Learn PHP for Free

Monday, 5 May 2014

PHP File Upload

With PHP, it is possible to upload files to the server.

Create an Upload-File Form

To allow users to upload files from a form can be very useful.
Look at the following HTML form for uploading files:

<html>
<body>

<form action="upload_file.php" method="post"
enctype="multipart/form-data">
<label for="file">Filename:</label>
<input type="file" name="file" id="file"><br>
<input type="submit" name="submit" value="Submit">
</form>

</body>
</html>

Notice the following about the HTML form above:

The enctype attribute of the <form> tag specifies which content-type to use when submitting the form. "multipart/form-data" is used when a form requires binary data, like the contents of a file, to be uploaded
The type="file" attribute of the <input> tag specifies that the input should be processed as a file. For example, when viewed in a browser, there will be a browse-button next to the input field

Note: Allowing users to upload files is a big security risk. Only permit trusted users to perform file uploads.

Create The Upload Script

The "upload_file.php" file contains the code for uploading a file:

<?php
if ($_FILES["file"]["error"] > 0) {
  echo "Error: " . $_FILES["file"]["error"] . "<br>";
} else {
  echo "Upload: " . $_FILES["file"]["name"] . "<br>";
  echo "Type: " . $_FILES["file"]["type"] . "<br>";
  echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
  echo "Stored in: " . $_FILES["file"]["tmp_name"];
}
?>

By using the global PHP $_FILES array you can upload files from a client computer to the remote server.
The first parameter is the form's input name and the second index can be either "name", "type", "size", "tmp_name" or "error". Like this:

$_FILES["file"]["name"] - the name of the uploaded file
$_FILES["file"]["type"] - the type of the uploaded file
$_FILES["file"]["size"] - the size in bytes of the uploaded file
$_FILES["file"]["tmp_name"] - the name of the temporary copy of the file stored on the server
$_FILES["file"]["error"] - the error code resulting from the file upload

This is a very simple way of uploading files. For security reasons, you should add restrictions on what the user is allowed to upload.

Restrictions on Upload

In this script we add some restrictions to the file upload. The user may upload .gif, .jpeg, and .png files; and the file size must be under 20 kB:

<?php
$allowedExts = array("gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = end($temp);

if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/jpg")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/x-png")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 20000)
&& in_array($extension, $allowedExts)) {
  if ($_FILES["file"]["error"] > 0) {
    echo "Error: " . $_FILES["file"]["error"] . "<br>";
  } else {
    echo "Upload: " . $_FILES["file"]["name"] . "<br>";
    echo "Type: " . $_FILES["file"]["type"] . "<br>";
    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
    echo "Stored in: " . $_FILES["file"]["tmp_name"];
  }
} else {
  echo "Invalid file";
}
?>

Saving the Uploaded File

The examples above create a temporary copy of the uploaded files in the PHP temp folder on the server.
The temporary copied files disappears when the script ends. To store the uploaded file we need to copy it to a different location:

<?php
$allowedExts = array("gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = end($temp);

if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpeg")
|| ($_FILES["file"]["type"] == "image/jpg")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/x-png")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 20000)
&& in_array($extension, $allowedExts)) {
  if ($_FILES["file"]["error"] > 0) {
    echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
  } else {
    echo "Upload: " . $_FILES["file"]["name"] . "<br>";
    echo "Type: " . $_FILES["file"]["type"] . "<br>";
    echo "Size: " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
    echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br>";
    if (file_exists("upload/" . $_FILES["file"]["name"])) {
      echo $_FILES["file"]["name"] . " already exists. ";
    } else {
      move_uploaded_file($_FILES["file"]["tmp_name"],
      "upload/" . $_FILES["file"]["name"]);
      echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
    }
  }
} else {
  echo "Invalid file";
}
?>

The script above checks if the file already exists, if it does not, it copies the file to a folder called "upload".

PHP File Handling

The fopen() function is used to open files in PHP.

Opening a File

The fopen() function is used to open files in PHP.
The first parameter of this function contains the name of the file to be opened and the second parameter specifies in which mode the file should be opened:

The file may be opened in one of the following modes:

Modes	Description
r	Read only. Starts at the beginning of the file
r+	Read/Write. Starts at the beginning of the file
w	Write only. Opens and clears the contents of file; or creates a new file if it doesn't exist
w+	Read/Write. Opens and clears the contents of file; or creates a new file if it doesn't exist
a	Append. Opens and writes to the end of the file or creates a new file if it doesn't exist
a+	Read/Append. Preserves file content by writing to the end of the file
x	Write only. Creates a new file. Returns FALSE and an error if file already exists
x+	Read/Write. Creates a new file. Returns FALSE and an error if file already exists

Note: If the fopen() function is unable to open the specified file, it returns 0 (false).

Example

The following example generates a message if the fopen() function is unable to open the specified file:

Closing a File

The fclose() function is used to close an open file:

<?php
$file = fopen("test.txt","r");

//some code to be executed

fclose($file);
?>

Check End-of-file

The feof() function checks if the "end-of-file" (EOF) has been reached.
The feof() function is useful for looping through data of unknown length.
Note: You cannot read from files opened in w, a, and x mode!

if (feof($file)) echo "End of file";

Reading a File Line by Line

The fgets() function is used to read a single line from a file.
Note: After a call to this function the file pointer has moved to the next line.

Example

The example below reads a file line by line, until the end of file is reached:

<?php
$file = fopen("welcome.txt", "r") or exit("Unable to open file!");
//Output a line of the file until the end is reached
while(!feof($file)) {
echo fgets($file). "<br>";
}
fclose($file);
?>

Reading a File Character by Character

The fgetc() function is used to read a single character from a file.
Note: After a call to this function the file pointer moves to the next character.

Example

The example below reads a file character by character, until the end of file is reached:

<?php
$file=fopen("welcome.txt","r") or exit("Unable to open file!");
while (!feof($file)) {
echo fgetc($file);
}
fclose($file);
?>

PHP Filesystem Reference

For a full reference of the PHP filesystem functions, visit our PHP Filesystem Reference.

PHP Include Files

PHP include and require Statements

In PHP, you can insert the content of one PHP file into another PHP file before the server executes it.
The include and require statements are used to insert code written in another file, into the flow of execution.
The include and require are identical, except upon failure:

require will produce a fatal error (E_COMPILE_ERROR) and stop the script
include will only produce a warning (E_WARNING) and the script will continue

So, if you want the execution to go on and show users the output, even if the include file is missing, use the include statement. Otherwise, in case of FrameWork, CMS, or a complex PHP application coding, always use the require statement to include a key file to the flow of execution. This will help avoid compromising your application's security and integrity, just in-case one key file is accidentally missing.
Including files saves a lot of work. This means that you can create a standard header, footer, or menu file for all your web pages. Then, when the header needs to be updated, you can only update the header include file.

Syntax

include 'filename';

or

require 'filename';

PHP include Examples

Example 1

Assume we have a standard footer file called "footer.php", that looks like this:

<?php
echo "<p>Copyright © 1999-" . date("Y") . " W3Schools.com</p>";
?>

To include the footer file in a page, use the include statement:

Example

<html>
<body>

<h1>Welcome to my home page!</h1>
<p>Some text.</p>
<p>Some more text.</p>
<?php include 'footer.php';?>

</body>
</html>

Run example »

Example 2

Assume we have a standard menu file that should be used on all pages.
"menu.php":

echo '<a href="/default.php">Home</a>
<a href="/tutorials.php">Tutorials</a>
<a href="/references.php">References</a>
<a href="/examples.php">Examples</a>
<a href="/about.php">About Us</a>
<a href="/contact.php">Contact Us</a>';

All pages in the Web site should include this menu file. Here is how it can be done:

<html>
<body>

<div class="leftmenu">
<?php include 'menu.php'; ?>
</div>

<h1>Welcome to my home page.</h1>
<p>Some text.</p>

</body>
</html>

Example 3

Assume we have an include file with some variables defined ("vars.php"):

<?php
$color='red';
$car='BMW';
?>

Then the variables can be used in the calling file:

<html>
<body>

<h1>Welcome to my home page.</h1>
<?php include 'vars.php';
echo "I have a $color $car"; // I have a red BMW
?>

</body>
</html>

PHP 5 Date and Time

The PHP date() function is used to format a date and/or a time.

The PHP Date() Function

The PHP date() function formats a timestamp to a more readable date and time.

Syntax

date(format,timestamp)

Parameter	Description
format	Required. Specifies the format of the timestamp
timestamp	Optional. Specifies a timestamp. Default is the current date and time

	A timestamp is a sequence of characters, denoting the date and/or time at which a certain event occurred.

Get a Simple Date

The required format parameter of the date() function specifies how to format the date (or time).
Here are some characters that are commonly used for dates:

d - Represents the day of the month (01 to 31)
m - Represents a month (01 to 12)
Y - Represents a year (in four digits)
1 - Represents the day of the week

Other characters, like"/", ".", or "-" can also be inserted between the characters to add additional formatting.
The example below formats today's date in three different ways:

Example

<?php
echo "Today is " . date("Y/m/d") . "<br>";
echo "Today is " . date("Y.m.d") . "<br>";
echo "Today is " . date("Y-m-d") . "<br>";
echo "Today is " . date("l");
?>

Run example »

PHP Tip - Automatic Copyright Year

Use the date() function to automatically update the copyright year on your website:

Example

Run example »

Get a Simple Time

Here are some characters that is commonly used for times:

h - 12-hour format of an hour with leading zeros (01 to 12)
i - Minutes with leading zeros (00 to 59)
s - Seconds with leading zeros (00 to 59)
a - Lowercase Ante meridiem and Post meridiem (am or pm)

The example below outputs the current time in the specified format:

Example

<?php
echo "The time is " . date("h:i:sa");
?>

Run example »

	Note that the PHP date() function will return the current date/time of the server!

Get Your Time Zone

If the time you got back from the code is not the right time, it's probably because your server is in another country or set up for a different timezone.
So, if you need the time to be correct according to a specific location, you can set a timezone to use.
The example below sets the timezone to "America/New_York", then outputs the current time in the specified format:

Example

<?php
date_default_timezone_set("America/New_York");
echo "The time is " . date("h:i:sa");
?>

Run example »

Create a Date With PHP mktime()

The optional timestamp parameter in the date() function specifies a timestamp. If you do not specify a timestamp, the current date and time will be used (as shown in the examples above).
The mktime() function returns the Unix timestamp for a date. The Unix timestamp contains the number of seconds between the Unix Epoch (January 1 1970 00:00:00 GMT) and the time specified.

Syntax

mktime(hour,minute,second,month,day,year)

The example below creates a date and time from a number of parameters in the mktime() function:

Example

<?php
$d=mktime(11, 14, 54, 8, 12, 2014);
echo "Created date is " . date("Y-m-d h:i:sa", $d);
?>

Run example »

Create a Date From a String With PHP strtotime()

The PHP strtotime() function is used to convert a human readable string to a Unix time.

Syntax

strtotime(time,now)

The example below creates a date and time from the strtotime() function:

Example

<?php
$d=strtotime("10:30pm April 15 2014");
echo "Created date is " . date("Y-m-d h:i:sa", $d);
?>

Run example »

PHP is quite clever about converting a string to a date, so you can put in various values:

Example

<?php
$d=strtotime("tomorrow");
echo date("Y-m-d h:i:sa", $d) . "<br>";

$d=strtotime("next Saturday");
echo date("Y-m-d h:i:sa", $d) . "<br>";

$d=strtotime("+3 Months");
echo date("Y-m-d h:i:sa", $d) . "<br>";
?>

Run example »

However, strtotime() is not perfect, so remember to check the strings you put in there.

More Date Examples

The example below outputs the dates for the next six Saturdays:

Example

<?php
$startdate = strtotime("Saturday");
$enddate = strtotime("+6 weeks",$startdate);

while ($startdate < $enddate) {
echo date("M d", $startdate),"<br>";
$startdate = strtotime("+1 week", $startdate);
}
?>

Run example »

The example below outputs the number of days until 4th of July:

Example

<?php
$d1=strtotime("July 04");
$d2=ceil(($d1-time())/60/60/24);
echo "There are " . $d2 ." days until 4th of July.";
?>

Run example »

Complete PHP Date Reference

For a complete reference of all date functions, go to our complete PHP Date Reference.
The reference contains a brief description, and examples of use, for each function!

PHP 5 Multidimensional Arrays

Earlier in this tutorial, we have described arrays that are a single list of key/value pairs.

However, sometimes you want to store values with more than one key.

This can be stored in multidimensional arrays.

PHP - Multidimensional Arrays

A multidimensional array is an array containing one or more arrays.
PHP understands multidimensional arrays that are two, three, four, five, or more levels deep. However, arrays more than three levels deep are hard to manage for most people.

	The dimension of an array indicates the number of indices you need to select an element. For a two-dimensional array you need two indices to select an element For a three-dimensional array you need three indices to select an element

PHP - Two-dimensional Arrays

A two-dimensional array is an array of arrays (a three-dimensional array is an array of arrays of arrays).
First, take a look at the following table:

Name	Stock	Sold
Volvo	22	18
BMW	15	13
Saab	5	2
Land Rover	17	15

We can store the data from the table above in a two-dimensional array, like this:

$cars = array
(
array("Volvo",22,18),
array("BMW",15,13),
array("Saab",5,2),
array("Land Rover",17,15)
);

Now the two-dimensional $cars array contains four arrays, and it has two indices: row and column.
To get access to the elements of the $cars array we must point to the two indices (row and column):

Example

<?php
echo $cars[0][0].": In stock: ".$cars[0][1].", sold: ".$cars[0][2].".<br>";
echo $cars[1][0].": In stock: ".$cars[1][1].", sold: ".$cars[1][2].".<br>";
echo $cars[2][0].": In stock: ".$cars[2][1].", sold: ".$cars[2][2].".<br>";
echo $cars[3][0].": In stock: ".$cars[3][1].", sold: ".$cars[3][2].".<br>";
?>

Run example »

We can also put a For loop inside another For loop to get the elements of the $cars array (we still have to point to the two indices):

Example

<?php
for ($row = 0; $row < 4; $row++) {
echo "<p><b>Row number $row</b></p>";
echo "<ul>";
for ($col = 0; $col < 3; $col++) {
echo "<li>".$cars[$row][$col]."</li>";
}
echo "</ul>";
}
?>

Run example »

PHP 5 Forms - Validate E-mail and URL

This chapter show how to validate names, e-mails, and URLs.

PHP - Validate Name

The code below shows a simple way to check if the name field only contains letters and whitespace. If the value of the name field is not valid, then store an error message:

$name = test_input($_POST["name"]);
if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
$nameErr = "Only letters and white space allowed";
}

	The preg_match() function searches a string for pattern, returning true if the pattern exists, and false otherwise.

PHP - Validate E-mail

The code below shows a simple way to check if an e-mail address syntax is valid. If the e-mail address syntax is not valid, then store an error message:

$email = test_input($_POST["email"]);
if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {
$emailErr = "Invalid email format";
}

PHP - Validate URL

The code below shows a way to check if a URL address syntax is valid (this regular expression also allows dashes in the URL). If the URL address syntax is not valid, then store an error message:

$website = test_input($_POST["website"]);
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
$websiteErr = "Invalid URL";
}

PHP - Validate Name, E-mail, and URL

Now, the script looks like this:

Example

<?php
// define variables and set to empty values
$nameErr = $emailErr = $genderErr = $websiteErr = "";
$name = $email = $gender = $comment = $website = "";

if ($_SERVER["REQUEST_METHOD"] == "POST") {
if (empty($_POST["name"])) {
    $nameErr = "Name is required";
} else {
    $name = test_input($_POST["name"]);
    // check if name only contains letters and whitespace
    if (!preg_match("/^[a-zA-Z ]*$/",$name)) {
      $nameErr = "Only letters and white space allowed";
    }
}

if (empty($_POST["email"])) {
    $emailErr = "Email is required";
} else {
    $email = test_input($_POST["email"]);
    // check if e-mail address syntax is valid
    if (!preg_match("/([\w\-]+\@[\w\-]+\.[\w\-]+)/",$email)) {
      $emailErr = "Invalid email format";
    }
}

if (empty($_POST["website"])) {
    $website = "";
} else {
    $website = test_input($_POST["website"]);
    // check if URL address syntax is valid (this regular expression also allows dashes in the URL)
    if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
      $websiteErr = "Invalid URL";
    }
}

if (empty($_POST["comment"])) {
    $comment = "";
} else {
    $comment = test_input($_POST["comment"]);
}

if (empty($_POST["gender"])) {
    $genderErr = "Gender is required";
} else {
    $gender = test_input($_POST["gender"]);
}
}
?>

Run example »

The next step is to show how to prevent the form from emptying all the input fields when the user submits the form.

PHP 5 Forms - Required Fields

This chapter show how to make input fields required and create error messages if needed.

PHP - Required Fields

From the validation rules table on the previous page, we see that the "Name", "E-mail", and "Gender" fields are required. These fields cannot be empty and must be filled out in the HTML form.

Field	Validation Rules
Name	Required. + Must only contain letters and whitespace
E-mail	Required. + Must contain a valid email address (with @ and .)
Website	Optional. If present, it must contain a valid URL
Comment	Optional. Multi-line input field (textarea)
Gender	Required. Must select one

In the previous chapter, all input fields were optional.
In the following code we have added some new variables: $nameErr, $emailErr, $genderErr, and $websiteErr. These error variables will hold error messages for the required fields. We have also added an if else statement for each $_POST variable. This checks if the $_POST variable is empty (with the PHP empty() function). If it is empty, an error message is stored in the different error variables, and if it is not empty, it sends the user input data through the test_input() function:

PHP - Display The Error Messages

Then in the HTML form, we add a little script after each required field, which generates the correct error message if needed (that is if the user tries to submit the form without filling out the required fields):

Example

<form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">

Name: <input type="text" name="name">
<span class="error">* <?php echo $nameErr;?></span>
<br><br>
E-mail:
<input type="text" name="email">
<span class="error">* <?php echo $emailErr;?></span>
<br><br>
Website:
<input type="text" name="website">
<span class="error"><?php echo $websiteErr;?></span>
<br><br>
<label>Comment: <textarea name="comment" rows="5" cols="40"></textarea>
<br><br>
Gender:
<input type="radio" name="gender" value="female">Female
<input type="radio" name="gender" value="male">Male
<span class="error">* <?php echo $genderErr;?></span>
<br><br>
<input type="submit" name="submit" value="Submit">

</form>

Run example »

The next step is to validate the input data, that is "Does the Name field contain only letters and whitespace?", and "Does the E-mail field contain a valid e-mail address syntax?", and if filled out, "Does the Website field contain a valid URL?".

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Monday, 5 May 2014

Create an Upload-File Form

Create The Upload Script

Restrictions on Upload

Saving the Uploaded File

Opening a File

Example

Closing a File

Check End-of-file

Reading a File Line by Line

Example

Reading a File Character by Character

Example

PHP Filesystem Reference

PHP include and require Statements

Syntax

PHP include Examples

Example 1

Example

Example 2

Example 3

The PHP Date() Function

Syntax

Get a Simple Date

Example

PHP Tip - Automatic Copyright Year

Example

Get a Simple Time

Example

Get Your Time Zone

Example

Create a Date With PHP mktime()

Syntax

Example

Create a Date From a String With PHP strtotime()

Syntax

Example

Example

More Date Examples

Example

Example

Complete PHP Date Reference

PHP - Multidimensional Arrays

PHP - Two-dimensional Arrays

Example

Example

PHP - Validate Name

PHP - Validate E-mail

PHP - Validate URL

PHP - Validate Name, E-mail, and URL

Example

PHP - Required Fields

PHP - Display The Error Messages

Example