feat(03-03): add typed path params and per-plugin rollback

Compile regex and enum constraints at route registration so malformed and unknown IDs share a 404, and named rollback errors isolate one plugin's history.

Co-authored-by: Cursor <cursoragent@cursor.com>

surf/router.go

@@ -3,7 +3,6 @@ package surf
 import (
 	"fmt"
 	"net/http"
-	"strconv"
 	"strings"
 
 	"git.golem15.com/golem15/summercms/backpack"
@@ -23,11 +22,12 @@ type namedMiddleware struct {
 }
 
 type route struct {
-	pluginID   string
-	method     string
-	path       string
-	handler    http.Handler
-	middleware []string
+	pluginID    string
+	method      string
+	path        string
+	handler     http.Handler
+	middleware  []string
+	constraints []Constraint
 }
 
 // Router compiles group declarations onto net/http ServeMux.
@@ -128,6 +128,62 @@ func (g *Group) Get(path string, handler http.HandlerFunc, middleware ...string)
 	g.router.add(g.pluginID, g.prefix, g.middleware, path, handler, middleware)
 }
 
+// Where attaches a compiled regex constraint to the last route, matching PHP ->where().
+func (r *Router) Where(param, pattern string) {
+	if r == nil {
+		return
+	}
+	c, err := Regex(param, pattern)
+	if err != nil {
+		r.compileErr = err
+		return
+	}
+	r.addConstraint(c)
+}
+
+func (g *Group) Where(param, pattern string) {
+	if g == nil || g.router == nil {
+		return
+	}
+	g.router.Where(param, pattern)
+}
+
+// WhereIn attaches an allow-listed enum constraint to the last route.
+func (r *Router) WhereIn(param string, values ...string) {
+	if r == nil {
+		return
+	}
+	c, err := Enum(param, values...)
+	if err != nil {
+		r.compileErr = err
+		return
+	}
+	r.addConstraint(c)
+}
+
+func (g *Group) WhereIn(param string, values ...string) {
+	if g == nil || g.router == nil {
+		return
+	}
+	g.router.WhereIn(param, values...)
+}
+
+func (r *Router) addConstraint(c Constraint) {
+	if r.compileErr != nil {
+		return
+	}
+	if len(r.routes) == 0 {
+		r.compileErr = fmt.Errorf("surf: Where(%q) with no route", c.param)
+		return
+	}
+	last := &r.routes[len(r.routes)-1]
+	if !pathHasParam(last.path, c.param) {
+		r.compileErr = fmt.Errorf("surf: Where(%q) is not a path parameter of %s", c.param, last.path)
+		return
+	}
+	last.constraints = append(last.constraints, c)
+}
+
 func (r *Router) add(pluginID, prefix string, groupMW []string, path string, handler http.HandlerFunc, extra []string) {
 	full := joinPath(prefix, path)
 	key := "GET " + full
@@ -163,7 +219,7 @@ func (r *Router) compile() (http.Handler, error) {
 }
 
 func (r *Router) wrap(rt route) (http.Handler, error) {
-	h := rt.handler
+	h := constrain(rt.handler, rt.constraints)
 	h = noOpLimit(h)
 	h = orgSlot(h)
 	for i := len(rt.middleware) - 1; i >= 0; i-- {
@@ -290,23 +346,6 @@ func noOpLimit(next http.Handler) http.Handler {
 	return noopLimiter{}.Wrap(next)
 }
 
-// IntParam returns a positive integer path value. Missing or malformed ids
-// are false so callers can 404 both unknown and non-integer values.
-func IntParam(r *http.Request, name string) (int64, bool) {
-	if r == nil {
-		return 0, false
-	}
-	raw := r.PathValue(name)
-	if raw == "" {
-		return 0, false
-	}
-	n, err := strconv.ParseInt(raw, 10, 64)
-	if err != nil || n < 1 {
-		return 0, false
-	}
-	return n, true
-}
-
 func joinPath(prefix, path string) string {
 	prefix = strings.TrimSuffix(prefix, "/")
 	path = strings.TrimSpace(path)