model: redirect mappings (RedirectTo, RedirectPermanent, RedirectKeepPath)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

model/model.go

@@ -1,7 +1,10 @@
 // Package model holds the types shared by hammerhead, blacktip and bamboo.
 package model
 
-import "time"
+import (
+	"strings"
+	"time"
+)
 
 const (
 	ProtoTCP   = "tcp"   // raw TCP on ip:port
@@ -19,6 +22,21 @@ func (m Mapping) LastPort() int {
 	return m.Port
 }
 
+// IsRedirect reports whether the mapping answers with a redirect instead of forwarding to a target.
+func (m Mapping) IsRedirect() bool { return m.RedirectTo != "" }
+
+// RedirectLocation is where a request for requestURI (path and query) is sent. With KeepPath the
+// request's path and query follow the destination, so example.com/a?b=1 goes to to/a?b=1.
+func (m Mapping) RedirectLocation(requestURI string) string {
+	if !m.RedirectKeepPath {
+		return m.RedirectTo
+	}
+	if requestURI == "" || requestURI[0] != '/' {
+		requestURI = "/" + requestURI
+	}
+	return strings.TrimRight(m.RedirectTo, "/") + requestURI
+}
+
 // HostBased reports whether mappings of this protocol are routed by hostname.
 func HostBased(proto string) bool {
 	return proto == ProtoHTTP || proto == ProtoHTTPS || proto == ProtoTLS
@@ -63,7 +81,7 @@ type Site struct {
 
 	Tags []string `json:"tags,omitempty"` // labels for grouping and filtering in the dashboard
 
-	TunnelIP string `json:"tunnelIp,omitempty"`  // the site's address inside the tunnel network
+	TunnelIP  string `json:"tunnelIp,omitempty"`  // the site's address inside the tunnel network
 	PublicKey string `json:"publicKey,omitempty"` // WireGuard public key, reported by the agent
 
 	// Version is the release the program reports (e.g. v0.1.5). AutoUpdate says whether it may update
@@ -132,6 +150,12 @@ type Mapping struct {
 	// target with a PROXY protocol header carrying the real client address.
 	ProxyProtocol string `json:"proxyProtocol,omitempty"`
 
+	// A web mapping with RedirectTo set sends visitors there instead of to a target (so it has no
+	// targets, login or health checks). It answers 301 when RedirectPermanent, otherwise 302.
+	RedirectTo        string `json:"redirectTo,omitempty"`
+	RedirectPermanent bool   `json:"redirectPermanent,omitempty"`
+	RedirectKeepPath  bool   `json:"redirectKeepPath,omitempty"`
+
 	// web (http/https) options
 	Auth          Auth   `json:"auth"`
 	AuthEpoch     int64  `json:"authEpoch"` // bumped to sign every visitor out; set by hammerhead only

model/model_test.go

@@ -0,0 +1,25 @@
+package model
+
+import "testing"
+
+func TestRedirectLocation(t *testing.T) {
+	cases := []struct {
+		m    Mapping
+		uri  string
+		want string
+	}{
+		{Mapping{RedirectTo: "https://new.example.com"}, "/a?b=1", "https://new.example.com"},
+		{Mapping{RedirectTo: "https://new.example.com", RedirectKeepPath: true}, "/a?b=1", "https://new.example.com/a?b=1"},
+		{Mapping{RedirectTo: "https://new.example.com/", RedirectKeepPath: true}, "/", "https://new.example.com/"},
+		{Mapping{RedirectTo: "https://new.example.com/base", RedirectKeepPath: true}, "/x/y", "https://new.example.com/base/x/y"},
+		{Mapping{RedirectTo: "https://new.example.com", RedirectKeepPath: true}, "", "https://new.example.com/"},
+	}
+	for _, c := range cases {
+		if got := c.m.RedirectLocation(c.uri); got != c.want {
+			t.Errorf("%+v %q: got %q, want %q", c.m, c.uri, got, c.want)
+		}
+	}
+	if (Mapping{}).IsRedirect() || !(Mapping{RedirectTo: "https://x"}).IsRedirect() {
+		t.Error("IsRedirect is wrong")
+	}
+}