Util tweaks

- Move rand util into rand.go
- RandString changed to RandomID and uses 256 bits
- Move string util into strings.go

util/file.go

@@ -114,7 +114,7 @@ func RemoveFileAtPath(path string) {
 //   openTempFile(path.Join(os.TempDir(), "foo"), "", 0600) => "/tmp/foo.RCG2KUSCGYOO3PCKNWQHBOXBKACOPIKL"
 //
 func openTempFile(prefix string, suffix string, mode os.FileMode) (string, *os.File, error) {
-	filename, err := RandString(prefix, 20)
+	filename, err := RandomID(prefix)
 	if err != nil {
 		return "", nil, err
 	}
@@ -171,7 +171,7 @@ func TempPath(tempDir string, prefix string) string {
 	if tempDir == "" {
 		tempDir = os.TempDir()
 	}
-	filename, err := RandString(prefix, 20)
+	filename, err := RandomID(prefix)
 	if err != nil {
 		// We had an error getting random bytes, we'll use current nanoseconds
 		filename = fmt.Sprintf("%s%d", prefix, time.Now().UnixNano())

util/file_test.go

@@ -62,7 +62,7 @@ func TestTempPathValid(t *testing.T) {
 	tempPath := TempPath("", "TempPrefix.")
 	t.Logf("Temp path: %s", tempPath)
 	assert.True(t, strings.HasPrefix(filepath.Base(tempPath), "TempPrefix."))
-	assert.Equal(t, len(filepath.Base(tempPath)), 43)
+	assert.Equal(t, len(filepath.Base(tempPath)), 63)
 }
 
 func TestTempPathRandFail(t *testing.T) {

util/util.go → util/rand.go

@@ -9,29 +9,20 @@ import (
 	"strings"
 )
 
-// JoinPredicate joins strings with predicate
-func JoinPredicate(arr []string, delimeter string, f func(s string) bool) string {
-	arrNew := make([]string, 0, len(arr))
-	for _, s := range arr {
-		if f(s) {
-			arrNew = append(arrNew, s)
-		}
-	}
-	return strings.Join(arrNew, delimeter)
-}
+var randRead = rand.Read
 
-// RandString returns random (base32) string with prefix.
-func RandString(prefix string, numbytes int) (string, error) {
-	buf, err := RandBytes(numbytes)
+// RandomID returns random ID (base32) string with prefix, using 256 bits as
+// recommended by tptacek: https://gist.github.com/tqbf/be58d2d39690c3b366ad
+func RandomID(prefix string) (string, error) {
+	buf, err := RandBytes(32)
 	if err != nil {
 		return "", err
 	}
 	str := prefix + base32.StdEncoding.EncodeToString(buf)
+	str = strings.Replace(str, "=", "", -1)
 	return str, nil
 }
 
-var randRead = rand.Read
-
 // RandBytes returns random bytes of length
 func RandBytes(length int) ([]byte, error) {
 	buf := make([]byte, length)

util/rand_test.go

@@ -0,0 +1,23 @@
+// Copyright 2015 Keybase, Inc. All rights reserved. Use of
+// this source code is governed by the included BSD license.
+
+package util
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestRandString(t *testing.T) {
+	s, err := RandomID("prefix.")
+	t.Logf("Rand string: %s", s)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.HasPrefix(s, "prefix.") {
+		t.Errorf("Invalid prefix: %s", s)
+	}
+	if len(s)-len("prefix.") != 52 {
+		t.Errorf("Invalid length: %s (%d)", s, len(s))
+	}
+}

util/strings.go

@@ -0,0 +1,17 @@
+// Copyright 2015 Keybase, Inc. All rights reserved. Use of
+// this source code is governed by the included BSD license.
+
+package util
+
+import "strings"
+
+// JoinPredicate joins strings with predicate
+func JoinPredicate(arr []string, delimeter string, f func(s string) bool) string {
+	arrNew := make([]string, 0, len(arr))
+	for _, s := range arr {
+		if f(s) {
+			arrNew = append(arrNew, s)
+		}
+	}
+	return strings.Join(arrNew, delimeter)
+}

util/strings_test.go

@@ -0,0 +1,17 @@
+// Copyright 2015 Keybase, Inc. All rights reserved. Use of
+// this source code is governed by the included BSD license.
+
+package util
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestJoinPredicate(t *testing.T) {
+	f := func(s string) bool { return strings.HasPrefix(s, "f") }
+	s := JoinPredicate([]string{"foo", "bar", "faa"}, "-", f)
+	if s != "foo-faa" {
+		t.Errorf("Unexpected output: %s", s)
+	}
+}

util/util_test.go

@@ -3,33 +3,6 @@
 
 package util
 
-import (
-	"strings"
-	"testing"
-
-	"github.com/keybase/go-logging"
-)
+import "github.com/keybase/go-logging"
 
 var testLog = logging.Logger{Module: "test"}
-
-func TestJoinPredicate(t *testing.T) {
-	f := func(s string) bool { return strings.HasPrefix(s, "f") }
-	s := JoinPredicate([]string{"foo", "bar", "faa"}, "-", f)
-	if s != "foo-faa" {
-		t.Errorf("Unexpected output: %s", s)
-	}
-}
-
-func TestRandString(t *testing.T) {
-	s, err := RandString("prefix", 20)
-	t.Logf("Rand string: %s", s)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if !strings.HasPrefix(s, "prefix") {
-		t.Errorf("Invalid prefix: %s", s)
-	}
-	if len(s) != 38 {
-		t.Errorf("Invalid length: %s (%d)", s, len(s))
-	}
-}