Added match() regex matching to expr

pkg/apigw/filter/prefilter_test.go

@@ -43,6 +43,11 @@ func Test_header(t *testing.T) {
 				headers: map[string][]string{"Foo": {"bar"}},
 				err:     "could not validate headers: failed to select 'Foo1' on *expr.Vars: no such key 'Foo1'",
 			},
+			{
+				name:    "regex matching key",
+				expr:    `{"expr":"match(Foo, \"^b\\\\wr\\\\s.*$\")"}`,
+				headers: map[string][]string{"Foo": {"bar "}},
+			},
 			// {
 			// 	name:    "matching header with hyphen - TODO",
 			// 	expr:    `{"expr":"Content-type == \"application/json\""}`,

pkg/expr/func_str.go

@@ -3,11 +3,12 @@ package expr
 import (
 	"errors"
 	"fmt"
-	"github.com/spf13/cast"
 	"reflect"
 	"regexp"
 	"strings"
 
+	"github.com/spf13/cast"
+
 	"github.com/PaesslerAG/gval"
 	valid "github.com/asaskevich/govalidator"
 )
@@ -37,6 +38,7 @@ func StringFunctions() []gval.Language {
 		gvalFunc("shorten", shorten),
 		gval.Function("camelize", camelize),
 		gval.Function("snakify", snakify),
+		gval.Function("match", match),
 	}
 }
 
@@ -198,3 +200,21 @@ func camelize(s string) string {
 func snakify(s string) string {
 	return strings.ToLower(strings.Replace(strings.Title(s), " ", "_", -1))
 }
+
+func match(s string, regex interface{}) (b bool, err error) {
+	var (
+		r *regexp.Regexp
+	)
+
+	switch v := regex.(type) {
+	case *regexp.Regexp:
+		r = v
+	case string:
+		if r, err = regexp.Compile(v); err != nil {
+			return
+		}
+	}
+
+	b = r.MatchString(s)
+	return
+}

pkg/expr/func_str_test.go

@@ -189,3 +189,10 @@ func Example_substring_endOverflow() {
 	// output:
 	// o bar baz_test
 }
+
+func Example_match() {
+	eval(`match("foo bar baz_test", "^foo\\s.*$")`, nil)
+
+	// output:
+	// true
+}