1 files changed, 168 insertions, 0 deletions
diff --git a/helper.go b/helper.go
new file mode 100644
index 0000000..af5f4c1
--- /dev/null
+++ b/helper.go
@@ -0,0 +1,168 @@
+package main
+
+import (
+	_url "net/url"
+	"strings"
+	log "github.com/sirupsen/logrus"
+	"regexp"
+)
+
+func stripHNPrefix(title string) string {
+	title = strings.TrimPrefix(title, "Ask HN:")
+	title = strings.TrimPrefix(title, "Show HN:")
+	title = strings.TrimPrefix(title, "Tell HN:")
+	title = strings.TrimPrefix(title, "Experiment HN:")
+	title = strings.TrimPrefix(title, "Launch HN:")
+
+	return strings.TrimSpace(title)
+}
+
+/**
+ * removes given param from URL
+ */
+func _removeParam(url, key string) string {
+	u, err := _url.Parse(url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	q := u.Query()
+	q.Del(key)
+	u.RawQuery  = q.Encode()
+	return u.String()
+}
+
+func normalizeUrl(url string) string {
+	match, err := regexp.MatchString("^http://", url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if match {
+		log.Debug("normalize: ", "http:// ", url)
+		r := regexp.MustCompile("^http://")
+		url = r.ReplaceAllString(url, "https://")
+	}
+
+	// add missing https:// if no scheme
+	u, err := _url.Parse(url)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	if "" == u.Scheme {
+		if strings.HasPrefix(url, "/") {
+			url = "https:" + url
+		} else {
+			url = "https://" + url
+		}
+	}
+
+
+	match, err = regexp.MatchString("youtube://", url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if match {
+		r := regexp.MustCompile("youtube://")
+		url = r.ReplaceAllString(url, "https://")
+	}
+
+	match, err = regexp.MatchString("youtu.be/", url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if match {
+		log.Debug("normalize: ", "youtu.be ", url)
+
+		/**
+		 * remove tracking param "si"
+		 */
+		url = _removeParam(url, "si")
+		url = _removeParam(url, "feature")
+
+		u, err := _url.Parse(url)
+		if err != nil {
+			log.Fatal(err)
+		}
+		q := u.Query()
+		q.Add("v", strings.TrimLeft(u.Path, "/"))
+
+		u.Host = "www.youtube.com"
+		u.Path = "watch"
+
+		u.RawQuery = q.Encode()
+		url = u.String()
+		
+		//r := regexp.MustCompile("youtu.be/")
+		//url = r.ReplaceAllString(url, "youtube.com/watch?v=")
+	}
+
+	match, err = regexp.MatchString("/m.youtube.com/", url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if match {
+		log.Debug("normalize: ", "m.youtube.com ", url)
+
+		/**
+		 * remove tracking param "si"
+		 */
+		url = _removeParam(url, "si")
+		url = _removeParam(url, "feature")
+
+		r := regexp.MustCompile("/m.youtube.com/")
+		url = r.ReplaceAllString(url, "/www.youtube.com/")
+	}
+
+	match, err = regexp.MatchString("/m.imdb.com/", url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if match {
+		log.Debug("normalize: ", "m.imdb.com ", url)
+
+		/**
+		 * remove tracking param "si"
+		 */
+		url = _removeParam(url, "si")
+		url = _removeParam(url, "feature")
+
+		r := regexp.MustCompile("/m.imdb.com/")
+		url = r.ReplaceAllString(url, "/www.imdb.com")
+	}
+
+	/*
+	match, err = regexp.MatchString("m.wikipedia.org", url)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if match {
+		r := regexp.MustCompile("m.wikipedia.org")
+		url = r.ReplaceAllString(url, "wikipedia.org")
+	}
+	*/
+
+	/**
+	 * remove tracking utm_ params
+	 */
+	url = _removeParam(url, "utm_source")
+	url = _removeParam(url, "utm_medium")
+	url = _removeParam(url, "utm_campaign")
+	url = _removeParam(url, "utm_term")
+	url = _removeParam(url, "utm_content")
+
+	u, err = _url.Parse(url)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	/**
+	 * Append www. to normalize URL. exclude relative URLs starting with // since this is not recognized by Go
+	 * Screw that, wierd edge case. Someone pasted a
+	 */
+	if ! strings.HasPrefix(u.Host, "www.") {
+		u.Host = "www." + u.Host
+	}
+	url = u.String()
+
+	return url
+}