Added support for sending headers when using download_file.

Allows HTTP conditional GET for servers which support it.

deluge/httpdownloader.py

@@ -41,16 +41,17 @@ class HTTPDownloader(client.HTTPDownloader):
     """
     Factory class for downloading files and keeping track of progress.
     """
-    def __init__(self, url, filename, part_callback=None):
+    def __init__(self, url, filename, part_callback=None, headers=None):
         """
         :param url: str, the url to download from
         :param filename: str, the filename to save the file as
         :param part_callback: func, a function to be called when a part of data
             is received, it's signature should be: func(data, current_length, total_length)
+        :param headers: dict, any optional headers to send
         """
         self.__part_callback = part_callback
         self.current_length = 0
-        client.HTTPDownloader.__init__(self, url, filename)
+        client.HTTPDownloader.__init__(self, url, filename, headers=headers)
 
     def gotStatus(self, version, status, message):
         self.code = int(status)
@@ -77,7 +78,7 @@ class HTTPDownloader(client.HTTPDownloader):
 
         return client.HTTPDownloader.pagePart(self, data)
 
-def download_file(url, filename, callback=None):
+def download_file(url, filename, callback=None, headers=None):
     """
     Downloads a file from a specific URL and returns a Deferred.  You can also
     specify a callback function to be called as parts are received.
@@ -86,10 +87,14 @@ def download_file(url, filename, callback=None):
     :param filename: str, the filename to save the file as
     :param callback: func, a function to be called when a part of data is received,
          it's signature should be: func(data, current_length, total_length)
+    :param headers: dict, any optional headers to send
+    :raises t.w.e.PageRedirect: when server responds with a temporary redirect
+         or permanently moved.
+    :raises t.w.e.Error: for all other HTTP response errors (besides OK)
     """
     url = str(url)
     scheme, host, port, path = client._parse(url)
-    factory = HTTPDownloader(url, filename, callback)
+    factory = HTTPDownloader(url, filename, callback, headers)
     if scheme == "https":
         from twisted.internet import ssl
         reactor.connectSSL(host, port, factory, ssl.ClientContextFactory())