Add ability to set custom downloader HTTP headers (fix SDWebImage#171)

Examples/SDWebImage Demo/MasterViewController.m

@@ -332,6 +332,7 @@ - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
                     @"http://static2.dmcdn.net/static/video/269/938/51839962:jpeg_preview_small.jpg?20121105214014",
                     nil];
     }
+    [SDWebImageManager.sharedManager.imageDownloader setValue:@"SDWebImage Demo" forHTTPHeaderField:@"AppName"];
     return self;
 }
 

SDWebImage/SDWebImageDownloader.h

@@ -31,6 +31,21 @@ typedef void(^SDWebImageDownloaderCompletedBlock)(UIImage *image, NSData *data,
 
 + (SDWebImageDownloader *)sharedDownloader;
 
+/**
+ * Set a value for a HTTP header to be appended to each download HTTP request.
+ *
+ * @param value The value for the header field. Use `nil` value to remove the header.
+ * @param field The name of the header field to set.
+ */
+- (void)setValue:(NSString *)value forHTTPHeaderField:(NSString *)field;
+
+/**
+ * Returns the value of the specified HTTP header field.
+ *
+ * @return The value associated with the header field field, or `nil` if there is no corresponding header field.
+ */
+- (NSString *)valueForHTTPHeaderField:(NSString *)field;
+
 /**
  * Creates a SDWebImageDownloader async downloader instance with a given URL
  *

SDWebImage/SDWebImageDownloader.m

@@ -20,6 +20,7 @@ @interface SDWebImageDownloader ()
 
 @property (strong, nonatomic) NSOperationQueue *downloadQueue;
 @property (strong, nonatomic) NSMutableDictionary *URLCallbacks;
+@property (strong, nonatomic) NSMutableDictionary *HTTPHeaders;
 // This queue is used to serialize the handling of the network responses of all the download operation in a single queue
 @property (SDDispatchQueueSetterSementics, nonatomic) dispatch_queue_t workingQueue;
 @property (SDDispatchQueueSetterSementics, nonatomic) dispatch_queue_t barrierQueue;
@@ -68,6 +69,7 @@ - (id)init
         _downloadQueue = NSOperationQueue.new;
         _downloadQueue.maxConcurrentOperationCount = 2;
         _URLCallbacks = NSMutableDictionary.new;
+        _HTTPHeaders = [NSMutableDictionary dictionaryWithObject:@"image/*" forKey:@"Accept"];
         _workingQueue = dispatch_queue_create("com.hackemist.SDWebImageDownloader", DISPATCH_QUEUE_SERIAL);
         _barrierQueue = dispatch_queue_create("com.hackemist.SDWebImageDownloaderBarrierQueue", DISPATCH_QUEUE_CONCURRENT);
     }
@@ -81,6 +83,23 @@ - (void)dealloc
     SDDispatchQueueRelease(_barrierQueue);
 }
 
+- (void)setValue:(NSString *)value forHTTPHeaderField:(NSString *)field
+{
+    if (value)
+    {
+        self.HTTPHeaders[field] = value;
+    }
+    else
+    {
+        [self.HTTPHeaders removeObjectForKey:field];
+    }
+}
+
+- (NSString *)valueForHTTPHeaderField:(NSString *)field
+{
+    return self.HTTPHeaders[field];
+}
+
 - (void)setMaxConcurrentDownloads:(NSInteger)maxConcurrentDownloads
 {
     _downloadQueue.maxConcurrentOperationCount = maxConcurrentDownloads;
@@ -102,7 +121,7 @@ - (NSInteger)maxConcurrentDownloads
         NSMutableURLRequest *request = [NSMutableURLRequest.alloc initWithURL:url cachePolicy:NSURLCacheStorageNotAllowed timeoutInterval:15];
         request.HTTPShouldHandleCookies = NO;
         request.HTTPShouldUsePipelining = YES;
-        [request addValue:@"image/*" forHTTPHeaderField:@"Accept"];
+        request.allHTTPHeaderFields = wself.HTTPHeaders;
         operation = [SDWebImageDownloaderOperation.alloc initWithRequest:request queue:wself.workingQueue options:options progress:^(NSUInteger receivedSize, long long expectedSize)
         {
             if (!wself) return;