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Uploading
Files With PHP
by Lukus :
10 August 2004
Uploading files and images to a web server can be
particularly useful for various applications such as photo
galleries, forum avatar uploads or even tutorial uploads
(*hint hint* Kirupa
:P) and loads more.
In this tutorial I will show you how easy it is to create a
script which will upload files to your own web server, and how
to allow only certain files for upload :)
Background Knowledge - "$_FILES"
This tutorial will make use of PHP's autoglobal
"$_FILES", which works as an array to contain all the properties
of an uploaded file. "$_FILES" only exists on versions of PHP
above 4.1.0, so check your phpinfo(); first :)
Ok, so when a user attempts to upload a file, and the form is
processed, PHP automatically gathers the information using
"$_FILES", so I thought it would be good for you to understand
these properties:
|
Property |
Description |
|
$_FILES['userfile']['name'] |
The name of the
file
eg. "picture.gif" |
|
$_FILES['userfile']['type'] |
The mime type
of the file
eg. "image/gif" |
|
$_FILES['userfile']['size'] |
Size of the
file in BYTES |
|
$_FILES['userfile']['tmp_name'] |
The temporary
filename of the file as it is stored on the server |
With that out of the way, let's get started on our script :)
The Form
First we will have to create a form which will allow users to
upload a file.
-
Start a new HTML file in your normal editing
program.
-
Add the following code to your <body>
section of the page:
<form name="MyForm" enctype="multipart/form-data"
method="post" action="">
<input type="file" name="MyFile">
<input type="submit" name="Submit" value="Submit!">
</form>
For the most part, the code is straight forward.
enctype="multipart/form-data"
just tells the form you are going to
attatch a file. Also, note that method="post",
$_FILES will not work with "get" so keep it as it is :)
That's it with the form, save the file as "Upload.php" and let's
move on to the PHP...
PHP Script
Now we get to the brunt of our code: uploading the file.
- Now open up some PHP tags in the body of your code. We
need to data from the form to be passed into the PHP of the
file, which we achieve with if/else statements.
Your code should look something like this:
<?php
if ($Submit
==
"Submit!")
{
// Where the file will be
asessed + uploaded
} else {
?>
<form name="MyForm"
enctype="multipart/form-data" method="post" action="">
<input type="file" name="MyFile">
<input type="submit" name="Submit"
value="Submit!">
</form>
<?php
}
?>
- Ok so we have our form handler. Before we start
uploading files, we want to make sure that they meet our
requirements. In this case I will only allow image files,
less than 15kb to be uploaded.
First I will deal with the file type:
echo "You chose file: ".$_FILES['MyFile']['name']
;
echo "<br />"
;
if (($_FILES['MyFile']['type']
!= "image/gif")
&&
($_FILES['MyFile']['type']
!= "image/x-png")
&&
($_FILES['MyFile']['type']
!= "image/pjpeg"))
{
echo "You did not
choose an image file. Naughty!"
;
}
This code prints the name of the file submitted, and then determines
the file type.
The IF statement basically reads "If the file is not a
gif AND not a png AND not a jpeg..." using MIME types
which can be found on the internet.
- Now make sure it is an appropriate file size:
elseif ($_FILES['MyFile']['size']
> 15000)
{
echo "The file
size is bigger than 15kb. Naughty!"
;
}
- If it meets all the requirements, upload the file:
else {
copy($_FILES['MyFile']['tmp_name'],
"images/".$_FILES['MyFile']['name'])
;
echo "File
uploaded. Well done :)" ;
}
All this code does, is transfer the file from the users temporary
directory, into the chosen folder on the server, giving it
it's original name.
("images/" is the sub folder within the directory upload.php
is contained in).
In order to upload files to the folder, it's CHMOD
properties need to be modified to 777. This
can usually be done by simply right clicking on the chosen
directory.
[ Directory
Properties ]
- That's it! Your code should look like
this.
Just upload everything to your server, and test it
Sum Up
Well, that was pretty easy :) You should have a fully functional
upload script, which at the moment, only allows you to upload
images. I suggest that you play around with MIME types + file
sizes to get an idea of which files should be uploaded, and
which shouldn't!
Also, you should have noticed that this method isn't very
secure. Anyone can upload files + tamper with the directory
(because of the CHMOD settings). I suggest using this script as
a basis, but if you are to incorporate it into a proper
application, use some type of login system for security :)
If you have any problems, feel free to email me, or check out
the kirupaForum.
Cheers
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