217 lines
8.5 KiB
Objective-C
217 lines
8.5 KiB
Objective-C
@import RSXML2;
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#import "FeedDownload.h"
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#import "FaviconDownload.h"
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#import "Download3rdParty.h"
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#import "Feed+Ext.h"
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#import "FeedMeta+Ext.h"
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#import "NSError+Ext.h"
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#import "NSURLRequest+Ext.h"
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@interface FeedDownload()
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@property (nonatomic, assign) BOOL respondToSelectFeed, respondToRedirect, respondToEnd;
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@property (nonatomic, weak) id<FeedDownloadDelegate> delegate;
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@property (nonatomic, strong) FeedDownloadBlock block;
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@property (nonatomic, weak) NSURLSessionTask *currentDownload;
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@property (nonatomic, assign) BOOL canceled;
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@property (nonatomic, assign) BOOL assertIsFeedURL; // prohibit processing of HTML data
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@property (nonatomic, strong) NSURLRequest *request;
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@property (nonatomic, strong) NSHTTPURLResponse* response;
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@property (nonatomic, strong) RSParsedFeed *xmlfeed;
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@property (nonatomic, strong) NSError *error;
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@property (nonatomic, strong) NSString *faviconURL;
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@end
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@implementation FeedDownload
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// ---------------------------------------------------------------
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// | MARK: - Class methods
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// ---------------------------------------------------------------
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/// @return New instance with plain @c url request.
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+ (instancetype)withURL:(NSString*)url {
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FeedDownload *this = [FeedDownload new];
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this.request = [NSURLRequest withURL:url];
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return this;
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}
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/// @return New instance using existing @c feed as template. Will reuse @c Etag and @c Last-modified headers.
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+ (instancetype)withFeed:(Feed*)feed forced:(BOOL)flag {
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FeedMeta *m = feed.meta;
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NSMutableURLRequest *req = [NSMutableURLRequest withURL:m.url];
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if (!flag) // any request that is not forced, is a background update
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req.networkServiceType = NSURLNetworkServiceTypeBackground;
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if (feed.articles.count > 0) { // dont use cache if feed is broken
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// Both fields should be send (if server provides both) RFC: https://tools.ietf.org/html/rfc7232#section-2.4
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if (m.etag.length > 0)
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[req setValue:[m.etag stringByReplacingOccurrencesOfString:@"-gzip" withString:@""] forHTTPHeaderField:@"If-None-Match"]; // ETag
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if (m.modified.length > 0)
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[req setValue:m.modified forHTTPHeaderField:@"If-Modified-Since"];
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}
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FeedDownload *this = [FeedDownload new];
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this.assertIsFeedURL = YES;
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this.request = req;
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return this;
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}
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// ---------------------------------------------------------------
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// | MARK: - Getter & Setter
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// ---------------------------------------------------------------
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/// Set delegate and check what methods are implemented.
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- (void)setDelegate:(id<FeedDownloadDelegate>)observer {
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_delegate = observer;
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_respondToSelectFeed = [observer respondsToSelector:@selector(feedDownload:selectFeedFromList:)];
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_respondToRedirect = [observer respondsToSelector:@selector(feedDownload:urlRedirected:)];
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_respondToEnd = [observer respondsToSelector:@selector(feedDownloadDidFinish:)];
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}
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/// @return Initialize @c FaviconDownload instance. Will reuse favicon url from HTML parsing.
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- (FaviconDownload*)faviconDownload {
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if (self.faviconURL.length > 0) // favicon url already found, nice job
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return [FaviconDownload withURL:self.faviconURL isImageURL:YES];
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NSString *url = self.xmlfeed.link; // does only work for status != 304
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if (!url) url = self.response.URL.absoluteString;
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return [FaviconDownload withURL:url isImageURL:NO];
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}
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// ---------------------------------------------------------------
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// | MARK: - Actions
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// ---------------------------------------------------------------
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/// Start download request and use @c delegate as callback notifier.
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- (instancetype)startWithDelegate:(id<FeedDownloadDelegate>)delegate {
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self.delegate = delegate;
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[self downloadSource:self.request];
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return self;
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}
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/// Start download request and use @c block as callback notifier.
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- (instancetype)startWithBlock:(nonnull FeedDownloadBlock)block {
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self.block = block;
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[self downloadSource:self.request];
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return self;
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}
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/// Cancel running download task without notice. Will notify neither @c delegate nor @c block
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- (void)cancel {
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self.canceled = YES;
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self.delegate = nil;
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self.block = nil;
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[self.currentDownload cancel];
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}
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/**
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Persist in memory object by copying all attributes to permanent core data storage.
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@param flag If @c YES then @c FeedGroup won't increase the error count for the feed.
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Feed will be scheduled as soon as the user reconnects to the internet.
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@return @c YES if downloaded feed contains at least one article. ( @c 304 returns @c NO )
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*/
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- (BOOL)copyValuesTo:(nonnull Feed*)feed ignoreError:(BOOL)flag {
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if (!flag && self.error) // Increase error count and schedule next update.
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[feed.meta setErrorAndPostponeSchedule];
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else if (self.response) // Update Etag & Last modified and schedule next update.
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[feed.meta setSucessfulWithResponse:self.response];
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else // Update URL but keep schedule (e.g., error while adding feed should auto-try once reconnected)
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[feed.meta setUrlIfChanged:self.request.URL.absoluteString];
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// If feed is broken indicate that feed will not be updated
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if (!self.xmlfeed || self.xmlfeed.articles.count == 0)
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return NO;
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// Else: Update stored articles and indicate that feed was updated
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[feed updateWithRSS:self.xmlfeed postUnreadCountChange:YES];
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return YES;
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}
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// ---------------------------------------------------------------
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// | MARK: - HTML Source Handling
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// ---------------------------------------------------------------
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/// Take the @c urlStr and run a download @c dataTask: on it. Auto-detect if data is HTML or feed.
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- (void)downloadSource:(NSURLRequest*)request {
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self.currentDownload = [request dataTask:^(NSData * _Nullable data, NSError * _Nullable error, NSHTTPURLResponse *response) {
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self.error = error;
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self.response = response;
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if (!data) { // data = nil if (error || 304)
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[self performSelectorOnMainThread:@selector(finishAndNotify) withObject:nil waitUntilDone:NO];
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return;
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}
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RSXMLData *xml = [[RSXMLData alloc] initWithData:data url:response.URL];
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if (!self.assertIsFeedURL && [xml.parserClass isHTMLParser])
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[self processXMLDataHTML:xml]; // HTML source handling
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else
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[self processXMLDataFeed:xml]; // XML source handling
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}];
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}
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/// The downloaded source seems to be HTML data, lets parse it with @c RSXML @c RSHTMLMetadataParser
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- (void)processXMLDataHTML:(RSXMLData*)xml {
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RSHTMLMetadataParser *parser = [RSHTMLMetadataParser parserWithXMLData:xml];
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[parser parseAsync:^(RSHTMLMetadata * _Nullable meta, NSError * _Nullable error) {
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NSString *feedURL = nil;
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if (error) {
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self.error = error;
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}
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else if (!meta || meta.feedLinks.count == 0) {
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if ([xml.url.host hasSuffix:@"youtube.com"])
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feedURL = [YouTubePlugin feedURL:xml.url data:xml.data];
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if (feedURL.length == 0)
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self.error = [NSError feedURLNotFound:xml.url];
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}
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else {
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feedURL = meta.feedLinks.firstObject.link;
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if (meta.feedLinks.count > 1 && self.respondToSelectFeed)
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feedURL = [self.delegate feedDownload:self selectFeedFromList:meta.feedLinks];
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if (!feedURL)
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self.error = [NSError canceledByUser];
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}
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// finalize HTML parsing
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if (self.error) {
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[self finishAndNotify];
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} else {
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self.assertIsFeedURL = YES;
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self.faviconURL = [FaviconDownload urlForMetadata:meta]; // re-use favicon url (if present)
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// Feeds like https://news.ycombinator.com/ return 503 if URLs are requested too rapidly
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//CFRunLoopRunInMode(kCFRunLoopDefaultMode, 1.0, false); // Non-blocking sleep (1s)
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[self downloadSource:[NSURLRequest withURL:feedURL]];
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}
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}];
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}
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// ---------------------------------------------------------------
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// | MARK: - XML Source Handling
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// ---------------------------------------------------------------
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/// The downloaded source seems to be proper feed data, lets parse it with @c RSXML @c RSFeedParser
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- (void)processXMLDataFeed:(RSXMLData*)xml {
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RSFeedParser *parser = [RSFeedParser parserWithXMLData:xml];
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parser.dontStopOnLowerAsciiBytes = YES;
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[parser parseAsync:^(RSParsedFeed * _Nullable parsedDocument, NSError * _Nullable error) {
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self.error = error;
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self.xmlfeed = parsedDocument;
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[self finishAndNotify];
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}];
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}
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/// Check if @c responseURL @c != @c requestURL
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- (void)checkRedirectAndNotify {
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NSString *responseURL = self.response.URL.absoluteString;
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if (responseURL.length > 0 && ![responseURL isEqualToString:self.request.URL.absoluteString]) {
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if (self.respondToRedirect) [self.delegate feedDownload:self urlRedirected:responseURL];
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}
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}
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/// Called when feed download finished or failed, but not if canceled. Will notify @c delegate .
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- (void)finishAndNotify {
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if (self.canceled)
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return;
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[self checkRedirectAndNotify];
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// notify observer
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if (self.respondToEnd) [self.delegate feedDownloadDidFinish:self];
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if (self.block) { self.block(self); self.block = nil; }
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}
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@end
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