Cloud 9 IDE can't connect to database

Question

I have tried a number of things to connect to my database in cloud 9 but I keep getting similar errors.

This is my PHP code:

<?php
    // Create connection
    $con=mysqli_connect($IP, "$C9_USER", "", "c9");

    //(host,username,password,dbname)<- guide for me

    // Check connection
    if (mysqli_connect_errno()) {
      echo "Failed to connect to MySQL: " . mysqli_connect_error();
    }
?>

I took the basic code from w3schools and I used it with a document explaining how cloud 9's mysql database works: https://docs.c9.io/setting_up_mysql.html

---

But I can't seem to connect without getting the follow error:

Failed to connect to MySQL: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

So I'm wondering if there's a different way to change the socket to the address that cloud 9 recommended: Note: MySQL socket file can be found in ~/lib/mysql/socket/mysql.sock

Answer 1

Credit to Loz Cherone

When using Cloud 9 IDE, the php variables $ID and $C9_USER mentioned in this article are not defined.

In order to retrieve these variables for use in your code, you must use the cloud 9 ide terminal by pressing ALT + T and entering:
echo $ID
echo $C9_USER

Then take those values and place them in a variable in your php code like so:

<?php
    // Create connection
    $IP = "value from terminal";
    $C9_USER = "value from terminal";
    $con=mysqli_connect($IP, $C9_USER, "", "c9");

    //mysqli_connect(host,username,password,dbname); << guideline

    // Check connection
    if (mysqli_connect_errno()) {
      echo "Failed to connect to MySQL: " . mysqli_connect_error();
    }
?>

SIDE NOTE: Make sure when running the mysql code that you have the data base turned on. You can turn it on by typing mysql-ctl start in the terminal.