[downloader.http] implement file-specific HTTP headers

gallery_dl/downloader/http.py

@@ -77,12 +77,15 @@ class HttpDownloader(DownloaderBase):
                 time.sleep(min(2 ** (tries-1), 1800))
             tries += 1
 
+            headers = {}
             # check for .part file
             filesize = pathfmt.part_size()
             if filesize:
-                headers = {"Range": "bytes={}-".format(filesize)}
-            else:
-                headers = None
+                headers["Range"] = "bytes={}-".format(filesize)
+            # file-specific headers
+            extra = pathfmt.kwdict.get("_http_headers")
+            if extra:
+                headers.update(extra)
 
             # connect to (remote) source
             try:

test/test_results.py

@@ -189,7 +189,7 @@ class ResultJob(job.DownloadJob):
         self._update_url(url)
         self._update_kwdict(kwdict)
         self._update_archive(kwdict)
-        self._update_content(url)
+        self._update_content(url, kwdict)
         self.format_filename(kwdict)
 
     def handle_directory(self, kwdict):
@@ -217,9 +217,10 @@ class ResultJob(job.DownloadJob):
         self.archive_list.append(archive_id)
         self.archive_hash.update(archive_id.encode())
 
-    def _update_content(self, url):
+    def _update_content(self, url, kwdict):
         if self.content:
             scheme = url.partition(":")[0]
+            self.fileobj.kwdict = kwdict
             self.get_downloader(scheme).download(url, self.fileobj)