general: add unit tests for >80% coverage

Includes a few minor fixes:
- frontend: support setting port for WHOIS server
- proxy: fix handling of very long lines
- proxy: refactor IP allowlist logic, parse allow IP list at startup

proxy/main_test.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/magiconair/properties/assert"
+)
+
+func TestHasAccessNotConfigured(t *testing.T) {
+	setting.allowedIPs = []net.IP{}
+	assert.Equal(t, hasAccess("whatever"), true)
+}
+
+func TestHasAccessAllowIPv4(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("1.2.3.4")}
+	assert.Equal(t, hasAccess("1.2.3.4:4321"), true)
+}
+
+func TestHasAccessDenyIPv4(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("4.3.2.1")}
+	assert.Equal(t, hasAccess("1.2.3.4:4321"), false)
+}
+
+func TestHasAccessAllowIPv6(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("2001:db8::1")}
+	assert.Equal(t, hasAccess("[2001:db8::1]:4321"), true)
+}
+
+func TestHasAccessAllowIPv6DifferentForm(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("2001:0db8::1")}
+	assert.Equal(t, hasAccess("[2001:db8::1]:4321"), true)
+}
+
+func TestHasAccessDenyIPv6(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("2001:db8::2")}
+	assert.Equal(t, hasAccess("[2001:db8::1]:4321"), false)
+}
+
+func TestHasAccessBadClientIP(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("1.2.3.4")}
+	assert.Equal(t, hasAccess("not an IP"), false)
+}
+
+func TestHasAccessBadClientIPPort(t *testing.T) {
+	setting.allowedIPs = []net.IP{net.ParseIP("1.2.3.4")}
+	assert.Equal(t, hasAccess("not an IP:not a port"), false)
+}
+
+func TestAccessHandlerAllow(t *testing.T) {
+	baseHandler := http.NotFoundHandler()
+	wrappedHandler := accessHandler(baseHandler)
+
+	r := httptest.NewRequest(http.MethodGet, "/mock", nil)
+	r.RemoteAddr = "1.2.3.4:4321"
+	w := httptest.NewRecorder()
+
+	setting.allowedIPs = []net.IP{net.ParseIP("1.2.3.4")}
+
+	wrappedHandler.ServeHTTP(w, r)
+	assert.Equal(t, w.Code, http.StatusNotFound)
+}
+
+func TestAccessHandlerDeny(t *testing.T) {
+	baseHandler := http.NotFoundHandler()
+	wrappedHandler := accessHandler(baseHandler)
+
+	r := httptest.NewRequest(http.MethodGet, "/mock", nil)
+	r.RemoteAddr = "1.2.3.4:4321"
+	w := httptest.NewRecorder()
+
+	setting.allowedIPs = []net.IP{net.ParseIP("4.3.2.1")}
+
+	wrappedHandler.ServeHTTP(w, r)
+	assert.Equal(t, w.Code, http.StatusInternalServerError)
+}