File upload is divided into two parts, the HTML display part and the PHP processing part. The HTML part mainly allows users to select the file to be uploaded, and then through $_FILES in PHP, we can upload the file to the specified directory of the server.
1. Client page
Client configuration
1. Form page
2. The form is sent as post
3. Add enctype="multipart/form-data" to the form form
<body> <form action="" method="post" enctype="multipart/form-data"> <input type="file" name="myfile"> <input type="submit" value="Upload"> </form> </body>
2. Processing page doaction
$_FILES: File upload variable
print_r($_FILES);
$_FILES: Save the uploaded file information
: The name of the uploaded file
: MIME type of uploaded file
3.tmp_name: Temporary file name uploaded to the server
:The size of the uploaded file
: Error number for uploading file
$filename=$_FILES['myfile']['name']; $type=$_FILES['myfile']['type']; $tmp_name=$_FILES['myfile']['tmp_name']; $size=$_FILES['myfile']['size']; $error=$_FILES['myfile']['error'];
Move temporary files on the server to the specified folder
1.move_uploaded_file(temporary file name, 'folder name'.$filename); Move the temporary file on the server to the specified folder, what is the name ($filename), the movement is successful and the movement is false.
move_uploaded_file($tmp_name,"wenjian/".$filename);
("Temporary file name", "File name".$filename) Copy the temporary files on the server to the specified folder
File upload configuration
file_uploads = on,supportHTTPUpload upload_tmp_dir= ,Directory of temporary file saving upload_max_filesize=2M,允许Upload文件的最大值 max_file_uploads=20,允许一次Upload的最大文件数 post_max_size=8M,postThe maximum value of data sent by method
3. Error message processing
When uploading a file fails, judge the error number. Only if it is 0 or UPLOAD_ERR_OK, no error occurs. If the upload is successful,
Below is the crawling error
if($error==UPLOAD_ERR_OK)
{
if(move_uploaded_file($tmp_name,"wenjian/".$filename))
{
echo "document".$filename."Uploaded successfully";
}else
{
echo "document".$filename."Upload failed";
}
}
else
{
//Match error message switch($error)
{
case 1:
echo "The upload file exceeds the value of the upload_max_filesize option in the PHP configuration file";
break;
case 2:
echo "The limit size of form MAX_FILE_SIZE exceeded";
break;
case 3:
echo "The file part is uploaded";
break;
case 4:
echo "No selected upload file";
break;
case 6:
echo "No temporary directory found";
break;
case 7:
case 8:
echo "System Error";
break;
}
}
?>
4. Upload file restrictions
"Client Restrictions:"
Limit the maximum value of uploaded files by hiding the field in the form
<input type="hidden" name="MAX_FILE_SIZE" value="Number of Bytes">
Restrict the type of uploaded files through the accept attribute
<input type="file" name="myfile" accept="MIME type of file">
Server-side restrictions
1. Limit the uploaded file size
2. Restrict uploaded file types
3. Detect whether it is a real image type
4. Detect whether it is uploaded by HTTP POST
5. Determine whether the folder stored on the server is present
6. Prevent overwrites from duplicate names
<?php
$fileinfo=$_FILES["myfile"];
$maxsize=2097152; //Write the maximum number of bytes and calculate it yourself$allowext=array('jpeg','jpg','pnd','gif','wbmp'); //Define the allowed upload file types//1.Judgement error numberif($fileinfo['error']==0)
{
//1.Judge upload file sizeif($fileinfo['size']>$maxsize)
{
exit('Uploading files too large');
}
//2. Determine whether the uploaded file type is in the specified type$ext=strtolower(end(explode(',',$fileinfo['name'])));//Intercept the upload file extension if(!in_array($ext,$allowext)) // Determine whether the extension of the uploaded file is in the definition type {
exit('Illegal File Type');
}
//3. Determine whether the file is uploaded through HTTP POSTif(!is_uploaded_file($fileinfo['tmp_name']))
{
exit('The file is not uploaded through HTTP POST');
}
//4. Detect whether it is the real image type, rather than the one that is considered to be changed$flag=true;
if($flag)
{
if(!getimagesize($fileinfo['tmp_name']))
{
echo "Not a real picture type";
}
}
$path='uploads'; //The file name of the file stored on the server//5. Determine whether the folder stored on the server is there or notif(!file_exists($path))
{
mkdir($path,0777,true);//Create a directory if it does not exist chmod($path,0777);//Add a permission }
//6. Ensure that the file name is unique and prevent overwrite of duplicate names$uniname=md5(uniqid(microtime(true),true)).'.'.$ext; //Name the file name through MD5 encryption and other measures $destination=$path.'/'.$uniname;
if(move_uploaded_file($fileinfo['tmp_name'],$destination)) //Upload file {
echo "File upload successfully";
}else
{
echo "File upload failed";
}
}else
{
//Match error message switch($error)
{
case 1:
echo "The upload file exceeds the value of the upload_max_filesize option in the PHP configuration file";
break;
case 2:
echo "The limit size of form MAX_FILE_SIZE exceeded";
break;
case 3:
echo "The file part is uploaded";
break;
case 4:
echo "No selected upload file";
break;
case 6:
echo "No temporary directory found";
break;
case 7:
case 8:
echo "System Error";
break;
}
}
?>
5. Complete uploading steps
Step 1: Form page content
<body> <form action="" method="post" enctype="multipart/form-data"> //Limit the maximum value of uploaded files through the form hidden domain<input type="hidden" name="MAX_FILE_SIZE" value="Number of Bytes"> //Limit the type of uploaded file through the accept attribute<input type="file" name="myfile" accept="MIME type of file"> </form> </body>
Step 2: Process the interface. Define variables
<?php //$_FILES: File upload variableprint_r($_FILES); //$_FILES: Save the uploaded file information/*: The name of the uploaded file : MIME type of uploaded file 3.tmp_name: Temporary file name uploaded to the server :The size of the uploaded file : Error number for uploading file*/ $filename=$_FILES['myfile']['name']; $type=$_FILES['myfile']['type']; $tmp_name=$_FILES['myfile']['tmp_name']; $size=$_FILES['myfile']['size']; $error=$_FILES['myfile']['error'];
Step 3: Process the server on the page with restrictions and output error information
1. Limit the uploaded file size
2. Restrict uploaded file types
3. Detect whether it is a real image type
4. Detect whether it is uploaded by HTTP POST
5. Determine whether the folder stored on the server is present
6. Prevent overwrites from duplicate names
// Server side restrictions<?php
$fileinfo=$_FILES["myfile"];
$maxsize=2097152; //Write the maximum number of bytes and calculate it yourself$allowext=array('jpeg','jpg','pnd','gif','wbmp'); //Define the allowed upload file types//1.Judgement error numberif($fileinfo['error']==0)
{
//1.Judge upload file sizeif($fileinfo['size']>$maxsize)
{
exit('Uploading files too large');
}
//2. Determine whether the uploaded file type is in the specified type$ext=strtolower(end(explode(',',$fileinfo['name'])));//Intercept the upload file extension if(!in_array($ext,$allowext)) // Determine whether the extension of the uploaded file is in the definition type {
exit('Illegal File Type');
}
//3. Determine whether the file is uploaded through HTTP POSTif(!is_uploaded_file($fileinfo['tmp_name']))
{
exit('The file is not uploaded through HTTP POST');
}
//4. Detect whether it is the real image type, rather than the one that is considered to be changed$flag=true;
if($flag)
{
if(!getimagesize($fileinfo['tmp_name']))
{
echo "Not a real picture type";
}
}
$path='uploads'; //The file name of the file stored on the server//5. Determine whether the folder stored on the server is there or notif(!file_exists($path))
{
mkdir($path,0777,true);//Create a directory if it does not exist chmod($path,0777);//Add a permission }
//6. Ensure that the file name is unique and prevent overwrite of duplicate names$uniname=md5(uniqid(microtime(true),true)).'.'.$ext; //Name the file name through MD5 encryption and other measures $destination=$path.'/'.$uniname;
$destination=inocv("UTF-8","gb2312",$destination); //If there are Chinese characters in the uploaded file name, you need to transcode it, use the inocv function to convert utf-8 to gb2312. if(move_uploaded_file($fileinfo['tmp_name'],$destination)) //Upload file {
echo "File upload successfully";
}else
{
echo "File upload failed";
}
}else
{
Step 4: Match the error message
switch($error)
{
case 1:
echo "The upload file exceeds the value of the upload_max_filesize option in the PHP configuration file";
break;
case 2:
echo "The limit size of form MAX_FILE_SIZE exceeded";
break;
case 3:
echo "The file part is uploaded";
break;
case 4:
echo "No selected upload file";
break;
case 6:
echo "No temporary directory found";
break;
case 7:
case 8:
echo "System Error";
break;
}
}
?>
The above are the complete steps that the editor introduced to you, including restrictions on client and server, crawling error information, and the complete steps. I hope it will be helpful to everyone. If you have any questions, please leave me a message and the editor will reply to everyone in time. Thank you very much for your support for my website!