feat: remove well-known URL parameter trackers

internal/reader/urlcleaner/urlcleaner.go

@@ -0,0 +1,96 @@
+// SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package urlcleaner // import "miniflux.app/v2/internal/reader/urlcleaner"
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+// Interesting lists:
+// https://raw.githubusercontent.com/AdguardTeam/AdguardFilters/master/TrackParamFilter/sections/general_url.txt
+// https://firefox.settings.services.mozilla.com/v1/buckets/main/collections/query-stripping/records
+var trackingParams = map[string]bool{
+	// https://en.wikipedia.org/wiki/UTM_parameters#Parameters
+	"utm_source":   true,
+	"utm_medium":   true,
+	"utm_campaign": true,
+	"utm_term":     true,
+	"utm_content":  true,
+
+	// Facebook Click Identifiers
+	"fbclid":    true,
+	"_openstat": true,
+
+	// Google Click Identifiers
+	"gclid":  true,
+	"dclid":  true,
+	"gbraid": true,
+	"wbraid": true,
+
+	// Yandex Click Identifiers
+	"yclid":  true,
+	"ysclid": true,
+
+	// Twitter Click Identifier
+	"twclid": true,
+
+	// Microsoft Click Identifier
+	"msclkid": true,
+
+	// Mailchimp Click Identifiers
+	"mc_cid": true,
+	"mc_eid": true,
+
+	// Wicked Reports click tracking
+	"wickedid": true,
+
+	// Hubspot Click Identifiers
+	"hsa_cam":       true,
+	"_hsenc":        true,
+	"__hssc":        true,
+	"__hstc":        true,
+	"__hsfp":        true,
+	"hsctatracking": true,
+
+	// Olytics
+	"rb_clickid":  true,
+	"oly_anon_id": true,
+	"oly_enc_id":  true,
+
+	// Vero Click Identifier
+	"vero_id": true,
+
+	// Marketo email tracking
+	"mkt_tok": true,
+}
+
+func RemoveTrackingParameters(inputURL string) (string, error) {
+	parsedURL, err := url.Parse(inputURL)
+	if err != nil {
+		return "", fmt.Errorf("urlcleaner: error parsing URL: %v", err)
+	}
+
+	if !strings.HasPrefix(parsedURL.Scheme, "http") {
+		return inputURL, nil
+	}
+
+	queryParams := parsedURL.Query()
+
+	// Remove tracking parameters
+	for param := range queryParams {
+		if trackingParams[strings.ToLower(param)] {
+			queryParams.Del(param)
+		}
+	}
+
+	parsedURL.RawQuery = queryParams.Encode()
+
+	// Remove trailing "?" if query string is empty
+	cleanedURL := parsedURL.String()
+	cleanedURL = strings.TrimSuffix(cleanedURL, "?")
+
+	return cleanedURL, nil
+}