From 4577ec34c103b0a7c40b0606602aa2f7918a403d Mon Sep 17 00:00:00 2001
From: Martin Dosch <spam-debian-salsa@mdosch.de>
Date: Fri, 3 Aug 2018 11:02:31 +0200
Subject: [PATCH] Added function to remove some commonly used tracking.

---
 getarticles.go    |  8 +++++++-
 removetracking.go | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 removetracking.go

diff --git a/getarticles.go b/getarticles.go
index 7d039e1..f8d4949 100644
--- a/getarticles.go
+++ b/getarticles.go
@@ -193,16 +193,22 @@ func getArticles(feedURL string, max int) (string, error) {
 			}
 		}
 
+		// Remove redirects and tracking parameters from URL.
+		cleanURL, _ := removeTracking(article.Link)
+
 		// Strip HTML as we want to get plain text.
 		description, err := html2text.FromString(article.Description)
 		if err != nil {
 			return "", err
 		}
 
+		// Only append article link if it is not yet contained in description (e.g. read more: URL).
 		if strings.Contains(description, article.Link) == true {
+			// Replace article link with URL cleaned from redirects and trackers.
+			description = strings.Replace(description, article.Link, cleanURL, -1)
 			output = output + feed.Title + ": *" + article.Title + "*\n\n" + description
 		} else {
-			output = output + feed.Title + ": *" + article.Title + "*\n\n" + description + "\n" + article.Link
+			output = output + feed.Title + ": *" + article.Title + "*\n\n" + description + "\n" + cleanURL
 		}
 
 		if i > 0 {
diff --git a/removetracking.go b/removetracking.go
new file mode 100644
index 0000000..a3179a3
--- /dev/null
+++ b/removetracking.go
@@ -0,0 +1,34 @@
+/* Copyright 2018 Martin Dosch
+Licensed under the "MIT License" */
+
+package main
+
+import (
+	"net/http"
+	"strings"
+)
+
+// Remove tracking parameter from URLs
+func removeTracking(input string) (output string, err error) {
+
+	// Perfom a get request to get rid of 301 forwarding through
+	// services like feedproxy.google.com.
+	resp, err := http.Get(input)
+	if err != nil {
+		return input, err
+	}
+
+	// Remove the URL part starting with "?utm_", which is
+	// used for tracking purposes.
+	output = strings.Split(resp.Request.URL.String(), "?utm_")[0]
+
+	// Remove the URL part starting with "?wt_", which is
+	// used for Webtrekk tracking.
+	output = strings.Split(output, "?wt_")[0]
+
+	// Remove the URL part starting with "#ref=", which is
+	// used for tracking the referer by some feeds.
+	output = strings.Split(output, "#ref=")[0]
+
+	return output, err
+}