push: Implement HTTP/2 server push (#3573)

* push: Implement HTTP/2 server push (close #3551)

* push: Abstract header ops by embedding into new struct type

This will allow us to add more fields to customize headers in
push-specific ways in the future.

* push: Ensure Link resources are pushed before response is written

* Change header name from X-Caddy-Push to Caddy-Push

1 files changed, 85 insertions, 0 deletions

diff --git a/modules/caddyhttp/push/link_test.go b/modules/caddyhttp/push/link_test.go
new file mode 100644
index 0000000..238e284
--- /dev/null
+++ b/modules/caddyhttp/push/link_test.go
@@ -0,0 +1,85 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package push
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseLinkHeader(t *testing.T) {
+	testCases := []struct {
+		header            string
+		expectedResources []linkResource
+	}{
+		{
+			header:            "</resource>; as=script",
+			expectedResources: []linkResource{{uri: "/resource", params: map[string]string{"as": "script"}}},
+		},
+		{
+			header:            "</resource>",
+			expectedResources: []linkResource{{uri: "/resource", params: map[string]string{}}},
+		},
+		{
+			header:            "</resource>; nopush",
+			expectedResources: []linkResource{{uri: "/resource", params: map[string]string{"nopush": "nopush"}}},
+		},
+		{
+			header:            "</resource>;nopush;rel=next",
+			expectedResources: []linkResource{{uri: "/resource", params: map[string]string{"nopush": "nopush", "rel": "next"}}},
+		},
+		{
+			header: "</resource>;nopush;rel=next,</resource2>;nopush",
+			expectedResources: []linkResource{
+				{uri: "/resource", params: map[string]string{"nopush": "nopush", "rel": "next"}},
+				{uri: "/resource2", params: map[string]string{"nopush": "nopush"}},
+			},
+		},
+		{
+			header: "</resource>,</resource2>",
+			expectedResources: []linkResource{
+				{uri: "/resource", params: map[string]string{}},
+				{uri: "/resource2", params: map[string]string{}},
+			},
+		},
+		{
+			header:            "malformed",
+			expectedResources: []linkResource{},
+		},
+		{
+			header:            "<malformed",
+			expectedResources: []linkResource{},
+		},
+		{
+			header:            ",",
+			expectedResources: []linkResource{},
+		},
+		{
+			header:            ";",
+			expectedResources: []linkResource{},
+		},
+		{
+			header:            "</resource> ; ",
+			expectedResources: []linkResource{{uri: "/resource", params: map[string]string{}}},
+		},
+	}
+
+	for i, test := range testCases {
+		actualResources := parseLinkHeader(test.header)
+		if !reflect.DeepEqual(actualResources, test.expectedResources) {
+			t.Errorf("Test %d (header: %s) - expected resources %v, got %v",
+				i, test.header, test.expectedResources, actualResources)
+		}
+	}
+}