Proxy support for several media types

closes #615
closes #635

proxy/media_proxy.go

@@ -0,0 +1,123 @@
+// Copyright 2020 Frédéric Guillot. All rights reserved.
+// Use of this source code is governed by the Apache 2.0
+// license that can be found in the LICENSE file.
+
+package proxy // import "miniflux.app/proxy"
+
+import (
+	"strings"
+
+	"miniflux.app/config"
+	"miniflux.app/reader/sanitizer"
+	"miniflux.app/url"
+
+	"github.com/PuerkitoBio/goquery"
+	"github.com/gorilla/mux"
+)
+
+type urlProxyRewriter func(router *mux.Router, url string) string
+
+// ProxyRewriter replaces media URLs with internal proxy URLs.
+func ProxyRewriter(router *mux.Router, data string) string {
+	return genericProxyRewriter(router, ProxifyURL, data)
+}
+
+// AbsoluteProxyRewriter do the same as ProxyRewriter except it uses absolute URLs.
+func AbsoluteProxyRewriter(router *mux.Router, host, data string) string {
+	proxifyFunction := func(router *mux.Router, url string) string {
+		return AbsoluteProxifyURL(router, host, url)
+	}
+	return genericProxyRewriter(router, proxifyFunction, data)
+}
+
+func genericProxyRewriter(router *mux.Router, proxifyFunction urlProxyRewriter, data string) string {
+	proxyOption := config.Opts.ProxyOption()
+	if proxyOption == "none" {
+		return data
+	}
+
+	doc, err := goquery.NewDocumentFromReader(strings.NewReader(data))
+	if err != nil {
+		return data
+	}
+
+	for _, mediaType := range config.Opts.ProxyMediaTypes() {
+		switch mediaType {
+		case "image":
+			doc.Find("img").Each(func(i int, img *goquery.Selection) {
+				if srcAttrValue, ok := img.Attr("src"); ok {
+					if !isDataURL(srcAttrValue) && (proxyOption == "all" || !url.IsHTTPS(srcAttrValue)) {
+						img.SetAttr("src", proxifyFunction(router, srcAttrValue))
+					}
+				}
+
+				if srcsetAttrValue, ok := img.Attr("srcset"); ok {
+					proxifySourceSet(img, router, proxifyFunction, proxyOption, srcsetAttrValue)
+				}
+			})
+
+			doc.Find("picture source").Each(func(i int, sourceElement *goquery.Selection) {
+				if srcsetAttrValue, ok := sourceElement.Attr("srcset"); ok {
+					proxifySourceSet(sourceElement, router, proxifyFunction, proxyOption, srcsetAttrValue)
+				}
+			})
+
+		case "audio":
+			doc.Find("audio").Each(func(i int, audio *goquery.Selection) {
+				if srcAttrValue, ok := audio.Attr("src"); ok {
+					if !isDataURL(srcAttrValue) && (proxyOption == "all" || !url.IsHTTPS(srcAttrValue)) {
+						audio.SetAttr("src", proxifyFunction(router, srcAttrValue))
+					}
+				}
+			})
+
+			doc.Find("audio source").Each(func(i int, sourceElement *goquery.Selection) {
+				if srcAttrValue, ok := sourceElement.Attr("src"); ok {
+					if !isDataURL(srcAttrValue) && (proxyOption == "all" || !url.IsHTTPS(srcAttrValue)) {
+						sourceElement.SetAttr("src", proxifyFunction(router, srcAttrValue))
+					}
+				}
+			})
+
+		case "video":
+			doc.Find("video").Each(func(i int, video *goquery.Selection) {
+				if srcAttrValue, ok := video.Attr("src"); ok {
+					if !isDataURL(srcAttrValue) && (proxyOption == "all" || !url.IsHTTPS(srcAttrValue)) {
+						video.SetAttr("src", proxifyFunction(router, srcAttrValue))
+					}
+				}
+			})
+
+			doc.Find("video source").Each(func(i int, sourceElement *goquery.Selection) {
+				if srcAttrValue, ok := sourceElement.Attr("src"); ok {
+					if !isDataURL(srcAttrValue) && (proxyOption == "all" || !url.IsHTTPS(srcAttrValue)) {
+						sourceElement.SetAttr("src", proxifyFunction(router, srcAttrValue))
+					}
+				}
+			})
+		}
+	}
+
+	output, err := doc.Find("body").First().Html()
+	if err != nil {
+		return data
+	}
+
+	return output
+}
+
+func proxifySourceSet(element *goquery.Selection, router *mux.Router, proxifyFunction urlProxyRewriter, proxyOption, srcsetAttrValue string) {
+	imageCandidates := sanitizer.ParseSrcSetAttribute(srcsetAttrValue)
+
+	for _, imageCandidate := range imageCandidates {
+		if !isDataURL(imageCandidate.ImageURL) && (proxyOption == "all" || !url.IsHTTPS(imageCandidate.ImageURL)) {
+			imageCandidate.ImageURL = proxifyFunction(router, imageCandidate.ImageURL)
+		}
+	}
+
+	element.SetAttr("srcset", imageCandidates.String())
+}
+
+func isDataURL(s string) bool {
+	return strings.HasPrefix(s, "data:")
+}