username check returns more apropriate error message

Fix broken links to mxisd docs

README.md

@@ -1,4 +1,6 @@
 # matrix-register-bot
+![state: alpha](https://img.shields.io/badge/state-alpha-yellowgreen.svg)
+[![#matrix-register-bot:msg-net.de](https://img.shields.io/badge/matrix-%23matrix--register--bot%3Amsg--net.de-brightgreen.svg)](https://matrix.to/#/#matrix-register-bot:msg-net.de)
 
 This bot provides a two-step-registration for matrix ([synapse](https://github.com/matrix-org/synapse)).
 
@@ -16,7 +18,7 @@ To configure synapse so that the users can login that were created via this bot
 - set `operationMode=synapse` so the bot uses the register api to push the new users to synapse or 
 - integrate it via [matrix-synapse-rest-auth](https://github.com/kamax-io/matrix-synapse-rest-auth#integrate) by configuring your system to point at `internal/login.php`.
 
-When using `operationMode=local` you can have the following benefits (some require [mxisd](https://github.com/kamax-io/mxisd/blob/master/docs/backends/rest.md))
+When using `operationMode=local` you can have the following benefits (some require [mxisd](https://github.com/kamax-io/mxisd/blob/master/docs/stores/rest.md))
 - Automatically set the display name based on first and last name on first login
 - Use the 3PID lookup for other users (only email)
 - Search for users that you have not seen yet
@@ -28,7 +30,7 @@ When using `operationMode=local` you can have the following benefits (some requi
   The folder `internal` contains files that only provide API access. They can be accessed by mxisd or matrix-synapse-rest-auth 
 - To integrate with [matrix-synapse-rest-auth](https://github.com/kamax-io/matrix-synapse-rest-auth):
   - `/_matrix-internal/identity/v1/check_credentials` should map to `internal/login.php`
-- To integrate with [mxisd](https://github.com/kamax-io/mxisd): Have a look at [the docs of mxisd](https://github.com/kamax-io/mxisd/blob/master/docs/backends/rest.md) and apply as follows:
+- To integrate with [mxisd](https://github.com/kamax-io/mxisd): Have a look at [the docs of mxisd](https://github.com/kamax-io/mxisd/blob/master/docs/stores/rest.md) and apply as follows:
 
 
 | Key                            | file which handles that       | Description                                          |
@@ -58,6 +60,3 @@ Here is an example for nginx:
 ### The bot postpones some actions
 There is a cron.php which implements retries and database cleanups (e.g. to remove a username claim)
 For this run cron.php regularly with your system of choice.
-
-### Chat
-For further questions, comments, feedback and more come and talk in [#matrix-register-bot:msg-net.de](https://matrix.to/#/#matrix-register-bot:msg-net.de)

lang/lang.de-de.php

@@ -31,7 +31,7 @@ $language = array(
     "UNKNOWN_SESSION" => "Sitzungstoken nicht vorhanden oder ungültig.",
     "UNKNOWN_USERNAME" => "Nutzername fehlt",
     "UNKNOWN_TOKEN" => "Token ist unbekannt",
-    "USERNAME_LENGTH_INVALID" => "Entweder mehr als 20 oder weniger als 3 Zeichen für den Nutzernamen verwendet",
+    "USERNAME_INVALID" => "Nutzername muss aus 3 bis 20 Kleinbuchstaben bestehen",
     "USERNAME_NOT_ALNUM" => "Nutzername ist nicht alphanumerisch",
     "USERNAME_PENDING_REGISTRATION" => "Dieser Nutzername wurde bereits zur Registrierung vorgemerkt. Versuche es später noch einmal oder wähle einen anderen Nutzernamen",
     "USERNAME_REGISTERED" => "Dieser Nutzername wurde bereits registriert. Bitte wähle einen anderen Nutzernamen",

lang/lang.en-gb.php

@@ -31,7 +31,7 @@ $language = array(
     "UNKNOWN_SESSION" => "Session token not found of invalid.",
     "UNKNOWN_USERNAME" => "username unknown",
     "UNKNOWN_TOKEN" => "Token is unknown",
-    "USERNAME_LENGTH_INVALID" => "Username cpnsists pf more than 20 or less than 3 characters",
+    "USERNAME_INVALID" => "Username has to consist of 3 to 20 small letters",
     "USERNAME_NOT_ALNUM" => "Username is not alphanumeric",
     "USERNAME_PENDING_REGISTRATION" => "This username is locked for registration. Try again later or try again with a different username",
     "USERNAME_REGISTERED" => "This username is already registered. Please try again with another username",

public/index.php

@@ -49,8 +49,10 @@ if ($_SERVER["REQUEST_METHOD"] == "POST") {
         if (!isset($_POST["username"])) {
             throw new Exception("UNKNOWN_USERNAME");
         }
-        if (strlen($_POST["username"] > 20 || strlen($_POST["username"]) < 3)) {
-            throw new Exception("USERNAME_LENGTH_INVALID");
+        if (strlen($_POST["username"]) > 20 ||
+                strlen($_POST["username"]) < 3 ||
+                !ctype_lower($_POST["username"])) {
+            throw new Exception("USERNAME_INVALID");
         }
         if (ctype_alnum($_POST['username']) != true) {
             throw new Exception("USERNAME_NOT_ALNUM");
@@ -215,7 +217,7 @@ if ($_SERVER["REQUEST_METHOD"] == "POST") {
     <script type="text/javascript">
         var user_name = document.getElementById("username");
         user_name.oninvalid = function (event) {
-            event.target.setCustomValidity("<?php echo $language["USERNAME_LENGTH_INVALID"]; ?>");
+            event.target.setCustomValidity("<?php echo $language["USERNAME_INVALID"]; ?>");
         }
         user_name.onkeyup = function (event) {
             event.target.setCustomValidity("");