Use Accept request header instead of user agent to figure out non-browser clients. Funny fact, I borrowed the idea from a fork ('8a3e142cf3/router/generic.go (L33)')

README.md

@@ -47,7 +47,7 @@ curl -6 ifconfig.es
 ## Endpoints
 
 - https://ifconfig.es/
-- https://ifconfig.es/json
+- https://ifconfig.es/json (this is the same as `curl -H "Accept: application/json" https://ifconfig.es/`)
 - https://ifconfig.es/geo
   - https://ifconfig.es/geo/city
   - https://ifconfig.es/geo/country

integration-tests/integration_test.go

@@ -70,16 +70,18 @@ func TestContainerIntegration(t *testing.T) {
 	}()
 
 	http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
-	for _, url := range []string{"http://localhost:8000/json", "https://localhost:8001/json"} {
+	for _, url := range []string{"http://localhost:8000", "https://localhost:8001"} {
-		resp, _ := http.Get(url)
+		client := &http.Client{}
+		req, _ := http.NewRequest("GET", url, nil)
+		req.Header.Set("Accept", "application/json")
+		resp, _ := client.Do(req)
 		assert.Equal(t, 200, resp.StatusCode)
 
-		var dat router.JSONResponse
 		body, err := ioutil.ReadAll(resp.Body)
 		if err != nil {
 			log.Fatal(err)
 		}
 
-		assert.NoError(t, json.Unmarshal(body, &dat))
+		assert.NoError(t, json.Unmarshal(body, &router.JSONResponse{}))
 	}
 }

router/generic.go

@@ -4,7 +4,6 @@ import (
 	"net"
 	"net/http"
 	"path/filepath"
-	"regexp"
 
 	"github.com/dcarrillo/whatismyip/internal/httputils"
 	"github.com/dcarrillo/whatismyip/internal/setting"
@@ -12,8 +11,6 @@ import (
 	"github.com/gin-gonic/gin"
 )
 
-const userAgentPattern = `curl|wget|libwww-perl|python|ansible-httpget|HTTPie|WindowsPowerShell|http_request|Go-http-client|^$`
-
 // JSONResponse maps data as json
 type JSONResponse struct {
 	IP              string      `json:"ip"`
@@ -33,15 +30,17 @@ type JSONResponse struct {
 }
 
 func getRoot(ctx *gin.Context) {
-	reg := regexp.MustCompile(userAgentPattern)
+	switch ctx.NegotiateFormat(gin.MIMEPlain, gin.MIMEHTML, gin.MIMEJSON) {
-	if reg.Match([]byte(ctx.Request.UserAgent())) {
+	case gin.MIMEHTML:
-		ctx.String(http.StatusOK, ctx.ClientIP())
-	} else {
 		name := "home"
 		if setting.App.TemplatePath != "" {
 			name = filepath.Base(setting.App.TemplatePath)
 		}
 		ctx.HTML(http.StatusOK, name, jsonOutput(ctx))
+	case gin.MIMEJSON:
+		getJSON(ctx)
+	default:
+		ctx.String(http.StatusOK, ctx.ClientIP()+"\n")
 	}
 }
 

router/generic_test.go

@@ -9,31 +9,80 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestIP4RootFromCli(t *testing.T) {
+func TestRootContentType(t *testing.T) {
-	uas := []string{
+	tests := []struct {
-		"",
+		name     string
-		"curl",
+		accepted string
-		"wget",
+		expected string
-		"libwww-perl",
+	}{
-		"python",
+		{
-		"ansible-httpget",
+			name:     "Accept wildcard",
-		"HTTPie",
+			accepted: "*/*",
-		"WindowsPowerShell",
+			expected: contentType.text,
-		"http_request",
+		},
-		"Go-http-client",
+		{
+			name:     "Bogus accept",
+			accepted: "bogus/plain",
+			expected: contentType.text,
+		},
+		{
+			name:     "Accept plain text",
+			accepted: "text/plain",
+			expected: contentType.text,
+		},
+		{
+			name:     "Accept json",
+			accepted: "application/json",
+			expected: contentType.json,
+		},
 	}
-
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
 			req, _ := http.NewRequest("GET", "/", nil)
-	req.Header.Set("X-Real-IP", testIP.ipv4)
+			req.Header.Set(trustedHeader, testIP.ipv4)
-
+			req.Header.Set("Accept", tt.accepted)
-	for _, ua := range uas {
-		req.Header.Set("User-Agent", ua)
 
 			w := httptest.NewRecorder()
 			app.ServeHTTP(w, req)
 
 			assert.Equal(t, 200, w.Code)
-		assert.Equal(t, testIP.ipv4, w.Body.String())
+			assert.Equal(t, tt.expected, w.Header().Get("Content-Type"))
+		})
+	}
+}
+
+func TestGetIP(t *testing.T) {
+	expected := testIP.ipv4 + "\n"
+	tests := []struct {
+		name     string
+		accepted string
+	}{
+		{
+			name:     "No browser",
+			accepted: "*/*",
+		},
+		{
+			name:     "Bogus accept",
+			accepted: "bogus/plain",
+		},
+		{
+			name:     "Plain accept",
+			accepted: "text/plain",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req, _ := http.NewRequest("GET", "/", nil)
+			req.Header.Set(trustedHeader, testIP.ipv4)
+			req.Header.Set("Accept", tt.accepted)
+
+			w := httptest.NewRecorder()
+			app.ServeHTTP(w, req)
+
+			assert.Equal(t, 200, w.Code)
+			assert.Equal(t, expected, w.Body.String())
+			assert.Equal(t, contentType.text, w.Header().Get("Content-Type"))
+		})
 	}
 }
 
@@ -50,7 +99,7 @@ func TestHost(t *testing.T) {
 func TestClientPort(t *testing.T) {
 	req, _ := http.NewRequest("GET", "/client-port", nil)
 	req.RemoteAddr = net.JoinHostPort(testIP.ipv4, "1000")
-	req.Header.Set("X-Real-IP", testIP.ipv4)
+	req.Header.Set(trustedHeader, testIP.ipv4)
 
 	w := httptest.NewRecorder()
 	app.ServeHTTP(w, req)
@@ -71,31 +120,44 @@ func TestNotFound(t *testing.T) {
 }
 
 func TestJSON(t *testing.T) {
-	expectedIPv4 := `{"client_port":"1000","ip":"81.2.69.192","ip_version":4,"country":"United Kingdom","country_code":"GB","city":"London","latitude":51.5142,"longitude":-0.0931,"postal_code":"","time_zone":"Europe/London","asn":0,"asn_organization":"","host":"test","headers":{"X-Real-Ip":["81.2.69.192"]}}`
+	type args struct {
-	expectedIPv6 := `{"asn":3352, "asn_organization":"TELEFONICA DE ESPANA", "city":"", "client_port":"1000", "country":"", "country_code":"", "headers":{"X-Real-Ip":["2a02:9000::1"]}, "host":"test", "ip":"2a02:9000::1", "ip_version":6, "latitude":0, "longitude":0, "postal_code":"", "time_zone":""}`
+		ip string
-
+	}
+	tests := []struct {
+		name     string
+		args     args
+		expected string
+	}{
+		{
+			name: "IPv4",
+			args: args{
+				ip: testIP.ipv4,
+			},
+			expected: jsonIPv4,
+		},
+		{
+			name: "IPv6",
+			args: args{
+				ip: testIP.ipv6,
+			},
+			expected: jsonIPv6,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
 			req, _ := http.NewRequest("GET", "/json", nil)
-	req.RemoteAddr = net.JoinHostPort(testIP.ipv4, "1000")
+			req.RemoteAddr = net.JoinHostPort(tt.args.ip, "1000")
 			req.Host = "test"
-	req.Header.Set("X-Real-IP", testIP.ipv4)
+			req.Header.Set(trustedHeader, tt.args.ip)
 
 			w := httptest.NewRecorder()
 			app.ServeHTTP(w, req)
 
 			assert.Equal(t, 200, w.Code)
 			assert.Equal(t, contentType.json, w.Header().Get("Content-Type"))
-	assert.JSONEq(t, expectedIPv4, w.Body.String())
+			assert.JSONEq(t, tt.expected, w.Body.String())
-
+		})
-	req.RemoteAddr = net.JoinHostPort(testIP.ipv6, "1000")
+	}
-	req.Host = "test"
-	req.Header.Set("X-Real-IP", testIP.ipv6)
-
-	w = httptest.NewRecorder()
-	app.ServeHTTP(w, req)
-
-	assert.Equal(t, 200, w.Code)
-	assert.Equal(t, contentType.json, w.Header().Get("Content-Type"))
-	assert.JSONEq(t, expectedIPv6, w.Body.String())
 }
 
 func TestAll(t *testing.T) {
@@ -120,7 +182,7 @@ X-Real-Ip: 81.2.69.192
 	req, _ := http.NewRequest("GET", "/all", nil)
 	req.RemoteAddr = net.JoinHostPort(testIP.ipv4, "1000")
 	req.Host = "test"
-	req.Header.Set("X-Real-IP", testIP.ipv4)
+	req.Header.Set(trustedHeader, testIP.ipv4)
 	req.Header.Set("Header1", "one")
 
 	w := httptest.NewRecorder()

router/setup_test.go

@@ -16,6 +16,7 @@ type testIPs struct {
 }
 
 type contentTypes struct {
+	html string
 	text string
 	json string
 }
@@ -29,9 +30,12 @@ var (
 		ipv6ASN: "2a02:a800::1",
 	}
 	contentType = contentTypes{
+		html: "content-type: text/html; charset=utf-8",
 		text: "text/plain; charset=utf-8",
 		json: "application/json; charset=utf-8",
 	}
+	jsonIPv4 = `{"client_port":"1000","ip":"81.2.69.192","ip_version":4,"country":"United Kingdom","country_code":"GB","city":"London","latitude":51.5142,"longitude":-0.0931,"postal_code":"","time_zone":"Europe/London","asn":0,"asn_organization":"","host":"test","headers":{"X-Real-Ip":["81.2.69.192"]}}`
+	jsonIPv6 = `{"asn":3352, "asn_organization":"TELEFONICA DE ESPANA", "city":"", "client_port":"1000", "country":"", "country_code":"", "headers":{"X-Real-Ip":["2a02:9000::1"]}, "host":"test", "ip":"2a02:9000::1", "ip_version":6, "latitude":0, "longitude":0, "postal_code":"", "time_zone":""}`
 )
 
 const trustedHeader = "X-Real-IP"