Week 11 - Development Environment and PHP Built-in Functions and Dates

Installations

In order to continue with labs in this course, it is now required that you setup and configure your development machine fully on your laptop. Those running non-windows machines cannot be supported by your professor (Windows only installations will be supported).

The following software must be installed and configured correctly.

• VS Code and extensions (should already be done)
• Install PostGreSQL (and PGAdmin4) on your local machine and configure it. Instructions Here.
• Install and Configure Apache Web Server - Instructions
• Configure Apache and PHP to run and connect to PostGreSQLInstructions

PHP Functions and Dates

Shared Functions

We have already seen that we can share files across our sites by include'ing them (e.g. our headers and footers files).
We can also “require” files:

• For our sites going forward we will always need database connectivity
• Therefore have a function named db_connect() inside a PHP file that returns the pg_connect() connection resource
• Advantage - makes site easier to support (if you change password or db name) functions.php

Create an includes sub-folder to your folder and create a file called functions.php in that folder. You will also store your head.php, header.php, and footer.php files in this folder as well.

---

functions.php

Add the following code to the functions.php file:

<?php
    function db_connect(){
        $connection = pg_connect("host=127.0.0.1 dbname=YOUR_DB_NAME user=YOUR_USERID password=YOUR_DB_PASSWORD" ); 
        return $connection; 
    }
?>

---

test.php

Create a file called test.php in the includes folder.

<?php
    include "header.php"; //nice to have file, formatting
    require "./includes/functions.php"; 
    /* a must have file, for db functionality (NOTE: this should in reality be placed in the header.php file. Why? */
?>

<!-- somewhere in the page do database stuff -->

<?php
    $conn = db_connect(); // this works because the function exists in the "require"d file
    pg_query($conn, “UPDATE table SET name = 'fred' WHERE id=1”);
    // now can use the $conn connection resource
?>

<?php
    include “footer.php”;
?>

---

PHP functions

int time();

• https://www.php.net/manual/en/function.time.php
• Takes no arguments
• Returns the current time measured in the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT).
• Current time comes from the computer that PHP is running on

Example

time() today ~45-50 years after 1970-1-1 returns approx. 1.5 billion

A week from now would be: $weekFromNow = time( ) + 60*60*24*7;

---

string date ( string $format [, int $timestamp ] )

Returns a string formatted according to the given format string using the given integer timestamp or the current time if no timestamp is given. In other words, timestamp is optional and defaults to the value of time().

• https://www.php.net/manual/en/function.date.php

$sql = "UPDATE users SET last_access = '". date("Y-m-d", time()) . "' WHERE id = '".$login."'";

Creates:

UPDATE users SET last_access = '2018-03-02' WHERE id = 'jdoe'

Another useful function of the date(); function is you can grab specific fields off of the optional timestamp

<?php echo date('Y'); ?>

NOTE: capital Y will display the current year as a 4-digit number

---

Login Functionality

<?php //embed in a page with a two input box (named id and pass) form 
    require "./includes/functions.php";
    $login = $_POST['id'];
    $password = $_POST['pass'];
    $conn = db_connect();
    $sql = "SELECT first_name, last_name, email_address, last_access FROM 
    users WHERE id = '".$login."' AND password= '".$password."'";
    //Note: the above is not a secure way to do this but ok for first learning

    $results = pg_query($conn, $sql);
    if(pg_num_rows($results)) { 
            //not zero means something was found
            //user found, use pg_fetch_result to pull user specific info to display
    } else {
        //user not found, check for just login id
        $sql = "SELECT * FROM users WHERE id = '".$login."'";
        $results = pg_query($conn, $sql);
        if(!pg_num_rows($results)) { //user not found, empty $login to unstick it
            $login = ""; //when echo''ed in the form
        }
    }
?>