fix(setup): root empty-prefix static assets

setup.go

@@ -23,11 +23,8 @@ type SetupFunc = func(jw *Jaws, handleFn HandleFunc, prefix string) (urls []*url
 
 // makeAbsPath returns a copy of u with prefix prepended to relative paths.
 //
-// When a non-empty prefix is applied the result is made absolute (a leading slash is
-// ensured), so the head URL matches the always-absolute handler pattern that
-// [staticserve.NormalizeGET] registers for a [staticserve.StaticServe] extra. A
-// relative prefix would otherwise leave the URL relative, which a browser resolves
-// against the current page and so fails to load on any non-root page.
+// When a non-empty prefix is applied, the joined path is slash-rooted. An empty
+// prefix preserves a relative URL.
 func makeAbsPath(prefix string, u *url.URL) *url.URL {
 	if u != nil {
 		copied := *u
@@ -48,6 +45,13 @@ func makeAbsPath(prefix string, u *url.URL) *url.URL {
 // It calls [Jaws.GenerateHeadHTML] with the final list of URLs, with any
 // relative URL paths prefixed with prefix.
 //
+// [staticserve.StaticServe] extras are local resources. Their generated URLs
+// are slash-rooted so they match their registered handlers, including when
+// prefix is empty. Other relative URL extras remain relative with an empty
+// prefix. Each [staticserve.StaticServe.Name] is treated as a literal path,
+// not as a pre-escaped URL; percent signs in a name are escaped as literal
+// percent signs.
+//
 // If handleFn is nil, Setup generates head HTML from the configured resources
 // without registering any handlers.
 func (jw *Jaws) Setup(handleFn HandleFunc, prefix string, extras ...any) (err error) {
@@ -59,14 +63,14 @@ func (jw *Jaws) Setup(handleFn HandleFunc, prefix string, extras ...any) (err er
 
 	handleStaticServe := func(ss *staticserve.StaticServe) {
 		if ss != nil {
-			u, urlErr := url.Parse(ss.Name)
-			err = errors.Join(err, urlErr)
-			if u != nil {
-				u = makeAbsPath(prefix, u)
-				urls = append(urls, u)
-				if handleFn != nil {
-					setupHandleFn(staticserve.NormalizeGET(u.String()), ss)
-				}
+			assetPath := ss.Name
+			if !path.IsAbs(assetPath) {
+				assetPath = path.Join(prefix, assetPath)
+			}
+			u := &url.URL{Path: path.Join("/", assetPath)}
+			urls = append(urls, u)
+			if handleFn != nil {
+				setupHandleFn(staticserve.NormalizeGET(u.String()), ss)
 			}
 		}
 	}

setup_test.go

@@ -2,6 +2,7 @@ package jaws
 
 import (
 	"net/http"
+	"net/http/httptest"
 	"net/url"
 	"path"
 	"strings"
@@ -182,22 +183,133 @@ func TestJaws_SetupDoesNotPrefixProtocolRelativeURL(t *testing.T) {
 func TestJaws_SetupEmptyPrefix(t *testing.T) {
 	ss := staticserve.Must("favicon.png", []byte("Hello"))
 
-	jw, _ := New()
+	jw, err := New()
+	if err != nil {
+		t.Fatal(err)
+	}
 	defer jw.Close()
-	mux := &testMux{}
-	_ = jw.Setup(mux.Handle, "", ss)
+	mux := http.NewServeMux()
+	if err = jw.Setup(mux.Handle, "", ss); err != nil {
+		t.Fatal(err)
+	}
 
-	if got := jw.FaviconURL(); got != ss.Name {
-		t.Errorf("unexpected favicon URL: %q", got)
+	headURL := jw.FaviconURL()
+	if want := "/" + ss.Name; headURL != want {
+		t.Fatalf("favicon URL = %q, want %q", headURL, want)
 	}
-	if len(mux.m) != 1 {
-		t.Fatalf("expected 1 handler, got %d", len(mux.m))
+	if !strings.Contains(jw.headPrefix, `href="`+headURL+`"`) {
+		t.Fatalf("head HTML %q does not contain favicon URL %q", jw.headPrefix, headURL)
 	}
-	for pattern := range mux.m {
-		if want := "GET /" + ss.Name; pattern != want {
-			t.Errorf("expected pattern %q, got %q", want, pattern)
+
+	pageURL, err := url.Parse("http://example.test/account/view")
+	if err != nil {
+		t.Fatal(err)
+	}
+	ref, err := url.Parse(headURL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	resolved := pageURL.ResolveReference(ref)
+	if resolved.Path != headURL {
+		t.Fatalf("favicon URL %q resolves from nested page to %q", headURL, resolved.Path)
+	}
+
+	rr := httptest.NewRecorder()
+	mux.ServeHTTP(rr, httptest.NewRequest(http.MethodGet, resolved.String(), nil))
+	if rr.Code != http.StatusOK {
+		t.Fatalf("GET %q = %d, want %d", resolved.Path, rr.Code, http.StatusOK)
+	}
+	if got := rr.Body.String(); got != "Hello" {
+		t.Fatalf("GET %q body = %q, want %q", resolved.Path, got, "Hello")
+	}
+}
+
+func TestJaws_SetupStaticServeEscapesName(t *testing.T) {
+	ss := staticserve.Must(`favicon:scheme {asset}#query?percent%\file.png`, []byte("Hello"))
+
+	jw, err := New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer jw.Close()
+	mux := http.NewServeMux()
+	if err = jw.Setup(mux.Handle, "", ss); err != nil {
+		t.Fatal(err)
+	}
+
+	headURL := jw.FaviconURL()
+	if !strings.HasPrefix(headURL, "/favicon:scheme") {
+		t.Fatalf("favicon URL is not slash-rooted: %q", headURL)
+	}
+	for _, escaped := range []string{"%20", "%7Basset%7D", "%23", "%3F", "%25", "%5C"} {
+		if !strings.Contains(headURL, escaped) {
+			t.Errorf("favicon URL %q does not contain %q", headURL, escaped)
 		}
 	}
+
+	u, err := url.Parse(headURL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if u.RawQuery != "" || u.Fragment != "" {
+		t.Fatalf("favicon URL parsed with query %q and fragment %q", u.RawQuery, u.Fragment)
+	}
+
+	rr := httptest.NewRecorder()
+	mux.ServeHTTP(rr, httptest.NewRequest(http.MethodGet, headURL, nil))
+	if rr.Code != http.StatusOK {
+		t.Fatalf("GET %q = %d, want %d", headURL, rr.Code, http.StatusOK)
+	}
+
+	wildcardURL := strings.Replace(headURL, "%7Basset%7D", "other", 1)
+	rr = httptest.NewRecorder()
+	mux.ServeHTTP(rr, httptest.NewRequest(http.MethodGet, wildcardURL, nil))
+	if rr.Code != http.StatusNotFound {
+		t.Fatalf("GET wildcard candidate %q = %d, want %d", wildcardURL, rr.Code, http.StatusNotFound)
+	}
+}
+
+func TestJaws_SetupEmptyPrefixKeepsGenericRelativeURLs(t *testing.T) {
+	urlExtra, err := url.Parse("url.css")
+	if err != nil {
+		t.Fatal(err)
+	}
+	setupURL, err := url.Parse("setup.css")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tests := []struct {
+		name  string
+		extra any
+		want  string
+	}{
+		{name: "string", extra: "string.css", want: "string.css"},
+		{name: "URL", extra: urlExtra, want: "url.css"},
+		{name: "SetupFunc", extra: SetupFunc(func(_ *Jaws, _ HandleFunc, _ string) (urls []*url.URL, err error) {
+			urls = append(urls, setupURL)
+			return
+		}), want: "setup.css"},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			jw, err := New()
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer jw.Close()
+			if err = jw.Setup(nil, "", tc.extra); err != nil {
+				t.Fatal(err)
+			}
+
+			if !strings.Contains(jw.headPrefix, `href="`+tc.want+`"`) {
+				t.Fatalf("head HTML %q does not contain relative URL %q", jw.headPrefix, tc.want)
+			}
+			if strings.Contains(jw.headPrefix, `href="/`+tc.want+`"`) {
+				t.Fatalf("head HTML %q slash-rooted relative URL %q", jw.headPrefix, tc.want)
+			}
+		})
+	}
 }
 
 func TestJaws_SetupKeepsMethodPattern(t *testing.T) {