From 319c10853c1961621a0c1ae05ac95b20a0ce277e Mon Sep 17 00:00:00 2001
From: Sebastien Douheret <sebastien.douheret@iot.bzh>
Date: Thu, 18 May 2017 10:55:19 +0200
Subject: [PATCH] Fix ResolveEnvVar function and add support of tilde (~/...)

---
 lib/common/filepath.go      | 41 ++++++++++++++++++++++++++++++++++++++++-
 lib/xdsconfig/fileconfig.go | 26 ++++----------------------
 2 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/lib/common/filepath.go b/lib/common/filepath.go
index 603c2a2..42ef82f 100644
--- a/lib/common/filepath.go
+++ b/lib/common/filepath.go
@@ -1,6 +1,13 @@
 package common
 
-import "os"
+import (
+	"fmt"
+	"os"
+	"os/user"
+	"path"
+	"path/filepath"
+	"regexp"
+)
 
 // Exists returns whether the given file or directory exists or not
 func Exists(path string) bool {
@@ -13,3 +20,35 @@ func Exists(path string) bool {
 	}
 	return true
 }
+
+// ResolveEnvVar Resolved environment variable regarding the syntax ${MYVAR}
+// or $MYVAR following by a slash or a backslash
+func ResolveEnvVar(s string) (string, error) {
+
+	// Resolved tilde : ~/
+	if s[:2] == "~/" {
+		if usr, err := user.Current(); err == nil {
+			s = filepath.Join(usr.HomeDir, s[2:])
+		}
+	}
+
+	// Resolved ${MYVAR}
+	re := regexp.MustCompile("\\${([^}]+)}")
+	vars := re.FindAllStringSubmatch(s, -1)
+	res := s
+	for _, v := range vars {
+		val := os.Getenv(v[1])
+		if val == "" {
+			return res, fmt.Errorf("ERROR: %s env variable not defined", v[1])
+		}
+
+		rer := regexp.MustCompile("\\${" + v[1] + "}")
+		res = rer.ReplaceAllString(res, val)
+	}
+
+	// Resolved $MYVAR following by a slash (or a backslash for Windows)
+	// TODO
+	//re := regexp.MustCompile("\\$([^\\/])+/")
+
+	return path.Clean(res), nil
+}
diff --git a/lib/xdsconfig/fileconfig.go b/lib/xdsconfig/fileconfig.go
index 5cf8db2..535ee59 100644
--- a/lib/xdsconfig/fileconfig.go
+++ b/lib/xdsconfig/fileconfig.go
@@ -2,12 +2,12 @@ package xdsconfig
 
 import (
 	"encoding/json"
-	"fmt"
 	"os"
 	"os/user"
 	"path"
 	"path/filepath"
-	"regexp"
+
+	"github.com/iotbzh/xds-agent/lib/common"
 )
 
 type SyncThingConf struct {
@@ -79,11 +79,11 @@ func updateConfigFromFile(c *Config, confFile string) (*FileConfig, error) {
 		&fCfg.SThgConf.Home,
 		&fCfg.SThgConf.BinDir} {
 
-		rep, err := resolveEnvVar(*field)
+		var err error
+		*field, err = common.ResolveEnvVar(*field)
 		if err != nil {
 			return nil, err
 		}
-		*field = path.Clean(rep)
 	}
 
 	// Config file settings overwrite default config
@@ -93,21 +93,3 @@ func updateConfigFromFile(c *Config, confFile string) (*FileConfig, error) {
 
 	return &fCfg, nil
 }
-
-// resolveEnvVar Resolved environment variable regarding the syntax ${MYVAR}
-func resolveEnvVar(s string) (string, error) {
-	re := regexp.MustCompile("\\${(.*)}")
-	vars := re.FindAllStringSubmatch(s, -1)
-	res := s
-	for _, v := range vars {
-		val := os.Getenv(v[1])
-		if val == "" {
-			return res, fmt.Errorf("ERROR: %s env variable not defined", v[1])
-		}
-
-		rer := regexp.MustCompile("\\${" + v[1] + "}")
-		res = rer.ReplaceAllString(res, val)
-	}
-
-	return res, nil
-}
-- 
2.16.6