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
+}

internal/reader/urlcleaner/urlcleaner_test.go

@@ -0,0 +1,108 @@
+// 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 (
+	"net/url"
+	"reflect"
+	"testing"
+)
+
+func TestRemoveTrackingParams(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "URL with tracking parameters",
+			input:    "https://example.com/page?id=123&utm_source=newsletter&utm_medium=email&fbclid=abc123",
+			expected: "https://example.com/page?id=123",
+		},
+		{
+			name:     "URL with only tracking parameters",
+			input:    "https://example.com/page?utm_source=newsletter&utm_medium=email",
+			expected: "https://example.com/page",
+		},
+		{
+			name:     "URL with no tracking parameters",
+			input:    "https://example.com/page?id=123&foo=bar",
+			expected: "https://example.com/page?id=123&foo=bar",
+		},
+		{
+			name:     "URL with no parameters",
+			input:    "https://example.com/page",
+			expected: "https://example.com/page",
+		},
+		{
+			name:     "URL with mixed case tracking parameters",
+			input:    "https://example.com/page?UTM_SOURCE=newsletter&utm_MEDIUM=email",
+			expected: "https://example.com/page",
+		},
+		{
+			name:     "URL with tracking parameters and fragments",
+			input:    "https://example.com/page?id=123&utm_source=newsletter#section1",
+			expected: "https://example.com/page?id=123#section1",
+		},
+		{
+			name:     "URL with only tracking parameters and fragments",
+			input:    "https://example.com/page?utm_source=newsletter#section1",
+			expected: "https://example.com/page#section1",
+		},
+		{
+			name:     "URL with only one tracking parameter",
+			input:    "https://example.com/page?utm_source=newsletter",
+			expected: "https://example.com/page",
+		},
+		{
+			name:     "URL with encoded characters",
+			input:    "https://example.com/page?name=John%20Doe&utm_source=newsletter",
+			expected: "https://example.com/page?name=John+Doe",
+		},
+		{
+			name:     "Invalid URL",
+			input:    "https://example|org/",
+			expected: "",
+		},
+		{
+			name:     "Non-HTTP URL",
+			input:    "mailto:user@example.org",
+			expected: "mailto:user@example.org",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := RemoveTrackingParameters(tt.input)
+			if tt.expected == "" {
+				if err == nil {
+					t.Errorf("Expected an error for invalid URL, but got none")
+				}
+			} else {
+				if err != nil {
+					t.Errorf("Unexpected error: %v", err)
+				}
+				if !urlsEqual(result, tt.expected) {
+					t.Errorf("removeTrackingParams(%q) = %q, want %q", tt.input, result, tt.expected)
+				}
+			}
+		})
+	}
+}
+
+// urlsEqual compares two URLs for equality, ignoring the order of query parameters
+func urlsEqual(url1, url2 string) bool {
+	u1, err1 := url.Parse(url1)
+	u2, err2 := url.Parse(url2)
+
+	if err1 != nil || err2 != nil {
+		return false
+	}
+
+	if u1.Scheme != u2.Scheme || u1.Host != u2.Host || u1.Path != u2.Path || u1.Fragment != u2.Fragment {
+		return false
+	}
+
+	return reflect.DeepEqual(u1.Query(), u2.Query())
+}