snapshot of https://github.com/zulip/zulip.git @ 48c69911c7dd4e03b20552eb3bd77ad8151c1357 (2026-09-15)

zerver/lib/utils.py

@@ -0,0 +1,77 @@
+import hashlib
+import logging
+import re
+import secrets
+from collections.abc import Callable
+from typing import TypeVar
+
+from django.db import models
+
+T = TypeVar("T")
+
+
+def generate_api_key() -> str:
+    api_key = ""
+    while len(api_key) < 32:
+        # One iteration suffices 99.4992% of the time.
+        api_key += secrets.token_urlsafe(3 * 9).replace("_", "").replace("-", "")
+    return api_key[:32]
+
+
+def has_api_key_format(key: str) -> bool:
+    return bool(re.fullmatch(r"([A-Za-z0-9]){32}", key))
+
+
+def assert_is_not_none(value: T | None) -> T:
+    assert value is not None
+    return value
+
+
+def process_list_in_batches(
+    lst: list[T], chunk_size: int, process_batch: Callable[[list[T]], None]
+) -> None:
+    offset = 0
+    total_message_length = len(lst)
+    while True:
+        items = lst[offset : offset + chunk_size]
+        if not items:
+            break
+        process_batch(items)
+        offset = min(offset + chunk_size, total_message_length)
+        logging.info("Processed messages up to %s / %s", offset, total_message_length)
+
+
+def optional_bytes_to_mib(value: int | None) -> int | None:
+    if value is None:
+        return None
+    else:
+        return value >> 20
+
+
+def get_fk_field_name(model: type[models.Model], related_model: type[models.Model]) -> str | None:
+    """
+    Get the name of the foreign key field in model, pointing the related_model table.
+    Returns None if there is no such field.
+
+    Example usage:
+
+    get_fk_field_name(UserProfile, Realm) returns "realm"
+    """
+
+    fields = model._meta.get_fields()
+    foreign_key_fields_to_related_model = [
+        field
+        for field in fields
+        if hasattr(field, "related_model") and field.related_model == related_model
+    ]
+
+    if len(foreign_key_fields_to_related_model) == 0:
+        return None
+
+    assert len(foreign_key_fields_to_related_model) == 1
+
+    return foreign_key_fields_to_related_model[0].name
+
+
+def sha256_hash(text: str) -> str:
+    return hashlib.sha256(text.encode()).hexdigest()