[zerochan] normalize "No results" output message (#8313)

catch and handle '404 Not Found' responses

gallery_dl/extractor/zerochan.py

@@ -193,7 +193,13 @@ class ZerochanTagExtractor(ZerochanExtractor):
         metadata = self.config("metadata")
 
         while True:
-            page = self.request(url, params=params, expected=(500,)).text
+            try:
+                page = self.request(
+                    url, params=params, expected=(500,)).text
+            except exception.HttpError as exc:
+                if exc.status == 404:
+                    return
+                raise
             thumbs = text.extr(page, '<ul id="thumbs', '</ul>')
             extr = text.extract_from(thumbs)
 
@@ -232,7 +238,13 @@ class ZerochanTagExtractor(ZerochanExtractor):
         }
 
         while True:
-            response = self.request(url, params=params, allow_redirects=False)
+            try:
+                response = self.request(
+                    url, params=params, allow_redirects=False)
+            except exception.HttpError as exc:
+                if exc.status == 404:
+                    return
+                raise
 
             if response.status_code >= 300:
                 url = text.urljoin(self.root, response.headers["location"])
@@ -276,12 +288,18 @@ class ZerochanImageExtractor(ZerochanExtractor):
     pattern = BASE_PATTERN + r"/(\d+)"
     example = "https://www.zerochan.net/12345"
 
-    def __init__(self, match):
-        ZerochanExtractor.__init__(self, match)
-        self.image_id = match[1]
-
     def posts(self):
-        post = self._parse_entry_html(self.image_id)
+        image_id = self.groups[0]
+
+        try:
+            post = self._parse_entry_html(image_id)
+        except exception.HttpError as exc:
+            if exc.status in (404, 410):
+                if msg := text.extr(exc.response.text, "<h2>", "<"):
+                    self.log.warning(f"'{msg}'")
+                return ()
+            raise
+
         if self.config("metadata"):
-            post.update(self._parse_entry_api(self.image_id))
+            post.update(self._parse_entry_api(image_id))
         return (post,)

test/results/zerochan.py

@@ -45,6 +45,13 @@ __tests__ = (
     "width"      : r"re:^\d+$",
 },
 
+{
+    "#url"     : "https://www.zerochan.net/non_existant_tag",
+    "#comment" : "handle HttpError exception (#8313)",
+    "#class"   : zerochan.ZerochanTagExtractor,
+    "#count"   : 0,
+},
+
 {
     "#url"     : "https://www.zerochan.net/2920445",
     "#category": ("booru", "zerochan", "image"),
@@ -341,4 +348,20 @@ __tests__ = (
     ],
 },
 
+{
+    "#url"     : "https://www.zerochan.net/1",
+    "#category": ("booru", "zerochan", "image"),
+    "#class"   : zerochan.ZerochanImageExtractor,
+    "#count"   : 0,
+    "#log"     : "'deleted'",
+},
+
+{
+    "#url"     : "https://www.zerochan.net/9876540",
+    "#category": ("booru", "zerochan", "image"),
+    "#class"   : zerochan.ZerochanImageExtractor,
+    "#count"   : 0,
+    "#log"     : "'Not found'",
+},
+
 )