use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/mholt/caddy/caddyhttp/push/handler.go

@@ -0,0 +1,144 @@
+// Copyright 2015 Light Code Labs, LLC
+//
+// 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 (
+	"net/http"
+	"strings"
+
+	"github.com/mholt/caddy/caddyhttp/httpserver"
+)
+
+func (h Middleware) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
+	pusher, hasPusher := w.(http.Pusher)
+
+	// no push possible, carry on
+	if !hasPusher {
+		return h.Next.ServeHTTP(w, r)
+	}
+
+	// check if this is a request for the pushed resource (avoid recursion)
+	if _, exists := r.Header[pushHeader]; exists {
+		return h.Next.ServeHTTP(w, r)
+	}
+
+	headers := h.filterProxiedHeaders(r.Header)
+
+	// push first
+outer:
+	for _, rule := range h.Rules {
+		urlPath := r.URL.Path
+		matches := httpserver.Path(urlPath).Matches(rule.Path)
+		// Also check IndexPages when requesting a directory
+		if !matches {
+			indexFile, isIndexFile := httpserver.IndexFile(h.Root, urlPath, h.indexPages)
+			if isIndexFile {
+				matches = httpserver.Path(indexFile).Matches(rule.Path)
+			}
+		}
+		if matches {
+			for _, resource := range rule.Resources {
+				pushErr := pusher.Push(resource.Path, &http.PushOptions{
+					Method: resource.Method,
+					Header: h.mergeHeaders(headers, resource.Header),
+				})
+				if pushErr != nil {
+					// if we cannot push (either not supported or concurrent streams are full - break)
+					break outer
+				}
+			}
+		}
+	}
+
+	// serve later
+	code, err := h.Next.ServeHTTP(w, r)
+
+	// push resources returned in Link headers from upstream middlewares or proxied apps
+	if links, exists := w.Header()["Link"]; exists {
+		h.servePreloadLinks(pusher, headers, links)
+	}
+
+	return code, err
+}
+
+// servePreloadLinks parses Link headers from backend and pushes resources found in them.
+// For accepted header formats check parseLinkHeader function.
+//
+// If resource has 'nopush' attribute then it will be omitted.
+func (h Middleware) servePreloadLinks(pusher http.Pusher, headers http.Header, resources []string) {
+outer:
+	for _, resource := range resources {
+		for _, resource := range parseLinkHeader(resource) {
+			if _, exists := resource.params["nopush"]; exists {
+				continue
+			}
+
+			if h.isRemoteResource(resource.uri) {
+				continue
+			}
+
+			err := pusher.Push(resource.uri, &http.PushOptions{
+				Method: http.MethodGet,
+				Header: headers,
+			})
+
+			if err != nil {
+				break outer
+			}
+		}
+	}
+}
+
+func (h Middleware) isRemoteResource(resource string) bool {
+	return strings.HasPrefix(resource, "//") ||
+		strings.HasPrefix(resource, "http://") ||
+		strings.HasPrefix(resource, "https://")
+}
+
+func (h Middleware) mergeHeaders(l, r http.Header) http.Header {
+	out := http.Header{}
+
+	for k, v := range l {
+		out[k] = v
+	}
+
+	for k, vv := range r {
+		for _, v := range vv {
+			out.Add(k, v)
+		}
+	}
+
+	return out
+}
+
+func (h Middleware) filterProxiedHeaders(headers http.Header) http.Header {
+	filter := http.Header{}
+
+	for _, header := range proxiedHeaders {
+		if val, ok := headers[header]; ok {
+			filter[header] = val
+		}
+	}
+
+	return filter
+}
+
+var proxiedHeaders = []string{
+	"Accept-Encoding",
+	"Accept-Language",
+	"Cache-Control",
+	"Host",
+	"User-Agent",
+}