#66405 add Pattern and SetPattern in Request

Author: sillydong

src/net/http/request.go

@@ -1561,3 +1561,36 @@ func (r *Request) requiresHTTP1() bool {
 	return hasToken(r.Header.Get("Connection"), "upgrade") &&
 		ascii.EqualFold(r.Header.Get("Upgrade"), "websocket")
 }
+
+// SetPattern parses a string into a Pattern and set in Request.
+// The string's syntax is
+//
+//	[METHOD] [HOST]/[PATH]
+//
+// where:
+//   - METHOD is an HTTP method
+//   - HOST is a hostname
+//   - PATH consists of slash-separated segments, where each segment is either
+//     a literal or a wildcard of the form "{name}", "{name...}", or "{$}".
+//
+// METHOD, HOST and PATH are all optional; that is, the string can be "/".
+// If METHOD is present, it must be followed by at least one space or tab.
+// Wildcard names must be valid Go identifiers.
+// The "{$}" and "{name...}" wildcard must occur at the end of PATH.
+// PATH may end with a '/'.
+// Wildcard names in a path must be distinct.
+func (r *Request) SetPattern(s string) error {
+	pat, err := parsePattern(s)
+	if err != nil {
+		return err
+	}
+	r.pat = pat
+	return nil
+}
+
+// Pattern returns the pattern that matched this request, if the request
+// resulted from matching a pattern registered on a ServeMux.
+// Otherwise, it returns the empty string.
+func (r *Request) Pattern() string {
+	return r.pat.str
+}

src/net/http/request_test.go

@@ -1527,7 +1527,7 @@ func TestPathValueNoMatch(t *testing.T) {
 	}
 }
 
-func TestPathValue(t *testing.T) {
+func TestPathValueAndPattern(t *testing.T) {
 	for _, test := range []struct {
 		pattern string
 		url     string
@@ -1568,6 +1568,9 @@ func TestPathValue(t *testing.T) {
 					t.Errorf("%q, %q: got %q, want %q", test.pattern, name, got, want)
 				}
 			}
+			if r.Pattern() != test.pattern {
+				t.Errorf("pattern: got %s, want %s", r.Pattern(), test.pattern)
+			}
 		})
 		server := httptest.NewServer(mux)
 		defer server.Close()
@@ -1652,3 +1655,25 @@ func TestStatus(t *testing.T) {
 		}
 	}
 }
+
+func TestSetPattern(t *testing.T) {
+	patterns := []string{
+		"GET /",
+		"HEAD /test",
+		"/",
+		"/foo/bar",
+		"GET /foo/{b...}",
+		"GET /{f}",
+	}
+
+	req := new(Request)
+	for _, pattern := range patterns {
+		err := req.SetPattern(pattern)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if req.Pattern() != pattern {
+			t.Errorf("pattern doesn't match, got %s, want %s", req.Pattern(), pattern)
+		}
+	}
+}