[kemonoparty] add 'revision_hash' metadata (#4706, #4727, #5013)

A SHA1 hexdigest of other relevant metadata fields like
title, content, file and attachment URLs.

This value does NOT reflect which revisions are listed on the website.
Neither does 'edited' or any other metadata field (combinations).

gallery_dl/extractor/kemonoparty.py

@@ -9,9 +9,10 @@
 """Extractors for https://kemono.party/"""
 
 from .common import Extractor, Message
-from .. import text, exception
+from .. import text, util, exception
 from ..cache import cache, memcache
 import itertools
+import json
 import re
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.|beta\.)?(kemono|coomer)\.(party|su)"
@@ -37,10 +38,14 @@ def __init__(self, match):
         Extractor.__init__(self, match)
 
     def _init(self):
+        self.revisions = self.config("revisions")
         self._prepare_ddosguard_cookies()
         self._find_inline = re.compile(
             r'src="(?:https?://(?:kemono|coomer)\.(?:party|su))?(/inline/[^"]+'
             r'|/[0-9a-f]{2}/[0-9a-f]{2}/[0-9a-f]{64}\.[^"]+)').findall
+        self._json_dumps = json.JSONEncoder(
+            ensure_ascii=False, check_circular=False,
+            sort_keys=True, separators=(",", ":")).encode
 
     def items(self):
         find_hash = re.compile(HASH_PATTERN).match
@@ -223,11 +228,23 @@ def _post_revisions(self, url):
 
         idx = len(revs)
         for rev in revs:
+            rev["revision_hash"] = self._revision_hash(rev)
             rev["revision_index"] = idx
             idx -= 1
 
         return revs
 
+    def _revision_hash(self, revision):
+        rev = revision.copy()
+        rev.pop("revision_id", None)
+        rev.pop("added", None)
+        rev.pop("next", None)
+        rev.pop("prev", None)
+        rev["file"].pop("name", None)
+        for a in rev["attachments"]:
+            a.pop("name", None)
+        return util.sha1(self._json_dumps(rev))
+
 
 def _validate(response):
     return (response.headers["content-length"] != "9" or
@@ -252,13 +269,13 @@ def posts(self):
         url = self.api_url
         params = text.parse_query(self.query)
         params["o"] = text.parse_int(params.get("o"))
-        revisions = self.config("revisions")
 
         while True:
             posts = self.request(url, params=params).json()
 
-            if revisions:
+            if self.revisions:
                 for post in posts:
+                    post["revision_hash"] = self._revision_hash(post)
                     post["revision_id"] = 0
                     post_url = "{}/post/{}".format(self.api_url, post["id"])
                     try:
@@ -296,7 +313,8 @@ def __init__(self, match):
     def posts(self):
         if not self.revision:
             post = self.request(self.api_url).json()
-            if self.config("revisions"):
+            if self.revisions:
+                post["revision_hash"] = self._revision_hash(post)
                 post["revision_id"] = 0
                 try:
                     revs = self._post_revisions(self.api_url)

test/results/kemonoparty.py

@@ -177,6 +177,7 @@
 
     "revision_id": 142470,
     "revision_index": 2,
+    "revision_hash": "e0e93281495e151b11636c156e52bfe9234c2a40",
 },
 
 {
@@ -190,6 +191,7 @@
 
     "revision_id": range(134996, 3052965),
     "revision_index": range(1, 9),
+    "revision_hash": r"re:^[0-9a-f]{40}$",
 },