From 01c824bbfa322beeb99b1260235b7656b1e11fa0 Mon Sep 17 00:00:00 2001
From: Vasiliy Tolstov <v.tolstov@unistack.org>
Date: Wed, 29 Apr 2020 15:23:10 +0300
Subject: [PATCH] api/router: avoid unneeded loops and fix path match (#1594)

* api/router: avoid unneeded loops and fix path match

* if match found in google api path syntax, not try pcre loop
* if path is not ending via $ sign, append it to pcre to avoid matching other strings like
  /api/account/register can be matched to /api/account
* api: add tests and validations

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>
---
 static.go | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/static.go b/static.go
index 367a53d..7bcf1d7 100644
--- a/static.go
+++ b/static.go
@@ -110,10 +110,14 @@ func (r *staticRouter) Register(ep *api.Endpoint) error {
 
 	for _, p := range ep.Path {
 		var pcreok bool
-		pcrereg, err := regexp.CompilePOSIX(p)
-		if err == nil {
-			pcreregs = append(pcreregs, pcrereg)
-			pcreok = true
+
+		// pcre only when we have start and end markers
+		if p[0] == '^' && p[len(p)-1] == '$' {
+			pcrereg, err := regexp.CompilePOSIX(p)
+			if err == nil {
+				pcreregs = append(pcreregs, pcrereg)
+				pcreok = true
+			}
 		}
 
 		rule, err := util.Parse(p)
@@ -122,6 +126,7 @@ func (r *staticRouter) Register(ep *api.Endpoint) error {
 		} else if err != nil && pcreok {
 			continue
 		}
+
 		tpl := rule.Compile()
 		pathreg, err := util.NewPattern(tpl.Version, tpl.OpCodes, tpl.Pool, "")
 		if err != nil {
@@ -280,6 +285,9 @@ func (r *staticRouter) endpoint(req *http.Request) (*endpoint, error) {
 				}
 				continue
 			}
+			if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+				logger.Debugf("api gpath match %s = %v", path, pathreg)
+			}
 			pMatch = true
 			ctx := req.Context()
 			md, ok := metadata.FromContext(ctx)
@@ -294,16 +302,18 @@ func (r *staticRouter) endpoint(req *http.Request) (*endpoint, error) {
 			break
 		}
 
-		// 4. try path via pcre path matching
-		for _, pathreg := range ep.pcreregs {
-			if !pathreg.MatchString(req.URL.Path) {
-				if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-					logger.Debugf("api pcre path not match %s != %v", req.URL.Path, pathreg)
+		if !pMatch {
+			// 4. try path via pcre path matching
+			for _, pathreg := range ep.pcreregs {
+				if !pathreg.MatchString(req.URL.Path) {
+					if logger.V(logger.DebugLevel, logger.DefaultLogger) {
+						logger.Debugf("api pcre path not match %s != %v", req.URL.Path, pathreg)
+					}
+					continue
 				}
-				continue
+				pMatch = true
+				break
 			}
-			pMatch = true
-			break
 		}
 
 		if !pMatch {