util/router/compile.go

@@ -8,18 +8,18 @@ const (
 
 // Template is a compiled representation of path templates.
 type Template struct {
-	// Verb is a VERB part in the template
+	// Version is the version number of the format.
-	Verb string
+	Version int
-	// Original template (example: /v1/a_bit_of_everything)
+	// OpCodes is a sequence of operations.
-	Template string
-	// OpCodes is a sequence of operations
 	OpCodes []int
 	// Pool is a constant pool
 	Pool []string
-	// Fields is a list of field paths bound in this template
+	// Verb is a VERB part in the template.
+	Verb string
+	// Fields is a list of field paths bound in this template.
 	Fields []string
-	// Version is the version number of the format
+	// Original template (example: /v1/a_bit_of_everything)
-	Version int
+	Template string
 }
 
 // Compiler compiles utilities representation of path templates into marshallable operations.
@@ -29,9 +29,15 @@ type Compiler interface {
 }
 
 type op struct {
-	str     string
+	// code is the opcode of the operation
-	code    OpCode
+	code utilities.OpCode
-	operand int
+
+	// str is a string operand of the code.
+	// num is ignored if str is not empty.
+	str string
+
+	// num is a numeric operand of the code.
+	num int
 }
 
 func (w wildcard) compile() []op {
@@ -77,7 +83,6 @@ func (t template) Compile() Template {
 		rawOps = append(rawOps, s.compile()...)
 	}
 
-	// ops := make([]int, 0, len(rawOps))
 	var (
 		ops    []int
 		pool   []string
@@ -87,8 +92,12 @@ func (t template) Compile() Template {
 	for _, op := range rawOps {
 		ops = append(ops, int(op.code))
 		if op.str == "" {
-			ops = append(ops, op.operand)
+			ops = append(ops, op.num)
 		} else {
+			// eof segment literal represents the "/" path pattern
+			if op.str == eof {
+				op.str = ""
+			}
 			if _, ok := consts[op.str]; !ok {
 				consts[op.str] = len(pool)
 				pool = append(pool, op.str)

util/router/compile_test.go

@@ -21,6 +21,13 @@ func TestCompile(t *testing.T) {
 		fields []string
 	}{
 		{},
+		{
+			segs: []segment{
+				literal(eof),
+			},
+			ops:  []int{int(utilities.OpLitPush), 0},
+			pool: []string{""},
+		},
 		{
 			segs: []segment{
 				wildcard{},

util/router/parse.go

@@ -83,8 +83,30 @@ func tokenize(path string) (tokens []string, verb string) {
 	}
 
 	l := len(tokens)
+	// See
+	// https://github.com/grpc-ecosystem/grpc-gateway/pull/1947#issuecomment-774523693 ;
+	// although normal and backwards-compat logic here is to use the last index
+	// of a colon, if the final segment is a variable followed by a colon, the
+	// part following the colon must be a verb. Hence if the previous token is
+	// an end var marker, we switch the index we're looking for to Index instead
+	// of LastIndex, so that we correctly grab the remaining part of the path as
+	// the verb.
+	var penultimateTokenIsEndVar bool
+	switch l {
+	case 0, 1:
+		// Not enough to be variable so skip this logic and don't result in an
+		// invalid index
+	default:
+		penultimateTokenIsEndVar = tokens[l-2] == "}"
+	}
 	t := tokens[l-1]
-	if idx := strings.LastIndex(t, ":"); idx == 0 {
+	var idx int
+	if penultimateTokenIsEndVar {
+		idx = strings.Index(t, ":")
+	} else {
+		idx = strings.LastIndex(t, ":")
+	}
+	if idx == 0 {
 		tokens, verb = tokens[:l-1], t[1:]
 	} else if idx > 0 {
 		tokens[l-1], verb = t[:idx], t[idx+1:]
@@ -101,22 +123,17 @@ type parser struct {
 
 // topLevelSegments is the target of this parser.
 func (p *parser) topLevelSegments() ([]segment, error) {
-	if logger.V(logger.TraceLevel) {
+	if _, err := p.accept(typeEOF); err == nil {
-		logger.Trace(context.TODO(), "Parsing %q", p.tokens)
+		p.tokens = p.tokens[:0]
+		return []segment{literal(eof)}, nil
 	}
 	segs, err := p.segments()
 	if err != nil {
 		return nil, err
 	}
-	if logger.V(logger.TraceLevel) {
-		logger.Trace(context.TODO(), "accept segments: %q; %q", p.accepted, p.tokens)
-	}
 	if _, err := p.accept(typeEOF); err != nil {
 		return nil, fmt.Errorf("unexpected token %q after segments %q", p.tokens[0], strings.Join(p.accepted, ""))
 	}
-	if logger.V(logger.TraceLevel) {
-		logger.Trace(context.TODO(), "accept eof: %q; %q", p.accepted, p.tokens)
-	}
 	return segs, nil
 }
 
@@ -126,9 +143,6 @@ func (p *parser) segments() ([]segment, error) {
 		return nil, err
 	}
 
-	if logger.V(logger.TraceLevel) {
-		logger.Trace(context.TODO(), "accept segment: %q; %q", p.accepted, p.tokens)
-	}
 	segs := []segment{s}
 	for {
 		if _, err := p.accept("/"); err != nil {
@@ -139,9 +153,6 @@ func (p *parser) segments() ([]segment, error) {
 			return segs, err
 		}
 		segs = append(segs, s)
-		if logger.V(logger.TraceLevel) {
-			logger.Trace(context.TODO(), "accept segment: %q; %q", p.accepted, p.tokens)
-		}
 	}
 }
 

util/router/parse_test.go

@@ -16,6 +16,7 @@ func TestTokenize(t *testing.T) {
 	for _, spec := range []struct {
 		src    string
 		tokens []string
+		verb   string
 	}{
 		{
 			src:    "",
@@ -84,6 +85,26 @@ func TestTokenize(t *testing.T) {
 				eof,
 			},
 		},
+		{
+			src: "v1/a/{endpoint}:a",
+			tokens: []string{
+				"v1", "/",
+				"a", "/",
+				"{", "endpoint", "}",
+				eof,
+			},
+			verb: "a",
+		},
+		{
+			src: "v1/a/{endpoint}:b:c",
+			tokens: []string{
+				"v1", "/",
+				"a", "/",
+				"{", "endpoint", "}",
+				eof,
+			},
+			verb: "b:c",
+		},
 	} {
 		tokens, verb := tokenize(spec.src)
 		if got, want := tokens, spec.tokens; !reflect.DeepEqual(got, want) {
@@ -93,23 +114,52 @@ func TestTokenize(t *testing.T) {
 			t.Errorf("tokenize(%q) = _, %q; want _, %q", spec.src, got, want)
 		}
 
-		src := fmt.Sprintf("%s:%s", spec.src, "LOCK")
+		switch {
-		tokens, verb = tokenize(src)
+		case spec.verb != "":
-		if got, want := tokens, spec.tokens; !reflect.DeepEqual(got, want) {
+			if got, want := verb, spec.verb; !reflect.DeepEqual(got, want) {
-			t.Errorf("tokenize(%q) = %q, _; want %q, _", src, got, want)
+				t.Errorf("tokenize(%q) = %q, _; want %q, _", spec.src, got, want)
-		}
+			}
-		if got, want := verb, "LOCK"; got != want {
+
-			t.Errorf("tokenize(%q) = _, %q; want _, %q", src, got, want)
+		default:
+			if got, want := verb, ""; got != want {
+				t.Errorf("tokenize(%q) = _, %q; want _, %q", spec.src, got, want)
+			}
+
+			src := fmt.Sprintf("%s:%s", spec.src, "LOCK")
+			tokens, verb = tokenize(src)
+			if got, want := tokens, spec.tokens; !reflect.DeepEqual(got, want) {
+				t.Errorf("tokenize(%q) = %q, _; want %q, _", src, got, want)
+			}
+			if got, want := verb, "LOCK"; got != want {
+				t.Errorf("tokenize(%q) = _, %q; want _, %q", src, got, want)
+			}
 		}
 	}
 }
 
 func TestParseSegments(t *testing.T) {
-	flag.Set("v", "3")
+	err := flag.Set("v", "3")
+	if err != nil {
+		t.Fatalf("failed to set flag: %v", err)
+	}
 	for _, spec := range []struct {
 		tokens []string
 		want   []segment
 	}{
+		{
+			tokens: []string{eof},
+			want: []segment{
+				literal(eof),
+			},
+		},
+		{
+			// Note: this case will never arise as tokenize() will never return such a sequence of tokens
+			// and even if it does it will be treated as [eof]
+			tokens: []string{eof, "v1", eof},
+			want: []segment{
+				literal(eof),
+			},
+		},
 		{
 			tokens: []string{"v1", eof},
 			want: []segment{
@@ -251,7 +301,10 @@ func TestParseSegments(t *testing.T) {
 }
 
 func TestParseSegmentsWithErrors(t *testing.T) {
-	flag.Set("v", "3")
+	err := flag.Set("v", "3")
+	if err != nil {
+		t.Fatalf("failed to set flag: %v", err)
+	}
 	for _, spec := range []struct {
 		tokens []string
 	}{
@@ -275,10 +328,6 @@ func TestParseSegmentsWithErrors(t *testing.T) {
 			// invalid percent-encoding
 			tokens: []string{"a%2z", eof},
 		},
-		{
-			// empty segments
-			tokens: []string{eof},
-		},
 		{
 			// unterminated variable
 			tokens: []string{"{", "name", eof},

util/router/runtime.go

@@ -23,9 +23,9 @@ type rop struct {
 	operand int
 }
 
-// Pattern is a template pattern of http request paths defined in github.com/googleapis/googleapis/google/api/http.proto.
+// Pattern is a template pattern of http request paths defined in
+// https://github.com/googleapis/googleapis/blob/master/google/api/http.proto
 type Pattern struct {
-	verb string
 	// ops is a list of operations
 	ops []rop
 	// pool is a constant pool indexed by the operands or vars
@@ -36,32 +36,16 @@ type Pattern struct {
 	stacksize int
 	// tailLen is the length of the fixed-size segments after a deep wildcard
 	tailLen int
-	// assumeColonVerb indicates whether a path suffix after a final
+	// verb is the VERB part of the path pattern. It is empty if the pattern does not have VERB part.
-	// colon may only be interpreted as a verb.
+	verb string
-	assumeColonVerb bool
 }
 
-type patternOptions struct {
-	assumeColonVerb bool
-}
-
-// PatternOpt is an option for creating Patterns.
-type PatternOpt func(*patternOptions)
-
 // NewPattern returns a new Pattern from the given definition values.
 // "ops" is a sequence of op codes. "pool" is a constant pool.
 // "verb" is the verb part of the pattern. It is empty if the pattern does not have the part.
 // "version" must be 1 for now.
 // It returns an error if the given definition is invalid.
-//nolint:gocyclo
+func NewPattern(version int, ops []int, pool []string, verb string) (Pattern, error) {
-func NewPattern(version int, ops []int, pool []string, verb string, opts ...PatternOpt) (Pattern, error) {
-	options := patternOptions{
-		assumeColonVerb: true,
-	}
-	for _, o := range opts {
-		o(&options)
-	}
-
 	if version != 1 {
 		if logger.V(logger.TraceLevel) {
 			logger.Trace(context.TODO(), "unsupported version: %d", version)
@@ -185,7 +169,7 @@ func MustPattern(p Pattern, err error) Pattern {
 //nolint:gocyclo
 func (p Pattern) Match(components []string, verb string) (map[string]string, error) {
 	if p.verb != verb {
-		if p.assumeColonVerb || p.verb != "" {
+		if p.verb != "" {
 			return nil, ErrNotMatch
 		}
 		if len(components) == 0 {
@@ -274,11 +258,3 @@ func (p Pattern) String() string {
 	}
 	return "/" + segs
 }
-
-// AssumeColonVerbOpt indicates whether a path suffix after a final
-// colon may only be interpreted as a verb.
-func AssumeColonVerbOpt(val bool) PatternOpt {
-	return PatternOpt(func(o *patternOptions) {
-		o.assumeColonVerb = val
-	})
-}

util/router/types.go

@@ -8,9 +8,9 @@ import (
 )
 
 type template struct {
+	segments []segment
 	verb     string
 	template string
-	segments []segment
 }
 
 type segment interface {