feat(publicip): add changeip ipv4v6 echo service

README.md

@@ -290,6 +290,7 @@ You can otherwise customize it with the following:
   - `nnev` using [https://ip.nnev.de](https://ip.nnev.de)
   - `wtfismyip` using [https://wtfismyip.com/text](https://wtfismyip.com/text)
   - `seeip` using [https://api.seeip.org](https://api.seeip.org)
+  - `changeip` using [https://ip.changeip.com](https://ip.changeip.com)
   - You can also specify an HTTPS URL with prefix `url:` for example `url:https://ipinfo.io/ip`
 - `PUBLICIPV4_HTTP_PROVIDERS` gets your public IPv4 address only. It can be one or more of the following:
   - `ipleak` using [https://ipv4.ipleak.net/json](https://ipv4.ipleak.net/json)

pkg/ipextract/ipextract.go

@@ -26,6 +26,7 @@ func IPv6(text string) (addresses []netip.Addr) {
 }
 
 func extract(text string, alphabet string) (addresses []netip.Addr) {
+	addressesSeen := make(map[netip.Addr]struct{})
 	var start, end int
 	for {
 		for i := start; i < len(text); i++ {
@@ -39,7 +40,11 @@ func extract(text string, alphabet string) (addresses []netip.Addr) {
 		possibleIPString := text[start:end]
 		ipAddress, err := netip.ParseAddr(possibleIPString)
 		if err == nil { // Valid IP address found
-			addresses = append(addresses, ipAddress)
+			_, seen := addressesSeen[ipAddress]
+			if !seen {
+				addressesSeen[ipAddress] = struct{}{}
+				addresses = append(addresses, ipAddress)
+			}
 		}
 
 		if end == len(text) {

pkg/publicip/http/fetch_test.go

@@ -85,14 +85,14 @@ func Test_fetch(t *testing.T) {
 			ctx:         context.Background(),
 			url:         "https://opendns.com/ip",
 			version:     ipversion.IP4or6,
-			httpContent: []byte(`1.67.201.251 1.67.201.251`),
+			httpContent: []byte(`1.67.201.251 1.67.201.252`),
 			err:         errors.New("too many IP addresses: found 2 IPv4 addresses instead of 1"),
 		},
 		"too many IPv6s for IP4or6": {
 			ctx:         context.Background(),
 			url:         "https://opendns.com/ip",
 			version:     ipversion.IP4or6,
-			httpContent: []byte(`::1 ::1`),
+			httpContent: []byte(`::1 ::2`),
 			err:         errors.New("too many IP addresses: found 2 IPv6 addresses instead of 1"),
 		},
 		"no IP for IP4": {
@@ -113,7 +113,7 @@ func Test_fetch(t *testing.T) {
 			ctx:         context.Background(),
 			url:         "https://opendns.com/ip",
 			version:     ipversion.IP4,
-			httpContent: []byte(`1.67.201.251 1.67.201.251`),
+			httpContent: []byte(`1.67.201.251 1.67.201.252`),
 			err:         errors.New("too many IP addresses: found 2 IPv4 addresses instead of 1"),
 		},
 		"no IP for IP6": {
@@ -137,7 +137,7 @@ func Test_fetch(t *testing.T) {
 			ctx:         context.Background(),
 			url:         "https://opendns.com/ip",
 			version:     ipversion.IP6,
-			httpContent: []byte(`::1 ::1`),
+			httpContent: []byte(`::1 ::2`),
 			err:         errors.New("too many IP addresses: found 2 IPv6 addresses instead of 1"),
 		},
 	}

pkg/publicip/http/providers.go

@@ -23,6 +23,7 @@ const (
 	Nnev      Provider = "nnev"
 	Wtfismyip Provider = "wtfismyip"
 	Seeip     Provider = "seeip"
+	Changeip  Provider = "changeip"
 )
 
 func ListProviders() []Provider {
@@ -38,6 +39,7 @@ func ListProviders() []Provider {
 		Nnev,
 		Wtfismyip,
 		Seeip,
+		Changeip,
 	}
 }
 
@@ -136,6 +138,8 @@ func (provider Provider) url(version ipversion.IPVersion) (url string, ok bool)
 			url = "https://wtfismyip.com/text"
 		case Seeip:
 			url = "https://api.seeip.org"
+		case Changeip:
+			url = "https://ip.changeip.com"
 		}
 	}
 

pkg/publicip/http/providers_test.go

@@ -20,7 +20,7 @@ func Test_ListProvidersForVersion(t *testing.T) {
 		"ip4or6": {
 			version: ipversion.IP4or6,
 			providers: []Provider{Google, Ifconfig, Ipify, Ipinfo, Spdyn, Ipleak,
-				Icanhazip, Ident, Nnev, Wtfismyip, Seeip},
+				Icanhazip, Ident, Nnev, Wtfismyip, Seeip, Changeip},
 		},
 		"ip4": {
 			version:   ipversion.IP4,