Import //fetch from Web Platform Tests.

third_party/WebKit/LayoutTests/external/wpt/fetch/api/request/resources/cache.py

+def main(request, response):
+    token = request.GET.first("token", None)
+    if "querystate" in request.GET:
+        from json import JSONEncoder
+        response.headers.set("Content-Type", "text/plain")
+        return JSONEncoder().encode(request.server.stash.take(token))
+    content = request.GET.first("content", None)
+    tag = request.GET.first("tag", None)
+    date = request.GET.first("date", None)
+    expires = request.GET.first("expires", None)
+    vary = request.GET.first("vary", None)
+    cc = request.GET.first("cache_control", None)
+    redirect = request.GET.first("redirect", None)
+    inm = request.headers.get("If-None-Match", None)
+    ims = request.headers.get("If-Modified-Since", None)
+    pragma = request.headers.get("Pragma", None)
+    cache_control = request.headers.get("Cache-Control", None)
+    ignore = "ignore" in request.GET
+
+    if tag:
+        tag = '"%s"' % tag
+
+    server_state = request.server.stash.take(token)
+    if not server_state:
+        server_state = []
+    state = dict()
+    if not ignore:
+        if inm:
+            state["If-None-Match"] = inm
+        if ims:
+            state["If-Modified-Since"] = ims
+        if pragma:
+            state["Pragma"] = pragma
+        if cache_control:
+            state["Cache-Control"] = cache_control
+    server_state.append(state)
+    request.server.stash.put(token, server_state)
+
+    if tag:
+        response.headers.set("ETag", '%s' % tag)
+    elif date:
+        response.headers.set("Last-Modified", date)
+    if expires:
+        response.headers.set("Expires", expires)
+    if vary:
+        response.headers.set("Vary", vary)
+    if cc:
+        response.headers.set("Cache-Control", cc)
+
+    # The only-if-cached redirect tests wants CORS to be okay, the other tests
+    # are all same-origin anyways and don't care.
+    response.headers.set("Access-Control-Allow-Origin", "*");
+
+    if redirect:
+        response.headers.set("Location", redirect);
+        response.status = (302, "Redirect")
+        return ""
+    elif ((inm is not None and inm == tag) or
+          (ims is not None and ims == date)):
+        response.status = (304, "Not Modified")
+        return ""
+    else:
+        response.status = (200, "OK")
+        response.headers.set("Content-Type", "text/plain")
+        return content