For the sake of website security, PHP files will not be uploaded. If someone enters your background and uploads a PHP file, all the source code of your website will be saved to him, directly package your code. Therefore, you must control the upload directory and file type. Generally, you can only upload images.
Create a file upload form
It is very useful to allow users to upload files from forms.
See the following HTML form for uploading files:
Copy codeThe Code is as follows:
<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>
Pay attention to the following information about this form:
<Form> the enctype attribute of a tag specifies the content type to be used when submitting a form. When a form requires binary data, such as file content, use multipart/form-data ".
<Input> the type = "file" attribute of the tag specifies that the input should be processed as a file. For example, when previewing in a browser, a browser button is displayed next to the input box.
Note: allowing users to upload files is a huge security risk. Only trusted users are allowed to upload files.
Create upload script
The "upload_file.php" file contains the code for uploading files:
Copy codeThe Code is as follows:
<? 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 Array $ _ FILES of PHP, you can upload FILES from the client computer to a remote server.
The first parameter is the input name of the form, and the second subscript can be "name", "type", "size", "tmp_name" or "error ". Like this:
Copy codeThe Code is as follows:
$ _ FILES ["file"] ["name"]-name of the uploaded file
$ _ FILES ["file"] ["type"]-type of the file to be uploaded
$ _ FILES ["file"] ["size"]-size of the uploaded file, in bytes
$ _ FILES ["file"] ["tmp_name"]-name of the temporary copy of the file stored on the server
$ _ FILES ["file"] ["error"]-error code caused by file Upload
This is a very simple File Upload method. Based on security considerations, you should add restrictions on which users have the right to upload files.
Upload restrictions
In this script, we have added restrictions on file upload. You can only upload. gif or. jpeg files. The file size must be smaller than 20 kb:
Copy codeThe Code is as follows:
<? Php
If ($ _ FILES ["file"] ["type"] = "image/gif ")
| ($ _ FILES ["file"] ["type"] = "image/jpeg ")
| ($ _ FILES ["file"] ["type"] = "image/pjpeg "))
& ($ _ FILES ["file"] ["size"] <20000 ))
{
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 ";
}
?>
Note: For IE, the jpg file type must be pjpeg and for FireFox, it must be jpeg.
Save the uploaded file
In the above example, a temporary copy of the uploaded file is created in the PHP temporary folder on the server.
The temporary copy file will disappear at the end of the script. To save the uploaded file, we need to copy it to another location:
Copy codeThe Code is as follows:
<? Php
If ($ _ FILES ["file"] ["type"] = "image/gif ")
| ($ _ FILES ["file"] ["type"] = "image/jpeg ")
| ($ _ FILES ["file"] ["type"] = "image/pjpeg "))
& ($ _ FILES ["file"] ["size"] <20000 ))
{
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 above script checks whether the file already exists. If it does not exist, copy the file to the specified folder.
Note: In this example, the file is saved to a new folder named "upload.
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