Make http error cache control behavior configurable. (#444)

* Make http error cache control behavior configurable.

* Update parameter naming as requested by @vincentsarago.

src/titiler/core/tests/test_cache_middleware.py

@@ -5,6 +5,7 @@
 
 from fastapi import FastAPI, Path
 
+from starlette.responses import Response
 from starlette.testclient import TestClient
 
 
@@ -36,9 +37,19 @@ async def tiles(
         """tiles."""
         return "yeah"
 
+    @app.get("/emptytiles/{z}/{x}/{y}")
+    async def emptytiles(
+        z: int = Path(..., ge=0, le=30, description="Mercator tiles's zoom level"),
+        x: int = Path(..., description="Mercator tiles's column"),
+        y: int = Path(..., description="Mercator tiles's row"),
+    ):
+        """tiles."""
+        return Response(status_code=404)
+
     app.add_middleware(
         CacheControlMiddleware,
         cachecontrol="public",
+        cachecontrol_max_http_code=400,
         exclude_path={r"/route1", r"/route2", r"/tiles/[0-1]/.+"},
     )
 
@@ -58,3 +69,6 @@ async def tiles(
 
     response = client.get("/tiles/3/1/1")
     assert response.headers["Cache-Control"] == "public"
+
+    response = client.get("/emptytiles/3/1/1")
+    assert not response.headers.get("Cache-Control")

src/titiler/core/titiler/core/middleware.py

@@ -19,6 +19,7 @@ def __init__(
         self,
         app: ASGIApp,
         cachecontrol: Optional[str] = None,
+        cachecontrol_max_http_code: Optional[int] = 500,
         exclude_path: Optional[Set[str]] = None,
     ) -> None:
         """Init Middleware.
@@ -31,6 +32,7 @@ def __init__(
         """
         super().__init__(app)
         self.cachecontrol = cachecontrol
+        self.cachecontrol_max_http_code = cachecontrol_max_http_code
         self.exclude_path = exclude_path or set()
 
     async def dispatch(self, request: Request, call_next):
@@ -41,7 +43,10 @@ async def dispatch(self, request: Request, call_next):
                 if re.match(path, request.url.path):
                     return response
 
-            if request.method in ["HEAD", "GET"] and response.status_code < 500:
+            if (
+                request.method in ["HEAD", "GET"]
+                and response.status_code < self.cachecontrol_max_http_code
+            ):
                 response.headers["Cache-Control"] = self.cachecontrol
 
         return response