adds function to responseFilePath (streaming into a file, if set)

adds total/offsetContentLength. We really need those in case we pause/resume.

AFNetworking/AFHTTPRequestOperation.h

@@ -50,9 +50,28 @@ extern NSString * AFCreateIncompleteDownloadDirectoryPath(void);
 @property (readonly, nonatomic, retain) NSHTTPURLResponse *response;
 
 /**
- 
+ Set a target file for the response, will stream directly into this destination.
+ Defaults to nil, which will use a memory stream. Will create a new outputStream on change.
+
+ Note: Changing this while the request is not in ready state will be ignored.
  */
-@property (readonly, nonatomic, copy) NSString *responseFilePath;
+@property (nonatomic, copy) NSString *responseFilePath;
+
+
+/** 
+ Expected total length. This is different than expectedContentLength if the file is resumed.
+ On regular requests, this is equal to self.response.expectedContentLength unless we resume a request.
+ 
+ Note: this can also be -1 if the file size is not sent (*)
+ */
+@property (assign, readonly) long long totalContentLength;
+
+/** 
+ Indicator for the file offset on partial/resumed downloads.
+ This is greater than zero if the file download is resumed.
+ */
+@property (assign, readonly) long long offsetContentLength;
+
 
 ///----------------------------------------------------------
 /// @name Managing And Checking For Acceptable HTTP Responses

AFNetworking/AFHTTPRequestOperation.m

@@ -114,7 +114,8 @@ NSString * AFCreateIncompleteDownloadDirectoryPath(void) {
 @property (readwrite, nonatomic, retain) NSURLRequest *request;
 @property (readwrite, nonatomic, retain) NSHTTPURLResponse *response;
 @property (readwrite, nonatomic, retain) NSError *HTTPError;
-@property (readwrite, nonatomic, copy) NSString *responseFilePath;
+@property (assign) long long totalContentLength;
+@property (assign) long long offsetContentLength;
 @end
 
 @implementation AFHTTPRequestOperation
@@ -122,6 +123,8 @@ NSString * AFCreateIncompleteDownloadDirectoryPath(void) {
 @synthesize responseFilePath = _responseFilePath;
 @synthesize successCallbackQueue = _successCallbackQueue;
 @synthesize failureCallbackQueue = _failureCallbackQueue;
+@synthesize totalContentLength = _totalContentLength;
+@synthesize offsetContentLength = _offsetContentLength;
 @dynamic request;
 @dynamic response;
 
@@ -241,6 +244,19 @@ NSString * AFCreateIncompleteDownloadDirectoryPath(void) {
     };
 }
 
+- (void)setResponseFilePath:(NSString *)responseFilePath {
+    if ([self isReady] && responseFilePath != _responseFilePath) {
+        [_responseFilePath release];
+        _responseFilePath = [responseFilePath retain];
+        
+        if (responseFilePath) {
+            self.outputStream = [NSOutputStream outputStreamToFileAtPath:responseFilePath append:NO];
+        }else {
+            self.outputStream = [NSOutputStream outputStreamToMemory];
+        }
+    }
+}
+
 #pragma mark - AFHTTPClientOperation
 
 + (NSIndexSet *)acceptableStatusCodes {
@@ -283,6 +299,8 @@ didReceiveResponse:(NSURLResponse *)response
     self.response = (NSHTTPURLResponse *)response;
     
     // 206 = Partial Content.
+    long long totalContentLength = self.response.expectedContentLength;
+    long long fileOffset = 0;
     if ([self.response statusCode] != 206) {
         if ([self.outputStream propertyForKey:NSStreamFileCurrentOffsetKey]) {
             [self.outputStream setProperty:[NSNumber numberWithInteger:0] forKey:NSStreamFileCurrentOffsetKey];
@@ -291,8 +309,19 @@ didReceiveResponse:(NSURLResponse *)response
                 self.outputStream = [NSOutputStream outputStreamToMemory];
             }
         }
+    }else {
+        NSString *contentRange = [self.response.allHeaderFields valueForKey:@"Content-Range"];
+        if ([contentRange hasPrefix:@"bytes"]) {
+            NSArray *bytes = [contentRange componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@" -/"]];
+            if ([bytes count] == 4) {
+                fileOffset = [[bytes objectAtIndex:1] longLongValue];
+                totalContentLength = [[bytes objectAtIndex:2] longLongValue] ?: -1; // if this is *, it's converted to 0, but -1 is default.
+            }
+        }
+
     }
-    
+    self.offsetContentLength = MAX(fileOffset, 0);
+    self.totalContentLength = totalContentLength;
     [self.outputStream open];
 }