From 2466ed148466ee17fb4da6d2d732e1a16f0469a6 Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Thu, 16 Jan 2020 11:29:20 -0700
Subject: httpcaddyfile: Group try_files routes together (#2891)

This ensures that only the first matching route is used.
---
 caddyconfig/httpcaddyfile/directives.go   | 36 +++++++++++++++++++++++++++----
 caddyconfig/httpcaddyfile/httptype.go     | 12 ++++++-----
 modules/caddyhttp/fileserver/caddyfile.go |  5 +++++
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/caddyconfig/httpcaddyfile/directives.go b/caddyconfig/httpcaddyfile/directives.go
index 50e27d6..e74a3fe 100644
--- a/caddyconfig/httpcaddyfile/directives.go
+++ b/caddyconfig/httpcaddyfile/directives.go
@@ -16,6 +16,7 @@ package httpcaddyfile
 
 import (
 	"encoding/json"
+	"fmt"
 	"sort"
 
 	"github.com/caddyserver/caddy/v2"
@@ -93,10 +94,11 @@ func RegisterHandlerDirective(dir string, setupFunc UnmarshalHandlerFunc) {
 // Caddyfile tokens.
 type Helper struct {
 	*caddyfile.Dispenser
-	options     map[string]interface{}
-	warnings    *[]caddyconfig.Warning
-	matcherDefs map[string]caddy.ModuleMap
-	parentBlock caddyfile.ServerBlock
+	options      map[string]interface{}
+	warnings     *[]caddyconfig.Warning
+	matcherDefs  map[string]caddy.ModuleMap
+	parentBlock  caddyfile.ServerBlock
+	groupCounter *int
 }
 
 // Option gets the option keyed by name.
@@ -166,6 +168,32 @@ func (h Helper) NewRoute(matcherSet caddy.ModuleMap,
 	}
 }
 
+func (h Helper) GroupRoutes(vals []ConfigValue) {
+	// ensure there's at least two routes; group of one is pointless
+	var count int
+	for _, v := range vals {
+		if _, ok := v.Value.(caddyhttp.Route); ok {
+			count++
+			if count > 1 {
+				break
+			}
+		}
+	}
+	if count < 2 {
+		return
+	}
+
+	// now that we know the group will have some effect, do it
+	groupNum := *h.groupCounter
+	for i := 0; i < len(vals); i++ {
+		if route, ok := vals[i].Value.(caddyhttp.Route); ok {
+			route.Group = fmt.Sprintf("group%d", groupNum)
+			vals[i].Value = route
+		}
+	}
+	*h.groupCounter++
+}
+
 // NewBindAddresses returns config values relevant to adding
 // listener bind addresses to the config.
 func (h Helper) NewBindAddresses(addrs []string) []ConfigValue {
diff --git a/caddyconfig/httpcaddyfile/httptype.go b/caddyconfig/httpcaddyfile/httptype.go
index e2035d7..257e7be 100644
--- a/caddyconfig/httpcaddyfile/httptype.go
+++ b/caddyconfig/httpcaddyfile/httptype.go
@@ -41,6 +41,7 @@ type ServerType struct {
 func (st ServerType) Setup(originalServerBlocks []caddyfile.ServerBlock,
 	options map[string]interface{}) (*caddy.Config, []caddyconfig.Warning, error) {
 	var warnings []caddyconfig.Warning
+	groupCounter := new(int)
 
 	var serverBlocks []serverBlock
 	for _, sblock := range originalServerBlocks {
@@ -140,11 +141,12 @@ func (st ServerType) Setup(originalServerBlocks []caddyfile.ServerBlock,
 			}
 
 			results, err := dirFunc(Helper{
-				Dispenser:   caddyfile.NewDispenser(segment),
-				options:     options,
-				warnings:    &warnings,
-				matcherDefs: matcherDefs,
-				parentBlock: sb.block,
+				Dispenser:    caddyfile.NewDispenser(segment),
+				options:      options,
+				warnings:     &warnings,
+				matcherDefs:  matcherDefs,
+				parentBlock:  sb.block,
+				groupCounter: groupCounter,
 			})
 			if err != nil {
 				return nil, warnings, fmt.Errorf("parsing caddyfile tokens for '%s': %v", dir, err)
diff --git a/modules/caddyhttp/fileserver/caddyfile.go b/modules/caddyhttp/fileserver/caddyfile.go
index d26b435..67ae4f4 100644
--- a/modules/caddyhttp/fileserver/caddyfile.go
+++ b/modules/caddyhttp/fileserver/caddyfile.go
@@ -163,5 +163,10 @@ func parseTryFiles(h httpcaddyfile.Helper) ([]httpcaddyfile.ConfigValue, error)
 		result = append(result, makeRoute(try, "")...)
 	}
 
+	// ensure that multiple routes (possible if rewrite targets
+	// have query strings, for example) are grouped together
+	// so only the first matching rewrite is performed (#2891)
+	h.GroupRoutes(result)
+
 	return result, nil
 }
-- 
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