With PHP, it is easy to upload files to the server. However, with ease comes danger, so always be careful when allowing file uploads!
Configure The "php.ini" File
First, ensure that PHP is configured to allow file uploads.
In your "php.ini" file, search for the
file_uploads directive, and set it to On:
Create The HTML Form
Next, create an HTML form that allow users to choose the image file they want to upload:
Some rules to follow for the HTML form above:
- Make sure that the form uses method="post"
- The form also needs the following attribute: enctype="multipart/form-data". It specifies which content-type to use when submitting the form
Without the requirements above, the file upload will not work.
Other things to notice:
- The type="file" attribute of the <input> tag shows the input field as a file-select control, with a "Browse" button next to the input control
The form above sends data to a file called "upload.php", which we will create next.
Create The Upload File PHP Script
The "upload.php" file contains the code for uploading a file:
PHP script explained:
- $target_dir = "uploads/" - specifies the directory where the file is going to be placed
- $target_file specifies the path of the file to be uploaded
- $uploadOk=1 is not used yet (will be used later)
- $imageFileType holds the file extension of the file (in lower case)
- Next, check if the image file is an actual image or a fake image
Check if File Already Exists
Now we can add some restrictions.
First, we will check if the file already exists in the "uploads" folder. If it does, an error message is displayed, and $uploadOk is set to 0:
Limit File Size
The file input field in our HTML form above is named "fileToUpload".
Now, we want to check the size of the file. If the file is larger than 500KB, an error message is displayed, and $uploadOk is set to 0:
Limit File Type
The code below only allows users to upload JPG, JPEG, PNG, and GIF files. All other file types gives an error message before setting $uploadOk to 0:
Complete Upload File PHP Script
The complete "upload.php" file now looks like this: