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
+}

reader/rewrite/rewriter_test.go

@@ -0,0 +1,34 @@
+// 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 "testing"
+
+func TestRewriteWithNoMatchingRule(t *testing.T) {
+	output := Rewriter("https://example.org/article", `Some text.`)
+	expected := `Some text.`
+
+	if expected != output {
+		t.Errorf(`Not expected output: got "%s" instead of "%s"`, output, expected)
+	}
+}
+
+func TestRewriteWithYoutubeLink(t *testing.T) {
+	output := Rewriter("https://www.youtube.com/watch?v=1234", `Video Description`)
+	expected := `<iframe width="650" height="350" frameborder="0" src="https://www.youtube-nocookie.com/embed/1234" allowfullscreen></iframe><p>Video Description</p>`
+
+	if expected != output {
+		t.Errorf(`Not expected output: got "%s" instead of "%s"`, output, expected)
+	}
+}
+
+func TestRewriteWithXkcdLink(t *testing.T) {
+	description := `<img src="https://imgs.xkcd.com/comics/thermostat.png" title="Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you." alt="Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you." />`
+	output := Rewriter("https://xkcd.com/1912/", description)
+	expected := description + `<blockquote cite="https://xkcd.com/1912/">Your problem is so terrible, I worry that, if I help you, I risk drawing the attention of whatever god of technology inflicted it on you.</blockquote>`
+	if expected != output {
+		t.Errorf(`Not expected output: got "%s" instead of "%s"`, output, expected)
+	}
+}