If a pattern has no verb, match with a verb arg appended to last comp…

…onent

Parsing out a "verb" from the input path is a convenience for
parsing. Whether the colon and string are _actually_ a verb depends on
the matching HTTP rule. This change gives a verb-less pattern a chance
to match a path by assuming the colon+string suffix are a part of the
final component.

Fixes grpc-ecosystem#224

Signed-off-by: James Hamlin <james@goforward.com>

runtime/mux.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"context"
+
 	"github.com/golang/protobuf/proto"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/metadata"

runtime/pattern.go

@@ -144,7 +144,16 @@ func MustPattern(p Pattern, err error) Pattern {
 // If otherwise, the function returns an error.
 func (p Pattern) Match(components []string, verb string) (map[string]string, error) {
 	if p.verb != verb {
-		return nil, ErrNotMatch
+		if p.verb != "" {
+			return nil, ErrNotMatch
+		}
+		if len(components) == 0 {
+			components = []string{":" + verb}
+		} else {
+			components = append([]string{}, components...)
+			components[len(components)-1] += ":" + verb
+		}
+		verb = ""
 	}
 
 	var pos int