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1.) A visitor counter

Create a php file that outputs "You are visitor: $n" (where $n is the number of page hits) using the following functions:

  • file_exists
  • file_get_contents
  • file_put_contents
  • echo

Unique hit variant

Only add to the page hit counter if this IP address has never been seen before. Record the seen IP's in a separate data file.

Read:

Also use functions:

  • in_array
  • serialize and unserialize (easier), or
  • pack, unpack and ip2long (more challenging)

2.) A comments form

  • view-comments.php: Outputs the comments stored in a data file, along with a form to post new comments. Displays a friendly message if no comments.
  • post-comment.php: Appends a new comment to the data file, and redirects to view-comments.php if successful. Displays a friendly error message if the comment parameter is missing.

Read:

  • [$_POST] 3
  • [User Submitted Data] 4

Use functions:

  • empty
  • htmlspecialchars
  • file_exists
  • file_get_contents
  • file_put_contents
  • serialize
  • unserialize
  • header

Object-Oriented variant

Instead of using a hard-coded data file name to store the comments, implement the following interface in a class to manipulate $articleID.dat

<?php

interface ArticleCommentInterface {
  public function __construct($articleID);
  public function getComments();
  public function addComment($comment);
}

Read:

3.) Now with MySQL

Repeat lessons 1 and 2, but with MySQL database server to replace the data files. Should display the error message from DB server on connection or query error. For extra fun, use the object-oriented mysqli interface.

Read:

  • [Database Security: SQL Injection] SQL_INJECTION
  • [MySQLi: Dual procedural and object-oriented interface] 5
  • [3.3 Creating and Using a Database] 6

Use functions:

  • mysqli_connect
  • mysqli_connect_errno
  • mysqli_connect_error
  • mysqli_query
  • mysqli_real_escape_string
  • mysqli_error
  • mysqli_fetch_assoc
  • mysqli_free_result
  • mysqli_close

Prepared Statement Variant

Instead of using mysqli_query and mysqli_real_escape_string, use the following functions:

  • mysqli_stmt_init
  • mysqli_stmt_bind_param
  • mysqli_stmt_prepare
  • mysqli_stmt_execute
  • mysqli_stmt_bind_result
  • mysqli_stmt_fetch
  • mysqli_stmt_close