你是否想过网站如何应用PHP构建其文件上传零碎？在这里, 咱们将理解文件上传过程。你可能会想到一个问题-“咱们是否能够通过该零碎上传任何类型的文件？”。答案是能够的, 咱们能够上传具备不同扩展名的文件。
让咱们制作一个HTML表单, 用于将文件上传到服务器。
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>File Upload Form</title>
</head>
<body>
<form action="file-upload-manager.php" method="post" enctype="multipart/form-data">
<!--multipart/form-data ensures that form data is going to be encoded as MIME data-->
<h2>Upload File</h2>
<label for="fileSelect">Filename:</label>
<input type="file" name="photo" id="fileSelect">
<input type="submit" name="submit" value="Upload">
<!-- name of the input fields are going to be used in our php script-->
<p><strong>Note:</strong>Only .jpg, .jpeg, .png formats allowed to a max size of 2MB.</p>
</form>
</body>
</html>当初, 该写一个可能解决文件上传零碎的php脚本了。
file-upload-manager.php
<?php
// Check if the form was submitted
if ( $_SERVER [ "REQUEST_METHOD" ] == "POST" )
{
// Check if file was uploaded without errors
if (isset( $_FILES [ "photo" ]) && $_FILES [ "photo" ][ "error" ] == 0)
{
$allowed_ext = array ( "jpg" => "image/jpg" , "jpeg" => "image/jpeg" , "gif" => "image/gif" , "png" => "image/png" );
$file_name = $_FILES [ "photo" ][ "name" ];
$file_type = $_FILES [ "photo" ][ "type" ];
$file_size = $_FILES [ "photo" ][ "size" ];
// Verify file extension
$ext = pathinfo ( $filename , PATHINFO_EXTENSION);
if (! array_key_exists ( $ext , $allowed_ext ))
die ( "Error: Please select a valid file format." );
// Verify file size - 2MB max
$maxsize = 2 * 1024 * 1024;
if ( $file_size > $maxsize )
die ( "Error: File size is larger than the allowed limit." );
// Verify MYME type of the file
if (in_array( $file_type , $allowed_ext ))
{
// Check whether file exists before uploading it
if ( file_exists ( "upload/" . $_FILES [ "photo" ][ "name" ]))
echo $_FILES [ "photo" ][ "name" ]. " is already exists." ;
else
{
move_uploaded_file( $_FILES [ "photo" ][ "tmp_name" ], "uploads/" . $_FILES [ "photo" ][ "name" ]);
echo "Your file was uploaded successfully." ;
}
}
else
{
echo "Error: Please try again." ;
}
}
else
{
echo "Error: " . $_FILES [ "photo" ][ "error" ];
}
}
?>在下面的脚本中, 一旦咱们提交了表单, 当前咱们就能够通过PHP超全局关联数组$ _FILES访问信息。除了应用$ _FILES数组的模式外, 许多内置函数也起着次要作用。上传完文件后, 在脚本中咱们将查看服务器的申请办法, 如果它是POST, 则它将持续进行, 否则零碎将引发谬误。稍后, 咱们拜访了$ _FILES数组以获取文件名, 文件大小和文件类型。一旦取得了这些信息, 就能够验证文件的大小和类型。最初, 咱们在要上传文件的文件夹中搜寻, 以查看文件是否曾经存在。如果没有, 咱们曾经应用move_uploaded_file()将文件从长期地位挪动到服务器上的所需目录, 咱们就实现了。
输入如下
更多后端开发相干内容请参考：lsbin – IT开发技术：https://www.lsbin.com/
查看以下更多文件上传的相干的内容：
- Node.js中的formidable模块上传文件：https://www.lsbin.com/2898.html
- Node.js应用Sharp包进行图像上传：https://www.lsbin.com/1604.html
- PHP ftp_put()函数用法：https://www.lsbin.com/3352.html
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