Guide to PHP and MySQL (University at Buffalo Version)

Chapter 7: Working With Files

File Input/Output (I/O)

PHP provides many functions for working with files.

Managing a File Handle Using the `fopen()` and `fclose()` Functions

To work with a file using PHP you need to create a file handle using the fopen() function. To destroy a file handle use the fclose() function.

Reading a File Using the PHP fscanf() Function

You can use the fscanf() function to read a file into an array one line at a time.

<?php
$fh = fopen("socsecurity.txt", "r");
// Parse each SSN in accordance with integer-integer-integer format.
while ($user = fscanf($fh, "%d-%d-%d")) {
list ($part1, $part2, $part3) = $user;
echo("SSN = $part1-$part2-$part3 \n");
}
fclose($fh);
?>

Figure 7-1: The fopen(), fscanf() and fclose() Functions

SSN = 123-45-6789
SSN = 234-56-7890
SSN = 345-67-8901

Figure 7-2: The fopen(), fscanf() and fclose() Output

Reading a CSV File Using the PHP `fgetcsv()` Function

You can use the fgetcsv() function to read a file one line at a time.

<?php
$fh = fopen("subscribers.csv", "r");
// Parse each of comma-separated values.
$thisLine = "";
while (list ($name, $email, $phone) = fgetcsv($fh, 1024, ",")) {
$thisLine .= "Name: $name Email: ($email) Telephone Number: $phone \n";
}
$thisLine .= "";
echo($thisLine);
fclose($fh);
?>

Figure 7-3: The fgetcsv() Function

Name: Jim Gerland Email: (gerlanjr@buffalostate.edu) Telephone Number: (716)123-4567
Name: Jim Gerland Email: (gerlnd@buffalo.edu) Telephone Number: (716)456-7890
Name: Jim Gerland Email: (jim.gerland@thegerlands.org) Telephone Number: (716)789-1234

Figure 7-4: The fgetcsv() Output

Reading a File Using the PHP fgets() Function

You can use the fgets() function to read a file one line at a time.

<?php
$fh = fopen("users.txt", "rt"); // r = read from the beginning; t = Windows translation mode
// Read and write each line of a file.
while (!feof($fh)) {
echo(fgets($fh) . " ");
}
fclose($fh);
?>

Figure 7-5: The fgets() Function

Ale ale@example.com
Nicole nicole@example.com
Laura laura@example.com

Figure 7-6: The fgets() Output

Reading a File Using the PHP file() Function

You can also use the file() function to read a file into an array without using file handle to open or close the file.

<?php
$users = file("users.txt");
foreach ($users as $user) {
list($name, $email) = explode(" ", $user);
// Remove newline from $email
$email = trim($email);
echo("<a href=\"mailto:$email\">$name</a> \n");
}
?>

Figure 7-7: The file() Function

Ale
Nicole
Laura

Figure 7-8: The file() Output

Writing a File Using the PHP fwrite() Function

You can use the "a+" file mode on the fopen() function to append to a file. You can then use the fwrite() function to write to that file.

<?php
$fh = fopen("users.txt", "a+"); // open the file for append
echo("Adding $subscriberInfo to the end of the users.txt file");
fwrite($fh, "\n$subscriberInfo");
fclose($fh);
?>

Figure 7-9: The fwrite() Function

Adding Jim gerlanjr@buffalostate.edu to the end of the users.txt file

Figure 7-10: The fwrite() Output

Task - Create a Web Page That Reads and Writes a File

For this Assignment you will create a web page named io.php on your local web server. This web page should:

Use appropriate HTML5, CSS-styled tags that identify this as your web page including your name and a brief paragraph describing how you approached solving this problem.
Use PHP to generate the following HTML:
- An appropriate <!doctype html> tag indicating that this is an HTML5 web page.
- Appropriate <html>, <head>, and <title> tags to give your page a title that contains your name. Appropriate <meta> tags with content describing keywords for the author, text-editor used, and SEO information. Use your vars.php file.
Use PHP to:
- Use appropriate PHP comments throughout your code.
- Add a function to your functions.php file that reads the text file cda215_io.txt.
- This function should use PHP array to store records (each line is a "record").
- This function should use a PHP Loop to walk through the months names array and generate HTML5/CSS to display the table.
- This function should use a PHP conditional (if) test to (use the mod (%) operator) determine whether the row is odd or even and use appropriate CSS to make the even rows a different background/foreground color than the odd rows.
- Create a function that writes the text file cda215_ior.txt (reverse order).
- This function should use PHP for loop to walk through the array in reverse order and write each array entry (line/record) to the cda215_ior.txt file.
Appropriate HTML5, CSS-styled tags that identify this as your web page including your name and a brief paragraph describing how you approached solving this problem.
You should use appropriately identified and styled <div> tags for the various areas of your page layout.
Modify your JavaScript in your index.html file that uses an array of the Assignments for this course to display an ordered list of these assignments to convert the entry for this assignment to a web link that allows me download and save your files and grade your work.