File and site downloads are back

itch_dl/utils.py

@@ -0,0 +1,34 @@
+import re
+from typing import Optional
+
+
+class ItchDownloadError(Exception):
+    pass
+
+
+def get_int_after_marker_in_json(text: str, marker: str, key: str) -> Optional[int]:
+    """
+    Many itch.io sites use a pattern like this: Most of the HTML page
+    is prerendered, but certain interactive objects are handled with
+    JavaScript initialized with `I.WidgetHandler({"id": 123, ...})`
+    somewhere near the end of each page. Those config blocks often
+    contain metadata like game/page IDs that we want to extract.
+    """
+    marker_line: Optional[str] = None
+    for line in reversed(text.splitlines()):
+        marker_index = line.find(marker)
+        if marker_index != -1:
+            marker_line = line[marker_index:]
+            break
+
+    if marker_line is None:
+        return None
+
+    # Notice double-slashes in the f-string (not r-string)!
+    pattern = f'\\"{key}\\":\\s?(\\d+)'
+
+    found_ints = re.findall(pattern, marker_line)
+    if len(found_ints) != 1:
+        return None
+
+    return int(found_ints[0])