Parser for YouTube URLs (channel, user, playlist)

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project does adhere to [Semantic Versioning](https://semver.org/spec/v2
 - Quick Look preview for OPML files
 - *Adding feed:* 5xx server errors have a reload button which will initiate a new download with the same URL
 - *Adding feed:* Empty feed title will automatically reuse title from xml file (even if xml title changes)
+- *Adding feed:* Parser for YouTube channel, user, and playlist URLs
 - *Adding feed:* `⌘R` will reload the same URL
 - *Settings, Feeds:* `⌘R` will reload the data source
 - *Settings, Feeds:* Refresh interval string localizations

baRSS.xcodeproj/project.pbxproj

@@ -26,6 +26,7 @@
 		5477D34E21233C62002BA27F /* FeedGroup+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 5477D34D21233C62002BA27F /* FeedGroup+Ext.m */; };
 		5478DF04225A7AE200D30C64 /* SettingsFeedsView.m in Sources */ = {isa = PBXBuildFile; fileRef = 5478DF03225A7AE200D30C64 /* SettingsFeedsView.m */; };
 		548C6D0A230C33DE003A1AAF /* NSURL+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 548C6D09230C33DE003A1AAF /* NSURL+Ext.m */; };
+		5491005D2331435E00858AE2 /* Download3rdParty.m in Sources */ = {isa = PBXBuildFile; fileRef = 5491005C2331435E00858AE2 /* Download3rdParty.m */; };
 		5496B511214D6275003ED4ED /* UserPrefs.m in Sources */ = {isa = PBXBuildFile; fileRef = 5496B510214D6275003ED4ED /* UserPrefs.m */; };
 		54A07A7F220E04CF00082C51 /* NSFetchRequest+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 54A07A7E220E04CF00082C51 /* NSFetchRequest+Ext.m */; };
 		54A07A82220E723D00082C51 /* MapUnreadTotal.m in Sources */ = {isa = PBXBuildFile; fileRef = 54A07A81220E723D00082C51 /* MapUnreadTotal.m */; };
@@ -135,6 +136,8 @@
 		54892F1D2235285700271CBA /* CHANGELOG.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = CHANGELOG.md; sourceTree = "<group>"; };
 		548C6D08230C33DE003A1AAF /* NSURL+Ext.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "NSURL+Ext.h"; sourceTree = "<group>"; };
 		548C6D09230C33DE003A1AAF /* NSURL+Ext.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "NSURL+Ext.m"; sourceTree = "<group>"; };
+		5491005B2331435E00858AE2 /* Download3rdParty.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = Download3rdParty.h; sourceTree = "<group>"; };
+		5491005C2331435E00858AE2 /* Download3rdParty.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = Download3rdParty.m; sourceTree = "<group>"; };
 		5496B50F214D6275003ED4ED /* UserPrefs.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = UserPrefs.h; sourceTree = "<group>"; };
 		5496B510214D6275003ED4ED /* UserPrefs.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = UserPrefs.m; sourceTree = "<group>"; };
 		54A07A7D220E04CF00082C51 /* NSFetchRequest+Ext.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "NSFetchRequest+Ext.h"; sourceTree = "<group>"; };
@@ -334,6 +337,8 @@
 			children = (
 				54ACC29321061E270020715F /* UpdateScheduler.h */,
 				54ACC29421061E270020715F /* UpdateScheduler.m */,
+				5491005B2331435E00858AE2 /* Download3rdParty.h */,
+				5491005C2331435E00858AE2 /* Download3rdParty.m */,
 				5450100E230E9C8600F0B165 /* FeedDownload.h */,
 				5450100F230E9C8600F0B165 /* FeedDownload.m */,
 				54B6F148231551B3002C94C9 /* FaviconDownload.h */,
@@ -586,6 +591,7 @@
 				546A6A2F22C585580034E806 /* SettingsAboutView.m in Sources */,
 				54B517072270E990006C1B29 /* NSView+Ext.m in Sources */,
 				54D857CE227C5785001BA1C8 /* RefreshStatisticsView.m in Sources */,
+				5491005D2331435E00858AE2 /* Download3rdParty.m in Sources */,
 				541C67C32255470B004D2CE6 /* SettingsAppearance.m in Sources */,
 				54B749DA2204A85C0022CC6D /* BarStatusItem.m in Sources */,
 				546FC43D21188AD5007CC3A3 /* SettingsFeeds.m in Sources */,

baRSS/Constants.h

@@ -28,6 +28,8 @@
 // TODO: Add support for media player? image feed?
 // <enclosure url="https://url.mp3" length="63274022" type="audio/mpeg" />
 // TODO: Disable 'update all' menu item during update?
+// TODO: HTML to Feed Generator.  https://github.com/RSS-Bridge/rss-bridge
+// TODO: SQlite instead of CoreData?  https://www.objc.io/issues/4-core-data/SQLite-instead-of-core-data/
 
 
 /// UTI type used for opml files

baRSS/Core Data/FeedGroup+Ext.m

@@ -22,9 +22,7 @@
 
 #import "FeedGroup+Ext.h"
 #import "Feed+Ext.h"
-#import "FeedMeta+Ext.h"
 #import "StoreCoordinator.h"
-#import "NSDate+Ext.h"
 
 @implementation FeedGroup (Ext)
 

baRSS/Feed Import/Download3rdParty.h

@@ -0,0 +1,30 @@
+//
+//  The MIT License (MIT)
+//  Copyright (c) 2019 Oleg Geier
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy of
+//  this software and associated documentation files (the "Software"), to deal in
+//  the Software without restriction, including without limitation the rights to
+//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+//  of the Software, and to permit persons to whom the Software is furnished to do
+//  so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+
+@import Cocoa;
+
+// TODO: Make plugins extensible? community extensions.
+@interface YouTubePlugin : NSObject
++ (NSString*)feedURL:(NSURL*)url;
++ (NSString*)videoImage:(NSString*)videoid;
++ (NSString*)videoImageHQ:(NSString*)videoid;
+@end

baRSS/Feed Import/Download3rdParty.m

@@ -0,0 +1,84 @@
+//
+//  The MIT License (MIT)
+//  Copyright (c) 2019 Oleg Geier
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy of
+//  this software and associated documentation files (the "Software"), to deal in
+//  the Software without restriction, including without limitation the rights to
+//  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+//  of the Software, and to permit persons to whom the Software is furnished to do
+//  so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in all
+//  copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//  SOFTWARE.
+
+#include "Download3rdParty.h"
+
+@implementation YouTubePlugin
+
+/**
+ Transforms YouTube URL to XML feed URL. @c https://www.youtube.com/{channel|user|playlist]}/{id}
+ 
+ @note
+ Some YouTube HTML pages contain the 'alternate' tag, others don't.
+ This method will only be executed, if no other feed url was found.
+
+ @return @c nil if @c url is not properly formatted, YouTube feed URL otherwise.
+ */
++ (NSString*)feedURL:(NSURL*)url {
+	if (![url.host hasSuffix:@"youtube.com"]) // 'youtu.be' & 'youtube-nocookie.com' will redirect
+		return nil;
+	// https://www.youtube.com/channel/[channel-id]
+	// https://www.youtube.com/user/[user-name]
+	// https://www.youtube.com/playlist?list=[playlist-id]
+#ifdef DEBUG
+	printf("resolving YouTube url:\n");
+	printf(" ↳ %s\n", url.absoluteString.UTF8String);
+#endif
+	NSString *found = nil;
+	NSArray<NSString*> *parts = url.pathComponents;
+	if (parts.count > 1) { // first path component is always '/'
+		static NSString* const ytBase = @"https://www.youtube.com/feeds/videos.xml";
+		NSString *type = parts[1];
+		if ([type isEqualToString:@"channel"]) {
+			if (parts.count > 2)
+				found = [ytBase stringByAppendingFormat:@"?channel_id=%@", parts[2]];
+		} else if ([type isEqualToString:@"user"]) {
+			if (parts.count > 2)
+				found = [ytBase stringByAppendingFormat:@"?user=%@", parts[2]];
+		} else if ([type isEqualToString:@"playlist"]) {
+			NSURLComponents *uc = [NSURLComponents componentsWithURL:url resolvingAgainstBaseURL:NO];
+			for (NSURLQueryItem *q in uc.queryItems) {
+				if ([q.name isEqualToString:@"list"]) {
+					found = [ytBase stringByAppendingFormat:@"?playlist_id=%@", q.value];
+					break;
+				}
+			}
+		}
+	}
+#ifdef DEBUG
+	printf(" ↳ %s\n", found ? found.UTF8String : "could not resolve!");
+#endif
+	return found; // may be nil
+}
+
+/// @return @c http://i.ytimg.com/vi/<videoid>/default.jpg
++ (NSString*)videoImage:(NSString*)videoid {
+	return [NSString stringWithFormat:@"http://i.ytimg.com/vi/%@/default.jpg", videoid];
+}
+
+/// @return @c http://i.ytimg.com/vi/<videoid>/hqdefault.jpg
++ (NSString*)videoImageHQ:(NSString*)videoid {
+	return [NSString stringWithFormat:@"http://i.ytimg.com/vi/%@/hqdefault.jpg", videoid];
+}
+
+@end
+

baRSS/Feed Import/FeedDownload.m

@@ -23,8 +23,10 @@
 @import RSXML2;
 #import "FeedDownload.h"
 #import "FaviconDownload.h"
+#import "Download3rdParty.h"
 #import "Feed+Ext.h"
 #import "FeedMeta+Ext.h"
+#import "NSError+Ext.h"
 #import "NSURLRequest+Ext.h"
 
 @interface FeedDownload()
@@ -122,6 +124,33 @@
 	[self.currentDownload cancel];
 }
 
+/**
+ Persist in memory object by copying all attributes to permanent core data storage.
+ 
+ @param flag If @c YES then @c FeedGroup won't increase the error count for the feed.
+ Feed will be scheduled as soon as the user reconnects to the internet.
+ @return @c YES if downloaded feed contains at least one article. ( @c 304 returns @c NO )
+ */
+- (BOOL)copyValuesTo:(nonnull Feed*)feed ignoreError:(BOOL)flag {
+	if (!flag && self.error) // Increase error count and schedule next update.
+		[feed.meta setErrorAndPostponeSchedule];
+	else if (self.response) // Update Etag & Last modified and schedule next update.
+		[feed.meta setSucessfulWithResponse:self.response];
+	else // Update URL but keep schedule (e.g., error while adding feed should auto-try once reconnected)
+		[feed.meta setUrlIfChanged:self.request.URL.absoluteString];
+	
+	// If feed is broken indicate that feed will not be updated
+	if (!self.xmlfeed || self.xmlfeed.articles.count == 0)
+		return NO;
+	// Else: Update stored articles and indicate that feed was updated
+	[feed updateWithRSS:self.xmlfeed postUnreadCountChange:YES];
+	return YES;
+}
+
+//  ---------------------------------------------------------------
+// |  MARK: - HTML Source Handling
+//  ---------------------------------------------------------------
+
 /// Take the @c urlStr and run a download @c dataTask: on it. Auto-detect if data is HTML or feed.
 - (void)downloadSource:(NSURLRequest*)request {
 	self.currentDownload = [request dataTask:^(NSData * _Nullable data, NSError * _Nullable error, NSHTTPURLResponse *response) {
@@ -133,9 +162,9 @@
 		}
 		RSXMLData *xml = [[RSXMLData alloc] initWithData:data url:response.URL];
 		if (!self.assertIsFeedURL && [xml.parserClass isHTMLParser])
-			[self processXMLDataHTML:xml];
+			[self processXMLDataHTML:xml]; // HTML source handling
 		else
-			[self processXMLDataFeed:xml];
+			[self processXMLDataFeed:xml]; // XML source handling
 	}];
 }
 
@@ -143,31 +172,40 @@
 - (void)processXMLDataHTML:(RSXMLData*)xml {
 	RSHTMLMetadataParser *parser = [RSHTMLMetadataParser parserWithXMLData:xml];
 	[parser parseAsync:^(RSHTMLMetadata * _Nullable meta, NSError * _Nullable error) {
+		NSString *feedURL = nil;
 		if (error) {
 			self.error = error;
-		} else if (!meta || meta.feedLinks.count == 0) {
+		}
-			self.error = RSXMLMakeErrorWrongParser(RSXMLErrorExpectingFeed, RSXMLErrorExpectingHTML, xml.url);
+		else if (!meta || meta.feedLinks.count == 0) {
+			if ([xml.url.host hasSuffix:@"youtube.com"])
+				feedURL = [YouTubePlugin feedURL:xml.url];
+			if (feedURL.length == 0)
+				self.error = [NSError feedURLNotFound:xml.url];
+		}
+		else {
+			feedURL = meta.feedLinks.firstObject.link;
+			if (meta.feedLinks.count > 1 && self.respondToSelectFeed)
+				feedURL = [self.delegate feedDownload:self selectFeedFromList:meta.feedLinks];
+			if (!feedURL)
+				self.error = [NSError canceledByUser];
+		}
+		// finalize HTML parsing
+		if (self.error) {
+			[self finishAndNotify];
 		} else {
-			self.faviconURL = [FaviconDownload urlForMetadata:meta]; // we can re-use favicon url if we find one
-			NSString *chosenURL = meta.feedLinks.firstObject.link;
-			if (self.respondToSelectFeed && meta.feedLinks.count > 1)
-				chosenURL = [self.delegate feedDownload:self selectFeedFromList:meta.feedLinks];
-			
-			if (chosenURL.length > 0) {
 			self.assertIsFeedURL = YES;
+			self.faviconURL = [FaviconDownload urlForMetadata:meta]; // re-use favicon url (if present)
 			// Feeds like https://news.ycombinator.com/ return 503 if URLs are requested too rapidly
 			//CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1.0, false); // Non-blocking sleep (1s)
-				[self downloadSource:[NSURLRequest withURL:chosenURL]];
+			[self downloadSource:[NSURLRequest withURL:feedURL]];
-				return;
-			} else { // User canceled operation, show appropriate error message
-				NSDictionary *info = @{ NSLocalizedDescriptionKey: NSLocalizedString(@"Operation canceled.", nil) };
-				self.error = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorCancelled userInfo:info];
 		}
-		}
-		[self finishAndNotify];
 	}];
 }
 
+//  ---------------------------------------------------------------
+// |  MARK: - XML Source Handling
+//  ---------------------------------------------------------------
+
 /// The downloaded source seems to be proper feed data, lets parse it with @c RSXML @c RSFeedParser
 - (void)processXMLDataFeed:(RSXMLData*)xml {
 	RSFeedParser *parser = [RSFeedParser parserWithXMLData:xml];
@@ -197,27 +235,4 @@
 	if (self.block) { self.block(self); self.block = nil; }
 }
 
-/**
- Persist in memory object by copying all attributes to permanent core data storage.
-
- @param flag If @c YES then @c FeedGroup won't increase the error count for the feed.
-             Feed will be scheduled as soon as the user reconnects to the internet.
- @return @c YES if downloaded feed contains at least one article. ( @c 304 returns @c NO )
- */
-- (BOOL)copyValuesTo:(nonnull Feed*)feed ignoreError:(BOOL)flag {
-	if (!flag && self.error) // Increase error count and schedule next update.
-		[feed.meta setErrorAndPostponeSchedule];
-	else if (self.response) // Update Etag & Last modified and schedule next update.
-		[feed.meta setSucessfulWithResponse:self.response];
-	else // Update URL but keep schedule (e.g., error while adding feed should auto-try once reconnected)
-		[feed.meta setUrlIfChanged:self.request.URL.absoluteString];
-	
-	// If feed is broken indicate that feed will not be updated
-	if (!self.xmlfeed || self.xmlfeed.articles.count == 0)
-		return NO;
-	// Else: Update stored articles and indicate that feed was updated
-	[feed updateWithRSS:self.xmlfeed postUnreadCountChange:YES];
-	return YES;
-}
-
 @end

baRSS/Helper/NSError+Ext.h

@@ -23,5 +23,8 @@
 @import Cocoa;
 
 @interface NSError (Ext)
+// Generators
 + (instancetype)statusCode:(NSInteger)code reason:(nullable NSString*)reason;
++ (instancetype)canceledByUser;
++ (instancetype)feedURLNotFound:(NSURL*)url;
 @end

baRSS/Helper/NSError+Ext.m

@@ -20,6 +20,7 @@
 //  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 //  SOFTWARE.
 
+@import RSXML2.RSXMLError;
 #import "NSError+Ext.h"
 
 @implementation NSError (Ext)
@@ -98,6 +99,10 @@ static const char* CodeDescription(NSInteger code) {
 	return "Unknown";
 }
 
+//  ---------------------------------------------------------------
+// |  MARK: - Generators
+//  ---------------------------------------------------------------
+
 /// Generate @c NSError from HTTP status code. E.g., @c code @c = @c 404 will return "404 Not Found".
 + (instancetype)statusCode:(NSInteger)code reason:(nullable NSString*)reason {
 	NSMutableDictionary *info = [NSMutableDictionary dictionaryWithCapacity:2];
@@ -107,7 +112,18 @@ static const char* CodeDescription(NSInteger code) {
 	NSInteger errCode = NSURLErrorUnknown;
 	if (code < 500) { if (code >= 400) errCode = NSURLErrorResourceUnavailable; }
 	else if (code < 600) errCode = NSURLErrorBadServerResponse;
-	return [NSError errorWithDomain:NSURLErrorDomain code:errCode userInfo:info];
+	return [self errorWithDomain:NSURLErrorDomain code:errCode userInfo:info];
+}
+
+/// Generate @c NSError for user canceled operation. With title "Operation canceled.".
++ (instancetype)canceledByUser {
+	NSDictionary *info = @{ NSLocalizedDescriptionKey: NSLocalizedString(@"Operation canceled.", nil) };
+	return [self errorWithDomain:NSURLErrorDomain code:NSURLErrorCancelled userInfo:info];
+}
+
+/// Generate @c NSError for webpages that don't contain feed urls.
++ (instancetype)feedURLNotFound:(NSURL*)url {
+	return RSXMLMakeErrorWrongParser(RSXMLErrorExpectingFeed, RSXMLErrorExpectingHTML, url);
 }
 
 @end

baRSS/Info.plist

@@ -70,7 +70,7 @@
 		</dict>
 	</array>
 	<key>CFBundleVersion</key>
-	<string>13207</string>
+	<string>13404</string>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.news</string>
 	<key>LSMinimumSystemVersion</key>

baRSS/Preferences/Feeds Tab/SettingsFeedsView.m

@@ -23,7 +23,6 @@
 #import "SettingsFeedsView.h"
 #import "StoreCoordinator.h"
 #import "FeedGroup+Ext.h"
-#import "FeedMeta+Ext.h"
 #import "DrawImage.h"
 #import "SettingsFeeds.h"
 #import "NSDate+Ext.h"