PLT-1465 Added password requirements (#3489)

* Added password requirements

* added tweaks

* fixed error code

* removed http.StatusNotAcceptable

utils/password.go

@@ -0,0 +1,64 @@
+// Copyright (c) 2016 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package utils
+
+import (
+	"github.com/mattermost/platform/model"
+	"strings"
+)
+
+func IsPasswordValid(password string) *model.AppError {
+	id := "model.user.is_valid.pwd"
+	isError := false
+	min := model.PASSWORD_MINIMUM_LENGTH
+
+	if IsLicensed && *License.Features.PasswordRequirements {
+		if len(password) < *Cfg.PasswordSettings.MinimumLength || len(password) > model.PASSWORD_MAXIMUM_LENGTH {
+			isError = true
+		}
+
+		if *Cfg.PasswordSettings.Lowercase {
+			if !strings.ContainsAny(password, model.LOWERCASE_LETTERS) {
+				isError = true
+			}
+
+			id = id + "_lowercase"
+		}
+
+		if *Cfg.PasswordSettings.Uppercase {
+			if !strings.ContainsAny(password, model.UPPERCASE_LETTERS) {
+				isError = true
+			}
+
+			id = id + "_uppercase"
+		}
+
+		if *Cfg.PasswordSettings.Number {
+			if !strings.ContainsAny(password, model.NUMBERS) {
+				isError = true
+			}
+
+			id = id + "_number"
+		}
+
+		if *Cfg.PasswordSettings.Symbol {
+			if !strings.ContainsAny(password, model.SYMBOLS) {
+				isError = true
+			}
+
+			id = id + "_symbol"
+		}
+
+		min = *Cfg.PasswordSettings.MinimumLength
+	} else if len(password) > model.PASSWORD_MAXIMUM_LENGTH || len(password) < model.PASSWORD_MINIMUM_LENGTH {
+		isError = true
+		min = model.PASSWORD_MINIMUM_LENGTH
+	}
+
+	if isError {
+		return model.NewLocAppError("User.IsValid", id+".app_error", map[string]interface{}{"Min": min}, "")
+	}
+
+	return nil
+}