From e9fce441956642bef3548e3181d72a88317efa65 Mon Sep 17 00:00:00 2001
From: Simon Willison <simonw@eventbrite.com>
Date: Fri, 10 Nov 2017 12:26:37 -0800
Subject: [PATCH] Don't serve cache headers in debug or refresh modes

---
 datasette/app.py | 11 +++++++----
 datasette/cli.py |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/datasette/app.py b/datasette/app.py
index 7e11f3c1..690d7d5a 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -78,6 +78,7 @@ class BaseView(HTTPMethodView):
         self.files = datasette.files
         self.jinja = datasette.jinja
         self.executor = datasette.executor
+        self.cache_headers = datasette.cache_headers
 
     def redirect(self, request, path):
         if request.query_string:
@@ -183,9 +184,10 @@ class BaseView(HTTPMethodView):
                 **context,
             )
         # Set far-future cache expiry
-        r.headers['Cache-Control'] = 'max-age={}'.format(
-            365 * 24 * 60 * 60
-        )
+        if self.cache_headers:
+            r.headers['Cache-Control'] = 'max-age={}'.format(
+                365 * 24 * 60 * 60
+            )
         return r
 
 
@@ -379,12 +381,13 @@ def resolve_db_name(files, db_name, **kwargs):
 
 
 class Datasette:
-    def __init__(self, files, num_threads=3):
+    def __init__(self, files, num_threads=3, cache_headers=True):
         self.files = files
         self.num_threads = num_threads
         self.executor = futures.ThreadPoolExecutor(
             max_workers=num_threads
         )
+        self.cache_headers = cache_headers
 
     def app(self):
         app = Sanic(__name__)
diff --git a/datasette/cli.py b/datasette/cli.py
index 9284e867..23b4601d 100644
--- a/datasette/cli.py
+++ b/datasette/cli.py
@@ -29,5 +29,5 @@ def serve(files, host, port, debug, reload):
         hupper.start_reloader('datasette.cli.serve')
 
     click.echo('Serve! files={} on port {}'.format(files, port))
-    app = Datasette(files).app()
+    app = Datasette(files, cache_headers=not debug and not reload).app()
     app.run(host=host, port=port, debug=debug)