Fix WhatsAppChatLoader : Enable parsing additional formats (#6663)

- Description: Updated regex to support a new format that was observed
when whatsapp chat was exported.
  - Issue: #6654
  - Dependencies: No new dependencies
  - Tag maintainer: @rlancemartin, @eyurtsev

langchain/document_loaders/whatsapp_chat.py

@@ -40,7 +40,7 @@ class WhatsAppChatLoader(BaseLoader):
                 (?:
                     :\d{2}
                 )?
-                (?:[ _](?:AM|PM))?
+                (?:[\s_](?:AM|PM))?
             )
             \]?
             [\s-]*
@@ -50,7 +50,9 @@ class WhatsAppChatLoader(BaseLoader):
             (.+)
         """
         for line in lines:
-            result = re.match(message_line_regex, line.strip(), flags=re.VERBOSE)
+            result = re.match(
+                message_line_regex, line.strip(), flags=re.VERBOSE | re.IGNORECASE
+            )
             if result:
                 date, sender, text = result.groups()
                 text_content += concatenate_rows(date, sender, text)

tests/integration_tests/document_loaders/test_whatsapp_chat.py

@@ -18,4 +18,6 @@ def test_whatsapp_chat_loader() -> None:
         "User 1 on 1/23/23, 3:22_AM: And let me know if anything changes\n\n"
         "~ User name 2 on 1/24/21, 12:41:03 PM: Of course!\n\n"
         "~ User 2 on 2023/5/4, 16:13:23: See you!\n\n"
+        "User 1 on 7/19/22, 11:32 PM: Hello\n\n"
+        "User 2 on 7/20/22, 11:32 am: Goodbye\n\n"
     )

tests/integration_tests/examples/whatsapp_chat.txt

@@ -3,4 +3,6 @@
 1/23/23, 3:19 AM - User 2: Bye!
 1/23/23, 3:22_AM - User 1: And let me know if anything changes
 [1/24/21, 12:41:03 PM] ~ User name 2: Of course!
-[2023/5/4, 16:13:23] ~ User 2: See you!
+[2023/5/4, 16:13:23] ~ User 2: See you!
+7/19/22, 11:32 PM - User 1: Hello
+7/20/22, 11:32 am - User 2: Goodbye