Propagate 5xx server error to user + reload button. Closes #5

CHANGELOG.md

@@ -6,9 +6,16 @@ and this project does NOT adhere to [Semantic Versioning](https://semver.org/spe
 
 
 ## [Unreleased]
+### Added
+- Show users any 5xx server error response and extracted failure reason
+- 5xx server errors have a reload button which will initiate a new download with the same URL
+- Adding feed: Cmd+R will reload the same URL
+- Settings, Feeds: Cmd+R will reload the data source 
+
 ### Fixed
 - Changed error message text when user cancels creation of new feed item
 - Comparing existing articles with nonexistent guid and link
+- Adding feed: If URLs can't be resolved in the first run (5xx error), try a second time. E.g., 'Done' click (issue: #5)  
 
 ### Changed
 - Interface builder files replaced with code equivalent

baRSS/AppHook.m

@@ -187,6 +187,7 @@ static NSEventModifierFlags fnKeyFlags = NSEventModifierFlagShift | NSEventModif
 				case 'a': if ([self sendAction:@selector(selectAll:) to:nil from:self]) return; break;
 				case 'q': if ([self sendAction:@selector(performClose:) to:nil from:self]) return; break;
 				case 'w': if ([self sendAction:@selector(performClose:) to:nil from:self]) return; break;
+				case 'r': if ([self sendAction:@selector(reloadData) to:nil from:self]) return; break;
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wundeclared-selector"
 				case 'z': if ([self sendAction:@selector(undo:) to:nil from:self]) return; break;

baRSS/Helper/FeedDownload.m

@@ -201,12 +201,32 @@ static BOOL _nextUpdateIsForced = NO;
 + (void)asyncRequest:(NSURLRequest*)request block:(nonnull void(^)(NSData * _Nullable data, NSError * _Nullable error, NSHTTPURLResponse *response))block {
 	[[[self nonCachingSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
 		NSHTTPURLResponse* httpResponse = (NSHTTPURLResponse*)response;
-		if (error || [httpResponse statusCode] == 304)
+		NSInteger status = [httpResponse statusCode];
+		if (error || status == 304) { // 304 Not Modified
 			data = nil;
+		} else if (status >= 500 && status < 600) { // 5xx Server Error
+			NSString *reason = [NSString stringWithFormat:NSLocalizedString(@"Server HTTP error %ld.\n––––\n%@", nil),
+								status, [self extractReadableHTML:data]];
+			error = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorBadServerResponse userInfo:@{NSLocalizedDescriptionKey: reason}];
+			data = nil;
+		}
 		block(data, error, httpResponse); // if status == 304, data & error nil
 	}] resume];
 }
 
+/// Helper method to extract readable text from HTML
++ (NSString*)extractReadableHTML:(NSData*)data {
+	NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
+	// replace all <tags> with (presumably) non-used character
+	str = [[NSRegularExpression regularExpressionWithPattern:@"<[^>]*>\\s*" options:kNilOptions error:nil]
+		   stringByReplacingMatchesInString:str options:kNilOptions range:NSMakeRange(0, str.length) withTemplate:@"◊"];
+	// then replace multiple occurences of that character with a single new line
+	str = [[NSRegularExpression regularExpressionWithPattern:@"◊+" options:kNilOptions error:nil]
+		   stringByReplacingMatchesInString:str options:kNilOptions range:NSMakeRange(0, str.length) withTemplate:@"\n"];
+	// finally trim whitespace at start and end
+	return [str stringByTrimmingCharactersInSet: NSCharacterSet.whitespaceAndNewlineCharacterSet];
+}
+
 
 #pragma mark - Download RSS Feed -
 
@@ -266,9 +286,9 @@ static BOOL _nextUpdateIsForced = NO;
 		dispatch_sync(dispatch_get_main_queue(), ^{ // sync! (thread is already in background)
 			chosenURL = askUser(parsedMeta);
 		});
-		if (!chosenURL || chosenURL.length == 0) {
-			// User canceled operation, show appropriate error message
-			*err = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorCancelled userInfo:@{NSLocalizedDescriptionKey: NSLocalizedString(@"Operation canceled.", nil)}];
+		if (!chosenURL || chosenURL.length == 0) { // User canceled operation, show appropriate error message
+			NSString *reason = NSLocalizedString(@"Operation canceled.", nil);
+			*err = [NSError errorWithDomain:NSURLErrorDomain code:NSURLErrorCancelled userInfo:@{NSLocalizedDescriptionKey: reason}];
 			return NO;
 		}
 		[self parseFeedRequest:[self newRequestURL:chosenURL] xmlBlock:nil feedBlock:block];

baRSS/Helper/NSView+Ext.h

@@ -56,7 +56,7 @@ NS_INLINE CGFloat YFromTop(NSView *view) { return NSHeight(view.superview.frame)
 // UI: Buttons
 + (NSButton*)button:(NSString*)text;
 + (NSButton*)buttonImageSquare:(nonnull NSImageName)name;
-+ (NSButton*)buttonIcon:(NSImage*)img size:(CGFloat)size;
++ (NSButton*)buttonIcon:(nonnull NSImageName)name size:(CGFloat)size;
 + (NSButton*)inlineButton:(NSString*)text;
 + (NSPopUpButton*)popupButton:(CGFloat)w;
 // UI: Others

baRSS/Helper/NSView+Ext.m

@@ -87,11 +87,11 @@
 }
 
 /// Create pure image button with no border.
-+ (NSButton*)buttonIcon:(NSImage*)img size:(CGFloat)size {
++ (NSButton*)buttonIcon:(nonnull NSImageName)name size:(CGFloat)size {
 	NSButton *btn = [[NSButton alloc] initWithFrame: NSMakeRect(0, 0, size, size)];
 	btn.bezelStyle = NSBezelStyleRounded;
 	btn.bordered = NO;
-	btn.image = img;
+	btn.image = [NSImage imageNamed:name];
 	return btn;
 }
 
@@ -271,6 +271,8 @@
 	self.toolTip = tt;
 	if (self.accessibilityLabel.length == 0)
 		self.accessibilityLabel = tt;
+	else
+		self.accessibilityValueDescription = tt;
 	return self;
 }
 

baRSS/Info.plist

@@ -32,7 +32,7 @@
 		</dict>
 	</array>
 	<key>CFBundleVersion</key>
-	<string>7539</string>
+	<string>7702</string>
 	<key>LSMinimumSystemVersion</key>
 	<string>$(MACOSX_DEPLOYMENT_TARGET)</string>
 	<key>LSUIElement</key>

baRSS/Preferences/Feeds Tab/ModalFeedEdit.m

@@ -146,6 +146,7 @@
 	self.httpEtag = nil;
 	self.httpDate = nil;
 	self.faviconURL = nil;
+	self.previousURL = self.view.url.stringValue;
 }
 
 /**
@@ -179,8 +180,11 @@
  @return Either URL string or @c nil if user canceled the selection.
  */
 - (NSString*)letUserChooseXmlUrlFromList:(NSArray<RSHTMLMetadataFeedLink*> *)list {
-	if (list.count == 1) // nothing to choose
+	if (list.count == 1) { // nothing to choose
+		// Feeds like https://news.ycombinator.com/ return 503 if URLs are requested too rapidly
+		//CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1.0, false); // Non-blocking sleep (1s)
 		return list.firstObject.link;
+	}
 	NSMenu *menu = [[NSMenu alloc] initWithTitle:NSLocalizedString(@"Choose feed menu", nil)];
 	menu.autoenablesItems = NO;
 	for (RSHTMLMetadataFeedLink *fl in list) {
@@ -203,11 +207,19 @@
 - (void)postDownload:(NSString*)responseURL {
 	if (self.modalSheet.didCloseAndCancel)
 		return;
+	
+	BOOL hasError = (self.feedError != nil);
 	// 1. Stop spinner animation for name field. (keep spinner for URL running until favicon downloaded)
 	[self.view.spinnerName stopAnimation:nil];
 	// 2. If URL was redirected, replace original text field value with new one. (e.g., https redirect)
 	if (responseURL.length > 0 && ![responseURL isEqualToString:self.previousURL]) {
+		if (!hasError) {
+			// If the url has changed and there is an error:
+			// This probably means the feed URL was resolved, but the successive download returned 5xx error.
+			// Presumably to prevent site crawlers accessing many pages in quick succession. (delay of 1s does help)
+			// By not setting previousURL, a second hit on the 'Done' button will retry the resolved URL again.
 			self.previousURL = responseURL;
+		}
 		self.view.url.stringValue = responseURL;
 	}
 	// 3. Copy parsed feed title to text field. (only if user hasn't set anything else yet)
@@ -218,7 +230,6 @@
 	// TODO: user preference to automatically select refresh interval (selection: None,min,max,avg,median)
 	[self statsForDownloadObject];
 	// 4. Continue with favicon download (or finish with error)
-	BOOL hasError = (self.feedError != nil);
 	self.view.favicon.hidden = hasError;
 	self.view.warningButton.hidden = !hasError;
 	if (hasError) {
@@ -305,7 +316,6 @@
 - (void)controlTextDidEndEditing:(NSNotification *)obj {
 	if (obj.object == self.view.url) {
 		if (![self.previousURL isEqualToString:self.view.url.stringValue]) {
-			self.previousURL = self.view.url.stringValue;
 			[self downloadRSS];
 		}
 	}
@@ -316,15 +326,26 @@
 	if (!self.feedError)
 		return;
 	
+	// show reload button if server is temporarily offline (any 5xx server error)
+	BOOL serverError = (self.feedError.domain == NSURLErrorDomain && self.feedError.code == NSURLErrorBadServerResponse);
+	self.view.warningReload.hidden = !serverError;
+	
+	// set error description as text
 	self.view.warningText.objectValue = self.feedError.localizedDescription;
 	NSSize newSize = self.view.warningText.fittingSize; // width is limited by the textfield's preferred width
 	newSize.width += 2 * self.view.warningText.frame.origin.x; // the padding
 	newSize.height += 2 * self.view.warningText.frame.origin.y;
 	
+	// apply fitting size and display
 	self.view.warningPopover.contentSize = newSize;
 	[self.view.warningPopover showRelativeToRect:sender.bounds ofView:sender preferredEdge:NSRectEdgeMinY];
 }
 
+/// Either hit by Cmd+R or reload button inside warning popover error description
+- (void)reloadData {
+	[self downloadRSS];
+}
+
 @end
 
 

baRSS/Preferences/Feeds Tab/ModalFeedEditView.h

@@ -38,6 +38,7 @@
 @property (weak) IBOutlet NSButton *warningButton;
 @property NSPopover *warningPopover;
 @property (weak) IBOutlet NSTextField *warningText;
+@property (weak) IBOutlet NSButton *warningReload;
 
 - (instancetype)initWithController:(ModalFeedEdit*)controller NS_DESIGNATED_INITIALIZER;
 - (instancetype)initWithFrame:(NSRect)frameRect NS_UNAVAILABLE;

baRSS/Preferences/Feeds Tab/ModalFeedEditView.m

@@ -47,10 +47,7 @@
 	self.url = [[[NSView inputField:@"https://example.org/feed.rss" width:0] placeIn:self x:x yTop:0] sizeToRight:PAD_S + 18];
 	self.spinnerURL = [[NSView activitySpinner] placeIn:self xRight:1 yTop:2.5];
 	self.favicon = [[[NSView imageView:nil size:18] tooltip:NSLocalizedString(@"Favicon", nil)] placeIn:self xRight:0 yTop:1.5];
-	NSTextField *errorDesc = [self warningPopoverContentView];
-	self.warningPopover = [self warningPopoverControllerWith:errorDesc];
-	self.warningText = errorDesc; // after added to parent view, otherwise will be released immediatelly (weak ivar)
-	self.warningButton = [[[[NSView buttonIcon:[NSImage imageNamed:NSImageNameCaution] size:18] action:@selector(didClickWarningButton:) target:nil] // up the responder chain
+	self.warningButton = [[[[NSView buttonIcon:NSImageNameCaution size:18] action:@selector(didClickWarningButton:) target:nil] // up the responder chain
 						   tooltip:NSLocalizedString(@"Click here to show failure reason", nil)]
 						  placeIn:self xRight:0 yTop:1.5];
 	// 2. row
@@ -61,34 +58,39 @@
 	self.refreshUnit = [[NSView popupButton:120] placeIn:self x:NSMaxX(self.refreshNum.frame) + PAD_M yTop:2*rowHeight];
 	
 	// initial state
+	self.url.accessibilityLabel = lbls[0];
+	self.name.accessibilityLabel = lbls[1];
+	self.refreshNum.accessibilityLabel = NSLocalizedString(@"Refresh interval", nil);
 	self.url.delegate = controller;
 	self.warningButton.hidden = YES;
 	self.refreshNum.formatter = [StrictUIntFormatter new]; // see below ...
-	//[self.warningButton.cell setHighlightsBy:(error ? NSContentsCellMask : NSNoCellMask)];
+	[self prepareWarningPopover];
 	return self;
 }
 
-/// User visible error description text (after click on warning button)
-- (NSTextField*)warningPopoverContentView {
-	NSTextField *txt = [[[NSView label:@""] selectable] sizableWidthAndHeight];
-	[txt setFrameSize: NSMakeSize(300, 100)];
-	txt.lineBreakMode = NSLineBreakByWordWrapping;
-	txt.maximumNumberOfLines = 7;
-	return txt;
-}
-
-/// Prepare popover controller to display download errors
-- (NSPopover*)warningPopoverControllerWith:(NSTextField*)content {
+/// Prepare popover controller to display errors during download
+- (void)prepareWarningPopover {
 	NSPopover *pop = [[NSPopover alloc] init];
 	pop.behavior = NSPopoverBehaviorTransient;
 	pop.contentViewController = [[NSViewController alloc] init];
 	
-	pop.contentViewController.view = [[NSView alloc] initWithFrame:content.frame];
-	[pop.contentViewController.view addSubview:content];
+	NSView *content = [[NSView alloc] initWithFrame:NSMakeRect(0, 0, 300, 100)];
+	pop.contentViewController.view = content;
 	
-	content.frame = NSInsetRect(content.frame, 4, 2);
-	content.preferredMaxLayoutWidth = NSWidth(content.frame);
-	return pop;
+	// User visible error description text (after click on warning button)
+	NSTextField *txt = [[[NSView label:@""] selectable] sizableWidthAndHeight];
+	txt.frame = NSInsetRect(content.frame, 4, 2);
+	txt.preferredMaxLayoutWidth = NSWidth(txt.frame);
+	txt.lineBreakMode = NSLineBreakByWordWrapping;
+	txt.maximumNumberOfLines = 7;
+	[content addSubview:txt];
+	
+	self.warningPopover = pop;
+	self.warningText = txt;
+	// Reload button is only visible on 5xx server error (right of ––––)
+	self.warningReload = [[[[NSView buttonIcon:NSImageNameRefreshTemplate size:16] placeIn:content x:35 yTop:21]
+						   tooltip:NSLocalizedString(@"Retry download (Cmd+R)", nil)]
+						  action:@selector(reloadData) target:nil]; // up the responder chain
 }
 
 @end

baRSS/Preferences/Feeds Tab/SettingsFeedsView.m

@@ -134,7 +134,7 @@
  */
 - (CGFloat)generateButtons {
 	NSButton *add = [[NSView buttonImageSquare:NSImageNameAddTemplate] tooltip:NSLocalizedString(@"Add new item", nil)];
-	NSButton *del = [[NSView buttonImageSquare:NSImageNameRemoveTemplate] tooltip:NSLocalizedString(@"Delete selected item(s)", nil)];
+	NSButton *del = [[NSView buttonImageSquare:NSImageNameRemoveTemplate] tooltip:NSLocalizedString(@"Delete selected items", nil)];
 	NSButton *share = [[NSView buttonImageSquare:NSImageNameShareTemplate] tooltip:NSLocalizedString(@"Import or export data", nil)];
 	
 	[self button:add copyActions:3 to:5];