1 files changed, 54 insertions, 0 deletions
diff --git a/gallery_dl/extractor/message.py b/gallery_dl/extractor/message.py
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+++ b/gallery_dl/extractor/message.py
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+# -*- coding: utf-8 -*-
+
+# Copyright 2015-2018 Mike Fährmann
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+
+
+class Message():
+    """Enum for message identifiers
+
+    Extractors yield their results as message-tuples, where the first element
+    is one of the following identifiers. This message-identifier determines
+    the type and meaning of the other elements in such a tuple.
+
+    - Message.Version:
+      - Message protocol version (currently always '1')
+      - 2nd element specifies the version of all following messages as integer
+
+    - Message.Directory:
+      - Sets the target directory for all following images
+      - 2nd element is a dictionary containing general metadata
+
+    - Message.Url:
+      - Image URL and its metadata
+      - 2nd element is the URL as a string
+      - 3rd element is a dictionary with image-specific metadata
+
+    - Message.Headers:  # obsolete
+      - HTTP headers to use while downloading
+      - 2nd element is a dictionary with header-name and -value pairs
+
+    - Message.Cookies:  # obsolete
+      - Cookies to use while downloading
+      - 2nd element is a dictionary with cookie-name and -value pairs
+
+    - Message.Queue:
+      - (External) URL that should be handled by another extractor
+      - 2nd element is the (external) URL as a string
+      - 3rd element is a dictionary containing URL-specific metadata
+
+    - Message.Urllist:
+      - Same as Message.Url, but its 2nd element is a list of multiple URLs
+      - The additional URLs serve as a fallback if the primary one fails
+    """
+
+    Version = 1
+    Directory = 2
+    Url = 3
+    #  Headers = 4
+    #  Cookies = 5
+    Queue = 6
+    Urllist = 7