Added app directory

app/main.py

@@ -0,0 +1,45 @@
+#===================== Importing FastAPI necessary packages =============
+from fastapi import (
+    FastAPI,
+    HTTPException,
+    status,
+    Request,
+)
+
+from src.dependecies import authenticate_user
+from src.routers import router
+
+import base64
+import binascii
+
+
+#------------------ FastAPI variable ----------------------------------
+app = FastAPI()
+
+
+# ================ Authentication Middleware =======================
+#----------- Here authentication is based on basic scheme,
+#----------- another authentication, based on bearer scheme, is used throughout
+#---------- the application (as decribed in FastAPI oficial documentation)
+@app.middleware("http")
+async def authenticate(request: Request, call_next):
+
+#-------------------- Authentication basic scheme -----------------------------
+    if "Authorization" in request.headers:
+        auth = request.headers["Authorization"]
+        try:
+            scheme, credentials = auth.split()
+            if scheme.lower() == 'basic':
+                decoded = base64.b64decode(credentials).decode("ascii")
+                username, _, password = decoded.partition(":")
+                request.state.user = await authenticate_user(username, password)
+        except (ValueError, UnicodeDecodeError, binascii.Error):
+            raise HTTPException(
+                status_code=status.HTTP_401_UNAUTHORIZED,
+                detail="Invalid basic auth credentials"
+            )
+
+    response = await call_next(request)
+    return response
+
+app.include_router(router)