[4.0] Adding error handling for installer

installation/language/en-GB/en-GB.ini

@@ -65,6 +65,7 @@ INSTL_DATABASE_NO_SCHEMA="No database schema exists for this database type."
 INSTL_DATABASE_PASSWORD_DESC="Either a password you created or a password provided by your host."
 INSTL_DATABASE_PREFIX_DESC="Enter a table prefix or use the randomly generated one."
 INSTL_DATABASE_PREFIX_MSG="The table prefix must start with a letter, optionally be followed by alphanumeric characters and by an underscore"
+INSTL_DATABASE_RESPONSE_ERROR="The latest request returned an invalid response:"
 INSTL_DATABASE_TYPE_DESC="Select the database type."
 INSTL_DATABASE_USER_DESC="Either a username you created or a username provided by your host."
 INSTL_DATABASE_VALIDATION_ERROR="Check your database credentials, database type, database name or hostname. If you have MySQL 8 installed then please read this <a href=\"https://docs.joomla.org/Joomla_and_MySQL_8#Workaround_to_get_Joomla_working_with_MySQL_8\" target=\"_blank\">wiki</a> for more information."

installation/language/en-US/en-US.ini

@@ -65,6 +65,7 @@ INSTL_DATABASE_NO_SCHEMA="No database schema exists for this database type."
 INSTL_DATABASE_PASSWORD_DESC="Either a password you created or a password provided by your host."
 INSTL_DATABASE_PREFIX_DESC="Enter a table prefix or use the randomly generated one."
 INSTL_DATABASE_PREFIX_MSG="The table prefix must start with a letter, optionally be followed by alphanumeric characters and by an underscore"
+INSTL_DATABASE_RESPONSE_ERROR="The latest request returned an invalid response:"
 INSTL_DATABASE_TYPE_DESC="Select the database type."
 INSTL_DATABASE_USER_DESC="Either a username you created or a username provided by your host."
 INSTL_DATABASE_VALIDATION_ERROR="Check your database credentials, database type, database name or hostname. If you have MySQL 8 installed then please read this <a href=\"https://docs.joomla.org/Joomla_and_MySQL_8#Workaround_to_get_Joomla_working_with_MySQL_8\" target=\"_blank\">wiki</a> for more information."

installation/template/index.php

@@ -49,6 +49,8 @@
 Text::script('INSTL_PROCESS_BUSY');
 Text::script('INSTL_FTP_SETTINGS_CORRECT');
 
+Text::script('INSTL_DATABASE_RESPONSE_ERROR');
+
 // Load strings for translated messages (directory removal)
 Text::script('INSTL_REMOVE_INST_FOLDER');
 Text::script('INSTL_COMPLETE_REMOVE_FOLDER');

installation/template/js/setup.js

@@ -83,8 +83,15 @@ Joomla.checkDbCredentials = function() {
     perform: true,
     headers: {'Content-Type': 'application/x-www-form-urlencoded'},
     onSuccess: function(response, xhr){
-      response = JSON.parse(response);
       var loaderElement = document.querySelector('joomla-core-loader');
+      try {
+        response = JSON.parse(response);
+      } catch (e) {
+        loaderElement.parentNode.removeChild(loaderElement);
+        Joomla.renderMessages({'error': [Joomla.JText._('INSTL_DATABASE_RESPONSE_ERROR'), response]});
+
+        return false;
+      }
 
       if (response.messages) {
         Joomla.renderMessages(response.messages);

installation/template/js/template.js

@@ -185,10 +185,19 @@
       data: data,
       perform: true,
       onSuccess: function(response, xhr){
-        response = JSON.parse(response);
-        Joomla.replaceTokens(response.token);
         var spinnerElement = document.querySelector('joomla-core-loader');
 
+        try {
+          response = JSON.parse(response);
+        } catch (e) {
+          spinnerElement.parentNode.removeChild(spinnerElement);
+          Joomla.renderMessages({'error': [Joomla.JText._('INSTL_DATABASE_RESPONSE_ERROR'), response]});
+
+          return false;
+        }
+
+        Joomla.replaceTokens(response.token);
+
         if (response.error === true)
         {
           spinnerElement.parentNode.removeChild(spinnerElement);