769D0086A189 /* RSHTMLData+Extension.swift */; };
 		842E45CE1ED8C308000A8B52 /* AppNotifications.swift in Sources */ = {isa = PBXBuildFile; fileRef = 842E45CD1ED8C308000A8B52 /* AppNotifications.swift */; };
 		842E45DD1ED8C54B000A8B52 /* Browser.swift in Sources */ = {isa = PBXBuildFile; fileRef = 842E45DC1ED8C54B000A8B52 /* Browser.swift */; };
 		842E45E31ED8C681000A8B52 /* KeyboardDelegateProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = 842E45E21ED8C681000A8B52 /* KeyboardDelegateProtocol.swift */; };
@@ -407,6 +409,8 @@
 /* Begin PBXFileReference section */
 		842611891FCB67AA0086A189 /* FeedIconDownloader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeedIconDownloader.swift; sourceTree = "<group>"; };
 		8426119D1FCB6ED40086A189 /* HTMLMetadataDownloader.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = HTMLMetadataDownloader.swift; sourceTree = "<group>"; };
+		8426119F1FCB72600086A189 /* FeaturedImageDownloader.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeaturedImageDownloader.swift; sourceTree = "<group>"; };
+		842611A11FCB769D0086A189 /* RSHTMLData+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "RSHTMLData+Extension.swift"; sourceTree = "<group>"; };
 		842E45CD1ED8C308000A8B52 /* AppNotifications.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = AppNotifications.swift; path = Evergreen/AppNotifications.swift; sourceTree = "<group>"; };
 		842E45DC1ED8C54B000A8B52 /* Browser.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; name = Browser.swift; path = Evergreen/Browser.swift; sourceTree = "<group>"; };
 		842E45E21ED8C681000A8B52 /* KeyboardDelegateProtocol.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = KeyboardDelegateProtocol.swift; sourceTree = "<group>"; };
@@ -581,6 +585,8 @@
 				845213221FCA5B10003B6E93 /* ImageDownloader.swift */,
 				84E850851FCB60CE0072EA88 /* AuthorAvatarDownloader.swift */,
 				842611891FCB67AA0086A189 /* FeedIconDownloader.swift */,
+				8426119F1FCB72600086A189 /* FeaturedImageDownloader.swift */,
+				842611A11FCB769D0086A189 /* RSHTMLData+Extension.swift */,
 			);
 			name = Images;
 			path = Evergreen/Images;
@@ -1372,6 +1378,7 @@
 				849A975C1ED9EB0D007D329B /* DefaultFeedsImporter.swift in Sources */,
 				849A97891ED9ECEF007D329B /* ArticleStyle.swift in Sources */,
 				84FF69B11FC3793300DC198E /* FaviconURLFinder.swift in Sources */,
+				842611A21FCB769D0086A189 /* RSHTMLData+Extension.swift in Sources */,
 				849A978A1ED9ECEF007D329B /* ArticleStylesManager.swift in Sources */,
 				849A97791ED9EC04007D329B /* TimelineStringUtilities.swift in Sources */,
 				84F204CE1FAACB660076E152 /* FeedListViewController.swift in Sources */,
@@ -1391,6 +1398,7 @@
 				849A978D1ED9EE4D007D329B /* FeedListWindowController.swift in Sources */,
 				849A97771ED9EC04007D329B /* TimelineCellData.swift in Sources */,
 				84B99C6B1FAE370B00ECDEDB /* FeedListFeed.swift in Sources */,
+				842611A01FCB72600086A189 /* FeaturedImageDownloader.swift in Sources */,
 				849A97781ED9EC04007D329B /* TimelineCellLayout.swift in Sources */,
 				849A976C1ED9EBC8007D329B /* TimelineTableRowView.swift in Sources */,
 				849A977B1ED9EC04007D329B /* UnreadIndicatorView.swift in Sources */,

Evergreen/AppDelegate.swift

@@ -24,6 +24,7 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations,
 	var faviconDownloader: FaviconDownloader!
 	var imageDownloader: ImageDownloader!
 	var authorAvatarDownloader: AuthorAvatarDownloader!
+	var feedIconDownloader: FeedIconDownloader!
 	var appName: String!
 	var pseudoFeeds = [PseudoFeed]()
 
@@ -144,7 +145,8 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSUserInterfaceValidations,
 		imageDownloader = ImageDownloader(folder: imagesFolder)
 
 		authorAvatarDownloader = AuthorAvatarDownloader(imageDownloader: imageDownloader)
-
+		feedIconDownloader = FeedIconDownloader(imageDownloader: imageDownloader)
+		
 		let todayFeed = SmartFeed(delegate: TodayFeedDelegate())
 		let unreadFeed = UnreadFeed()
 		let starredFeed = SmartFeed(delegate: StarredFeedDelegate())

Evergreen/Images/FeaturedImageDownloader.swift

@@ -0,0 +1,88 @@
+//
+//  FeaturedImageDownloader.swift
+//  Evergreen
+//
+//  Created by Brent Simmons on 11/26/17.
+//  Copyright © 2017 Ranchero Software. All rights reserved.
+//
+
+import Cocoa
+import Data
+import RSParser
+
+final class FeaturedImageDownloader {
+
+	private let imageDownloader: ImageDownloader
+	private var articleURLToFeaturedImageURLCache = [String: String]()
+	private var articleURLsWithNoFeaturedImage = Set<String>()
+
+	init(imageDownloader: ImageDownloader) {
+
+		self.imageDownloader = imageDownloader
+	}
+
+	func image(for article: Article) -> NSImage? {
+
+		if let url = article.imageURL {
+			return image(forFeaturedImageURL: url)
+		}
+		if let articleURL = article.url {
+			return image(forArticleURL: articleURL)
+		}
+		return nil
+	}
+
+	func image(forArticleURL articleURL: String) -> NSImage? {
+
+		if articleURLsWithNoFeaturedImage.contains(articleURL) {
+			return nil
+		}
+
+		if let featuredImageURL = cachedURL(for: articleURL) {
+			return image(forFeaturedImageURL: featuredImageURL)
+		}
+		findFeaturedImageURL(for: articleURL)
+		return nil
+	}
+
+	func image(forFeaturedImageURL featuredImageURL: String) -> NSImage? {
+
+		return imageDownloader.image(for: featuredImageURL)
+	}
+}
+
+private extension FeaturedImageDownloader {
+
+	func cachedURL(for articleURL: String) -> String? {
+
+		return articleURLToFeaturedImageURLCache[articleURL]
+	}
+
+	func cacheURL(for articleURL: String, _ featuredImageURL: String) {
+
+		articleURLsWithNoFeaturedImage.remove(articleURL)
+		articleURLToFeaturedImageURLCache[articleURL] = featuredImageURL
+	}
+
+	func findFeaturedImageURL(for articleURL: String) {
+
+		HTMLMetadataDownloader.downloadMetadata(for: articleURL) { (metadata) in
+
+			guard let metadata = metadata else {
+				return
+			}
+			self.pullFeaturedImageURL(from: metadata, articleURL: articleURL)
+		}
+	}
+
+	func pullFeaturedImageURL(from metadata: RSHTMLMetadata, articleURL: String) {
+
+		if let url = metadata.bestFeaturedImageURL() {
+			cacheURL(for: articleURL, url)
+			let _ = image(forFeaturedImageURL: url)
+			return
+		}
+
+		articleURLsWithNoFeaturedImage.insert(articleURL)
+	}
+}

Evergreen/Images/FeedIconDownloader.swift

@@ -15,6 +15,8 @@ public final class FeedIconDownloader {
 
 	private let imageDownloader: ImageDownloader
 	private var homePageToIconURLCache = [String: String]()
+	private var homePagesWithNoIconURL = Set<String>()
+	private var homePageDownloadsInProgress = Set<String>()
 
 	init(imageDownloader: ImageDownloader) {
 
@@ -36,6 +38,10 @@ public final class FeedIconDownloader {
 
 	func icon(forHomePageURL homePageURL: String) -> NSImage? {
 
+		if homePagesWithNoIconURL.contains(homePageURL) {
+			return nil
+		}
+
 		if let iconURL = cachedIconURL(for: homePageURL) {
 			return icon(forURL: iconURL)
 		}
@@ -59,14 +65,20 @@ private extension FeedIconDownloader {
 
 	func cacheIconURL(for homePageURL: String, _ iconURL: String) {
 
+		homePagesWithNoIconURL.remove(homePageURL)
 		homePageToIconURLCache[homePageURL] = iconURL
-		let _ = icon(forURL: iconURL)
 	}
 
 	func findIconURLForHomePageURL(_ homePageURL: String) {
 
+		guard !homePageDownloadsInProgress.contains(homePageURL) else {
+			return
+		}
+		homePageDownloadsInProgress.insert(homePageURL)
+
 		HTMLMetadataDownloader.downloadMetadata(for: homePageURL) { (metadata) in
 
+			self.homePageDownloadsInProgress.remove(homePageURL)
 			guard let metadata = metadata else {
 				return
 			}
@@ -76,34 +88,12 @@ private extension FeedIconDownloader {
 
 	func pullIconURL(from metadata: RSHTMLMetadata, homePageURL: String) {
 
-		if let openGraphImageURL = largestOpenGraphImageURL(from: metadata) {
-			cacheIconURL(for: homePageURL, openGraphImageURL)
+		if let url = metadata.bestWebsiteIconURL() {
+			cacheIconURL(for: homePageURL, url)
+			let _ = icon(forURL: url)
 			return
 		}
 
-		if let twitterImageURL = metadata.twitterProperties.imageURL {
-			cacheIconURL(for: homePageURL, twitterImageURL)
-		}
-	}
-
-	func largestOpenGraphImageURL(from metadata: RSHTMLMetadata) -> String? {
-
-		guard let openGraphImages = metadata.openGraphProperties?.images else {
-			return nil
-		}
-
-		var bestImage: RSHTMLOpenGraphImage? = nil
-
-		for image in openGraphImages {
-			if bestImage == nil {
-				bestImage = image
-				continue
-			}
-			if image.height > bestImage!.height && image.width > bestImage!.width {
-				bestImage = image
-			}
-		}
-
-		return bestImage?.secureURL ?? bestImage?.url
+		homePagesWithNoIconURL.insert(homePageURL)
 	}
 }

Evergreen/Images/RSHTMLData+Extension.swift

@@ -0,0 +1,64 @@
+//
+//  RSHTMLData+Extension.swift
+//  Evergreen
+//
+//  Created by Brent Simmons on 11/26/17.
+//  Copyright © 2017 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import RSParser
+
+extension RSHTMLMetadata {
+
+	func largestOpenGraphImageURL() -> String? {
+
+		guard let openGraphImages = openGraphProperties?.images, !openGraphImages.isEmpty else {
+			return nil
+		}
+
+		var bestImage: RSHTMLOpenGraphImage? = nil
+
+		for image in openGraphImages {
+			if bestImage == nil {
+				bestImage = image
+				continue
+			}
+			if image.height > bestImage!.height && image.width > bestImage!.width {
+				bestImage = image
+			}
+		}
+
+		guard let url = bestImage?.secureURL ?? bestImage?.url else {
+			return nil
+		}
+
+		// Bad ones we should ignore.
+		let badURLs = Set(["https://s0.wp.com/i/blank.jpg"])
+		guard !badURLs.contains(url) else {
+			return nil
+		}
+
+		return url
+	}
+
+	func bestWebsiteIconURL() -> String? {
+
+		// TODO: metadata icons — sometimes they’re large enough to use here.
+
+		if let openGraphImageURL = largestOpenGraphImageURL() {
+			return openGraphImageURL
+		}
+
+		return twitterProperties.imageURL
+	}
+
+	func bestFeaturedImageURL() -> String? {
+
+		if let openGraphImageURL = largestOpenGraphImageURL() {
+			return openGraphImageURL
+		}
+
+		return twitterProperties.imageURL
+	}
+}

Evergreen/MainWindow/Timeline/TimelineViewController.swift

@@ -443,11 +443,7 @@ extension TimelineViewController: NSTableViewDelegate {
 		// TODO: make Feed know about its authors.
 		// https://github.com/brentsimmons/Evergreen/issues/212
 
-		if let iconURL = feed.iconURL {
-			return appDelegate.imageDownloader.image(for: iconURL)
-		}
-
-		return nil
+		return appDelegate.feedIconDownloader.icon(for: feed)
 	}
 
 	private func avatarForAuthor(_ author: Author) -> NSImage? {