Added the ability to resume large file downloads

@@ -50,7 +50,7 @@
 	success = ([[request responseString] isEqualToString:[NSString stringWithFormat:@"post_var: %@\r\npost_var2: %@\r\npost_var3: %@\r\nfile_name: %@\r\nfile_size: %hu",@"foo",d,v,@"file",size]]);
 	GHAssertTrue(success,@"Failed to upload the correct data (using NSData)");	
 }
- 
+
 
 
 @end

@@ -179,6 +179,8 @@ typedef enum _ASINetworkErrorType {
 	
 	NSStringEncoding defaultResponseEncoding;
 	NSStringEncoding responseEncoding;
+	
+	BOOL allowResumeForFileDownloads;
 }
 
 #pragma mark init / dealloc
@@ -311,7 +313,7 @@ typedef enum _ASINetworkErrorType {
 @property (assign) BOOL useKeychainPersistance;
 @property (assign) BOOL useSessionPersistance;
 @property (retain) NSString *downloadDestinationPath;
-@property (retain,readonly) NSString *temporaryFileDownloadPath;
+@property (retain) NSString *temporaryFileDownloadPath;
 @property (assign) SEL didFinishSelector;
 @property (assign) SEL didFailSelector;
 @property (retain,readonly) NSString *authenticationRealm;
@@ -339,4 +341,5 @@ typedef enum _ASINetworkErrorType {
 @property (assign) NSStringEncoding defaultResponseEncoding;
 @property (assign) NSStringEncoding responseEncoding;
 @property (assign) BOOL allowCompressedResponse;
+@property (assign) BOOL allowResumeForFileDownloads;
 @end

@@ -81,9 +81,11 @@ static NSError *ASIUnableToCreateRequestError;
 	[self setUploadBufferSize:0];
 	[self setResponseHeaders:nil];
 	[self setTimeOutSeconds:10];
+	[self setAllowResumeForFileDownloads:NO];
 	[self setUseKeychainPersistance:NO];
 	[self setUseSessionPersistance:YES];
 	[self setUseCookiePersistance:YES];
+	[self setRawResponseData:nil];
 	[self setRequestCookies:[[[NSMutableArray alloc] init] autorelease]];
 	[self setDidFinishSelector:@selector(requestFinished:)];
 	[self setDidFailSelector:@selector(requestFailed:)];
@@ -272,6 +274,12 @@ static NSError *ASIUnableToCreateRequestError;
 		[self addRequestHeader:@"Accept-Encoding" value:@"gzip"];
 	}
 	
+	// Should this request resume an existing download?
+	if ([self allowResumeForFileDownloads] && [self downloadDestinationPath] && [self temporaryFileDownloadPath] && [[NSFileManager defaultManager] fileExistsAtPath:[self temporaryFileDownloadPath]]) {
+		unsigned long long downloadedSoFar = [[[NSFileManager defaultManager] fileAttributesAtPath:[self temporaryFileDownloadPath] traverseLink:NO] fileSize];
+		[self addRequestHeader:@"Range" value:[NSString stringWithFormat:@"bytes=%llu-",downloadedSoFar]];
+	}
+	
 	// Add custom headers
 	NSDictionary *headers;
 	
@@ -322,8 +330,9 @@ static NSError *ASIUnableToCreateRequestError;
 		contentLength = 0;
 	}
 	[self setResponseHeaders:nil];
-    [self setRawResponseData:[[[NSMutableData alloc] init] autorelease]];
-    
+	if (![self downloadDestinationPath]) {
+		[self setRawResponseData:[[[NSMutableData alloc] init] autorelease]];
+    }
     // Create the stream for the request.
     readStream = CFReadStreamCreateForStreamedHTTPRequest(kCFAllocatorDefault, request,readStream);
     if (!readStream) {
@@ -431,10 +440,14 @@ static NSError *ASIUnableToCreateRequestError;
     if (rawResponseData) {
 		[self setRawResponseData:nil];
 	
-	// If we were downloading to a file, let's remove it
+	// If we were downloading to a file
 	} else if (temporaryFileDownloadPath) {
 		[outputStream close];
-		[[NSFileManager defaultManager] removeItemAtPath:temporaryFileDownloadPath error:NULL];
+		
+		// If we haven't said we might want to resume, let's remove the temporary file too
+		if (![self allowResumeForFileDownloads]) {
+			[[NSFileManager defaultManager] removeItemAtPath:temporaryFileDownloadPath error:NULL];
+		}
 	}
 	
 	[self setResponseHeaders:nil];
@@ -755,6 +768,7 @@ static NSError *ASIUnableToCreateRequestError;
 	BOOL isAuthenticationChallenge = NO;
 	CFHTTPMessageRef headers = (CFHTTPMessageRef)CFReadStreamCopyProperty(readStream, kCFStreamPropertyHTTPResponseHeader);
 	if (CFHTTPMessageIsHeaderComplete(headers)) {
+		
 		CFDictionaryRef headerFields = CFHTTPMessageCopyAllHeaderFields(headers);
 		[self setResponseHeaders:(NSDictionary *)headerFields];
 		CFRelease(headerFields);
@@ -1083,9 +1097,14 @@ static NSError *ASIUnableToCreateRequestError;
 		// Are we downloading to a file?
 		if (downloadDestinationPath) {
 			if (!outputStream) {
-				[temporaryFileDownloadPath release];
-				temporaryFileDownloadPath = [[NSTemporaryDirectory() stringByAppendingPathComponent:[[NSProcessInfo processInfo] globallyUniqueString]] retain];
-				outputStream = [[NSOutputStream alloc] initToFileAtPath:temporaryFileDownloadPath append:NO];
+				BOOL append = NO;
+				if (![self temporaryFileDownloadPath]) {
+					[self setTemporaryFileDownloadPath:[NSTemporaryDirectory() stringByAppendingPathComponent:[[NSProcessInfo processInfo] globallyUniqueString]]];
+				} else if ([self allowResumeForFileDownloads]) {
+					append = YES;
+				}
+				
+				outputStream = [[NSOutputStream alloc] initToFileAtPath:temporaryFileDownloadPath append:append];
 				[outputStream open];
 			}
 			[outputStream write:buffer maxLength:bytesRead];
@@ -1108,7 +1127,7 @@ static NSError *ASIUnableToCreateRequestError;
 	}
 	[progressLock lock];	
 	complete = YES;
-	[self updateProgressIndicators];	
+	[self updateProgressIndicators];
 	
     if (readStream) {
         CFReadStreamClose(readStream);
@@ -1442,4 +1461,5 @@ static NSError *ASIUnableToCreateRequestError;
 @synthesize defaultResponseEncoding;
 @synthesize responseEncoding;
 @synthesize allowCompressedResponse;
+@synthesize allowResumeForFileDownloads;
 @end

@@ -504,5 +504,29 @@
 }
 
 
+- (void)testPartialFetch
+{
+	NSString *downloadPath = [[[[NSBundle mainBundle] bundlePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"testfile.txt"];
+	NSString *tempPath = [[[[NSBundle mainBundle] bundlePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"tempfile.txt"];
+	NSString *partialContent = @"This file should be exactly 163 bytes long when encoded as UTF8, Unix line breaks with no BOM.\n";
+	[partialContent writeToFile:tempPath atomically:NO encoding:NSASCIIStringEncoding error:nil];
+	
+	NSURL *url = [[[NSURL alloc] initWithString:@"http://allseeing-i.com/ASIHTTPRequest/Tests/test_partial_download.txt"] autorelease];
+	ASIHTTPRequest *request = [[[ASIHTTPRequest alloc] initWithURL:url] autorelease];
+	[request setDownloadDestinationPath:downloadPath];
+	[request setTemporaryFileDownloadPath:tempPath];
+	[request setAllowResumeForFileDownloads:YES];
+	[request start];
+	
+	BOOL success = ([request contentLength] == 68);
+	GHAssertTrue(success,@"Failed to download a segment of the data");
+	
+	NSString *content = [NSString stringWithContentsOfFile:downloadPath];
+	
+	NSString *newPartialContent = [content substringFromIndex:95];
+	success = ([newPartialContent isEqualToString:@"This is the content we ought to be getting if we start from byte 95."]);
+	GHAssertTrue(success,@"Failed to append the correct data to the end of the file?");
+	
+}
 
 @end

@@ -139,6 +139,13 @@
 			if ([[request requestMethod] isEqualToString:@"GET"]) {
 				ASIHTTPRequest *HEADRequest = [[[ASIHTTPRequest alloc] initWithURL:[request url]] autorelease];
 				[HEADRequest setMainRequest:request];
+				
+				//If we're downloading to a file, and we already have a partial download to start from
+				if ([request allowResumeForFileDownloads] && [request downloadDestinationPath] && [request temporaryFileDownloadPath] && [[NSFileManager defaultManager] fileExistsAtPath:[request temporaryFileDownloadPath]]) {
+					unsigned long long downloadedSoFar = [[[NSFileManager defaultManager] fileAttributesAtPath:[request temporaryFileDownloadPath] traverseLink:NO] fileSize];
+					[HEADRequest addRequestHeader:@"Range" value:[NSString stringWithFormat:@"bytes=%llu-",downloadedSoFar]];
+				}
+				
 				[self addHEADOperation:HEADRequest];
 				
 				//Tell the request not to reset the progress indicator when it gets a content-length, as we will get the length from the HEAD request

@@ -25,6 +25,7 @@
 - (void)testProgress;
 - (void)testProgressWithAuthentication;
 - (void)testWithNoListener;
+- (void)testPartialResume;
 
 - (void)setProgress:(float)newProgress;
 

@@ -303,5 +303,73 @@ static CFStringRef ASIHTTPRequestTestsRunMode = CFSTR("ASIHTTPRequestTestsRunMod
 	[networkQueue release];
 }
 
+- (void)testPartialResume
+{
+	complete = NO;
+	
+	NSString *temporaryPath = [[[[NSBundle mainBundle] bundlePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"MemexTrails_1.0b1.zip.download"];
+	if ([[NSFileManager defaultManager] fileExistsAtPath:temporaryPath]) {
+		[[NSFileManager defaultManager] removeItemAtPath:temporaryPath error:nil];
+	}
+	
+	NSString *downloadPath = [[[[NSBundle mainBundle] bundlePath] stringByDeletingLastPathComponent] stringByAppendingPathComponent:@"MemexTrails_1.0b1.zip"];
+	if ([[NSFileManager defaultManager] fileExistsAtPath:downloadPath]) {
+		[[NSFileManager defaultManager] removeItemAtPath:downloadPath error:nil];
+	}
+	
+	NSURL *downloadURL = [NSURL URLWithString:@"http://trails-network.net/Downloads/MemexTrails_1.0b1.zip"];
+	networkQueue = [[ASINetworkQueue alloc] init];	
+
+	ASIHTTPRequest *request = [[[ASIHTTPRequest alloc] initWithURL:downloadURL] autorelease];
+	[request setDownloadDestinationPath:downloadPath];
+	[request setTemporaryFileDownloadPath:temporaryPath];
+	[request setAllowResumeForFileDownloads:YES];
+	[networkQueue addOperation:request];
+	[networkQueue go];
+	 
+	// Let the download run for 5 seconds, which hopefully won't be enough time to grab this file. If you have a super fast connection, this test may fail, serves you right for being so smug. :)
+	NSTimer *timeoutTimer = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(stopQueue:) userInfo:nil repeats:NO];
+	
+	while (!complete) {
+		[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:1]];
+	}
+	
+	// 5 seconds is up, let's tell the queue to stop
+	[networkQueue cancelAllOperations];
+	
+	[networkQueue release];
+	networkQueue = [[ASINetworkQueue alloc] init];
+	
+	
+	unsigned long long downloadedSoFar = [[[NSFileManager defaultManager] fileAttributesAtPath:temporaryPath traverseLink:NO] fileSize];
+	BOOL success = (downloadedSoFar > 0);
+	GHAssertTrue(success,@"Failed to download part of the file, so we can't proceed with this test");
+	
+	request = [[[ASIHTTPRequest alloc] initWithURL:downloadURL] autorelease];
+	[request setDownloadDestinationPath:downloadPath];
+	[request setTemporaryFileDownloadPath:temporaryPath];
+	[request setAllowResumeForFileDownloads:YES];
+	
+	[networkQueue addOperation:request];
+	[networkQueue go];
+	
+	[networkQueue waitUntilAllOperationsAreFinished];
+	
+	unsigned long long amountDownloaded = [[[NSFileManager defaultManager] fileAttributesAtPath:downloadPath traverseLink:NO] fileSize];
+	success = (amountDownloaded == 9145357);
+	GHAssertTrue(success,@"Failed to complete the download");
+	
+	
+	[networkQueue release];
+	
+	timeoutTimer = nil;
+	
+}
+
+- (void)stopQueue:(id)sender
+{
+	complete = YES;
+}
+
 
 @end