Add FastAPI + SQLAlchemy 2.x example (#49)

Author: solfrii

.gitignore

@@ -134,3 +134,4 @@ dmypy.json
 .pyre/
 
 *.code-workspace
+.idea/

examples/fastapi_sqlalchemy/Makefile

@@ -0,0 +1,9 @@
+all: install run
+
+.PHONY: fastapi
+run:
+	poetry run fastapi dev --reload --port=8090 example.py
+
+.PHONY: install
+install:
+	poetry install

examples/fastapi_sqlalchemy/README.md

@@ -0,0 +1,12 @@
+## FastAPI + SQLAlchemy 2.x Example
+
+- Uses in-memory SQLite 3 instance
+- Creates User mode
+- Creates "admin/admin" superuser
+
+```bash
+make install  # Creates virtualenv with Poetry
+make run      # Runs fastapi dev
+```
+
+So open `http://127.0.0.1:8090/admin/` and have a fun!

examples/fastapi_sqlalchemy/example.py

@@ -0,0 +1,80 @@
+from fastapi import FastAPI
+from sqlalchemy import Boolean, Integer, String, select
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+from fastadmin import SqlAlchemyModelAdmin, register, fastapi_app as admin_app
+
+
+sqlalchemy_engine = create_async_engine("sqlite+aiosqlite:///:memory:", echo=True)
+sqlalchemy_sessionmaker = async_sessionmaker(sqlalchemy_engine, expire_on_commit=False)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+class User(Base):
+    __tablename__ = "user"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, nullable=False)
+    username: Mapped[str] = mapped_column(String(length=255), nullable=False)
+    password: Mapped[str] = mapped_column(String(length=255), nullable=False)
+    is_superuser: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+    is_active: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+
+    def __str__(self):
+        return self.username
+
+
+async def init_db():
+    async with sqlalchemy_engine.begin() as c:
+        await c.run_sync(Base.metadata.drop_all)
+        await c.run_sync(Base.metadata.create_all)
+
+
+async def create_superuser():
+    async with sqlalchemy_sessionmaker() as s:
+        user = User(
+            username="admin",
+            password="admin",
+            is_superuser=True,
+            is_active=True,
+        )
+        s.add(user)
+        await s.commit()
+
+
+@register(User, sqlalchemy_sessionmaker=sqlalchemy_sessionmaker)
+class UserAdmin(SqlAlchemyModelAdmin):
+    exclude = ("hash_password",)
+    list_display = ("id", "username", "is_superuser", "is_active")
+    list_display_links = ("id", "username")
+    list_filter = ("id", "username", "is_superuser", "is_active")
+    search_fields = ("username",)
+
+    async def authenticate(self, username, password):
+        sessionmaker = self.get_sessionmaker()
+        async with sessionmaker() as session:
+            query = select(User).filter_by(
+                username=username, password=password, is_superuser=True
+            )
+            result = await session.scalars(query)
+            user = result.first()
+            if not user:
+                return None
+            if password != user.password:
+                return None
+            return user.id
+
+
+app = FastAPI()
+
+
+@app.on_event("startup")
+async def startup():
+    await init_db()
+    await create_superuser()
+
+
+app.mount("/admin", admin_app)