saved_snippets: Add backend for saved snippets.

Part of #31227.

zerver/views/saved_snippets.py

@@ -0,0 +1,55 @@
+from typing import Annotated
+
+from django.conf import settings
+from django.http import HttpRequest, HttpResponse
+from pydantic import StringConstraints
+
+from zerver.actions.saved_snippets import (
+    do_create_saved_snippet,
+    do_delete_saved_snippet,
+    do_get_saved_snippets,
+)
+from zerver.lib.response import json_success
+from zerver.lib.typed_endpoint import typed_endpoint
+from zerver.models import SavedSnippet, UserProfile
+
+
+def get_saved_snippets(
+    request: HttpRequest,
+    user_profile: UserProfile,
+) -> HttpResponse:
+    return json_success(request, data={"saved_snippets": do_get_saved_snippets(user_profile)})
+
+
+@typed_endpoint
+def create_saved_snippet(
+    request: HttpRequest,
+    user_profile: UserProfile,
+    *,
+    title: Annotated[
+        str,
+        StringConstraints(
+            min_length=1, max_length=SavedSnippet.MAX_TITLE_LENGTH, strip_whitespace=True
+        ),
+    ],
+    content: Annotated[
+        str,
+        StringConstraints(
+            min_length=1, max_length=settings.MAX_MESSAGE_LENGTH, strip_whitespace=True
+        ),
+    ],
+) -> HttpResponse:
+    title = title.strip()
+    content = content.strip()
+    saved_snippet = do_create_saved_snippet(title, content, user_profile)
+    return json_success(request, data={"saved_snippet_id": saved_snippet.id})
+
+
+def delete_saved_snippet(
+    request: HttpRequest,
+    user_profile: UserProfile,
+    *,
+    saved_snippet_id: int,
+) -> HttpResponse:
+    do_delete_saved_snippet(saved_snippet_id, user_profile)
+    return json_success(request)