From 43e2477e65de2e818af9250a20fd618d7f03f324 Mon Sep 17 00:00:00 2001
From: nrxr <nrxrco@gmail.com>
Date: Wed, 13 Nov 2019 21:26:30 -0400
Subject: [PATCH] net/url: add URL.Redacted() to return password-free string

Returning an URL.String() without the password is very useful for
situations where the URL is supposed to be logged and the password is
not useful to be shown.

This method re-uses URL.String() but with the password scrubbed and
substituted for a "xxxxx" in order to make it obvious that there was a
password. If the URL had no password then no "xxxxx" will be shown.

Fixes #34855
---
 src/net/url/url.go      | 10 ++++++
 src/net/url/url_test.go | 68 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/src/net/url/url.go b/src/net/url/url.go
index 6480d4b432242b..b8d712b1c4cf2f 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -821,6 +821,16 @@ func (u *URL) String() string {
 	return buf.String()
 }
 
+// Redacted is like String but redacts any password with "xxxxx".
+// Only the password in u.URL is redacted.
+func (u *URL) Redacted() string {
+	rdkt := *u
+	if _, has := rdkt.User.Password(); has {
+		rdkt.User = UserPassword(rdkt.User.Username(), "xxxxx")
+	}
+	return rdkt.String()
+}
+
 // Values maps a string key to a list of values.
 // It is typically used for query parameters and form values.
 // Unlike in the http.Header map, the keys in a Values map
diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
index 79fd3d5c79f37f..bb4660128a46b2 100644
--- a/src/net/url/url_test.go
+++ b/src/net/url/url_test.go
@@ -765,6 +765,74 @@ func TestURLString(t *testing.T) {
 	}
 }
 
+var maskedURLTestsPtr = []struct {
+	url        *URL
+	want       string
+	shouldMask bool
+}{
+	{
+		url: &URL{
+			Scheme: "http",
+			Host:   "host.tld",
+			Path:   "this:that",
+			User:   UserPassword("user", "password"),
+		},
+		want:       "http://user:xxxxx@host.tld/this:that",
+		shouldMask: true,
+	},
+	{
+		url: &URL{
+			Scheme: "http",
+			Host:   "host.tld",
+			Path:   "this:that",
+			User:   User("user"),
+		},
+		want:       "http://user@host.tld/this:that",
+		shouldMask: false,
+	},
+}
+
+var redactedURLTests = []struct {
+	url  *URL
+	want string
+}{
+	{
+		url: &URL{
+			Scheme: "http",
+			Host:   "host.tld",
+			Path:   "this:that",
+			User:   UserPassword("user", "password"),
+		},
+		want: "http://user:xxxxx@host.tld/this:that",
+	},
+	{
+		url: &URL{
+			Scheme: "http",
+			Host:   "host.tld",
+			Path:   "this:that",
+			User:   User("user"),
+		},
+		want: "http://user@host.tld/this:that",
+	},
+}
+
+func TestURLRedacted(t *testing.T) {
+	for _, tt := range redactedURLTests {
+		if got := tt.url.Redacted(); got != tt.want {
+			t.Errorf("%+v.Redacted() = %q; want %q", tt.url, got, tt.want)
+		}
+	}
+	for _, tt := range maskedURLTestsPtr {
+		if got := tt.url.Redacted(); got != tt.want {
+			t.Errorf("%+v.Redacted() = %q; want %q", tt.url, got, tt.want)
+		}
+
+		if tt.shouldMask && tt.url.Redacted() == tt.url.String() {
+			t.Errorf("%+v.Redacted() password should differ to %+v.String()", tt.url, tt.url)
+		}
+	}
+}
+
 type EscapeTest struct {
 	in  string
 	out string