proxy: add route portal json (#5428)

* proxy: add route portal json

* fix 405 issue

* add link to issue

* Update proxy/portal/filter_test.go

Co-authored-by: Kenneth Jenkins <51246568+kenjenkins@users.noreply.github.com>

---------

Co-authored-by: Kenneth Jenkins <51246568+kenjenkins@users.noreply.github.com>

proxy/portal/matchers.go

@@ -0,0 +1,108 @@
+package portal
+
+import (
+	"strings"
+
+	"github.com/pomerium/pomerium/pkg/policy/parser"
+)
+
+type matcher[T any] func(left T, right parser.Value) bool
+
+var stringMatchers = map[string]matcher[string]{
+	"contains":    matchStringContains,
+	"ends_with":   matchStringEndsWith,
+	"is":          matchStringIs,
+	"starts_with": matchStringStartsWith,
+}
+
+var stringListMatchers = map[string]matcher[[]string]{
+	"has": matchStringListHas,
+	"is":  matchStringListIs,
+}
+
+func matchString(left string, right parser.Value) bool {
+	obj, ok := right.(parser.Object)
+	if !ok {
+		obj = parser.Object{
+			"is": right,
+		}
+	}
+
+	for k, v := range obj {
+		f, ok := stringMatchers[k]
+		if !ok {
+			return false
+		}
+		ok = f(left, v)
+		if ok {
+			return true
+		}
+	}
+	return false
+}
+
+func matchStringContains(left string, right parser.Value) bool {
+	str, ok := right.(parser.String)
+	if !ok {
+		return false
+	}
+	return strings.Contains(left, string(str))
+}
+
+func matchStringEndsWith(left string, right parser.Value) bool {
+	str, ok := right.(parser.String)
+	if !ok {
+		return false
+	}
+	return strings.HasSuffix(left, string(str))
+}
+
+func matchStringIs(left string, right parser.Value) bool {
+	str, ok := right.(parser.String)
+	if !ok {
+		return false
+	}
+	return left == string(str)
+}
+
+func matchStringStartsWith(left string, right parser.Value) bool {
+	str, ok := right.(parser.String)
+	if !ok {
+		return false
+	}
+	return strings.HasPrefix(left, string(str))
+}
+
+func matchStringList(left []string, right parser.Value) bool {
+	obj, ok := right.(parser.Object)
+	if !ok {
+		obj = parser.Object{
+			"has": right,
+		}
+	}
+
+	for k, v := range obj {
+		f, ok := stringListMatchers[k]
+		if !ok {
+			return false
+		}
+		ok = f(left, v)
+		if ok {
+			return true
+		}
+	}
+	return false
+}
+
+func matchStringListHas(left []string, right parser.Value) bool {
+	for _, str := range left {
+		if matchStringIs(str, right) {
+			return true
+		}
+	}
+	return false
+}
+
+func matchStringListIs(left []string, right parser.Value) bool {
+	return len(left) == 1 && matchStringListHas(left, right)
+}