Todo list PHP

💎 The application

This repository contains a partially implemented todo list written in PHP, HTML and CSS. The application connects to a MySQL database. All the code is in the index.php file.

💎 Tips

• 💎 You may run this application on your local machine with MAMP or WAMP, or with a local installation of PHP and MySQL if you already have them.

• 💎 This repository contains a todolist.sql file you can use to create the database for this project. If you use MAMP, you can run its contents from MAMP's phpMyAdmin interface.

  You should change the password in the SQL before running it.

• 💎 Need help choosing a good password? Don't use something that is hard to remember. You're better off using a passphrase (here's a French version).

• 💎 You can update the constants at the top of index.php to match your local installation:

  • The value of BASE_URL must match the URL at which the application is available.

    For example, if you use MAMP and put this repository in MAMP's htdocs directory, the application will be accessible at http://localhost:8888/comem-archidep-php-todo-exercise/ (with the default ports). In this situation, the value of BASE_URL should be /comem-archidep-php-todo-exercise/.

  • You can change the value of DB_PORT to match your local MySQL port (for example, with MAMP, the default is 8889).

❓ End result

The fully implemented application should look and behave like this: https://todolist.archidep.ch

💥 Troubleshooting

Note that PHP errors may appear only in your PHP error log, or also in your browser. Whether they appear in your browser depends on parameters in your php.ini configuration, such as error_reporting.

💥 You have an error in your SQL syntax [...] near BY

The todolist.sql file contains the following query:

CREATE USER IF NOT EXISTS 'todolist'@'localhost' IDENTIFIED WITH mysql_native_password BY 'chAngeMeN0w!';

The WITH mysql_native_password portion of this query is required for some older versions of MySQL. If you get a syntax error message when you run it, simply remove that part and use only IDENTIFIED BY.

💥 Uncaught PDOException [...] Access denied

If you see an error that looks like this displayed in your browser or in the PHP error log:

PHP Fatal error:
  Uncaught PDOException: SQLSTATE[HY000] [1045]
  Access denied for user 'todolist'@'localhost' (using password: YES)

It means that you are not using the correct database connection parameters. Make sure that the following parameters are configured correctly:

• The DB_PASS parameter must be the password you used when you created the todolist user with the SQL in the todolist.sql file.
• The DB_PORT parameter must be the port on which you MySQL server is listening. The default MySQL port is 3306, but it may be different depending on your installation method. For example, MAMP uses port 8888 by default.

You may also have made a mistake when creating the MySQL user. If you are not sure, you can delete the user by running the query DROP USER 'todolist'@'localhost';, then re-run the CREATE USER ... and GRANT ALL PRIVILEGES ... queries of the todolist.sql file.

💥 Invalid argument supplied for foreach()

If you see an error that looks like this displayed in your browser or in the PHP error log:

PHP Warning: Invalid argument supplied for foreach()

It is simply because you have not yet implemented the SELECT query in the $selectQuery variable. This makes the $items variable empty, which produces an error in the foreach loop that attempts to iterate over it to display the todo items.

💥 Adding a todo item redirects to another URL

You have not configured the BASE_URL parameter correctly. This value is used in the form's action attribute when creating a todo item.

The correct value is the base path under which the application is exposed. For example, if you are accessing the application at http://localhost:8888/comem-archidep-php-todo-exercise/, then BASE_URL should be /comem-archidep-php-todo-exercise/. If you are accessing the application at http://localhost:8888, then BASE_URL should be /.

💥 The application displays correctly but modifications are not taken into account

You may have configured your BASE_URL without a trailing slash (e.g. /comem-archidep-php-todo-exercise instead of /comem-archidep-php-todo-exercise/).

The Apache web server (in MAMP or equivalent) will not treat requests to those two paths in the same way:

• The first path /comem-archidep-php-todo-exercise will probably be redirected to /comem-archidep-php-todo-exercise/ with a standard Apache configuration. Any form data submitted in the request will be lost in the redirection.
• The second path /comem-archidep-php-todo-exercise/ refers to the directory by the same name. In that case, a standard Apache configuration will probably execute the index.php page in that directory.

Without the trailing slash, your application may display correctly, but form submission may be broken.