First commit

reader/rewrite/rewriter.go

@@ -0,0 +1,47 @@
+// Copyright 2017 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 rewrite
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/PuerkitoBio/goquery"
+)
+
+var rewriteRules = []func(string, string) string{
+	func(url, content string) string {
+		re := regexp.MustCompile(`youtube\.com/watch\?v=(.*)`)
+		matches := re.FindStringSubmatch(url)
+
+		if len(matches) == 2 {
+			video := `<iframe width="650" height="350" frameborder="0" src="https://www.youtube-nocookie.com/embed/` + matches[1] + `" allowfullscreen></iframe>`
+			return video + "<p>" + content + "</p>"
+		}
+		return content
+	},
+	func(url, content string) string {
+		if strings.HasPrefix(url, "https://xkcd.com") {
+			doc, err := goquery.NewDocumentFromReader(strings.NewReader(content))
+			if err != nil {
+				return content
+			}
+
+			imgTag := doc.Find("img").First()
+			if titleAttr, found := imgTag.Attr("title"); found {
+				return content + `<blockquote cite="` + url + `">` + titleAttr + "</blockquote>"
+			}
+		}
+		return content
+	},
+}
+
+func Rewriter(url, content string) string {
+	for _, rewriteRule := range rewriteRules {
+		content = rewriteRule(url, content)
+	}
+
+	return content
+}