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File Upload and download
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I. Configuration information for php.ini
File_uploads = ON/off Allow file upload
UPLOAD_MAX_FILESIZE=2M the maximum size of uploaded files
Post_max_size = maximum size allowed for 8M post data
Upload_tmp_dir the temporary directory where the uploaded files are placed
Second, the client upload settings
1, the form must be post submission
2. Upload type: enctype= "Multipart/form-data"
3, upload the use of the form items
<input type= "File" name= ":" >
4. (optional) Upload size limit form hidden fields: max_file_size,
<input type= "hidden" name= "max_file_size" value= "size byte"/>
Note: This field must precede the File entry field (usually after the form tag)
<HTML><Head><title>File Upload</title></Head><Body> <formAction= ' upload.php 'Method= ' POST 'enctype= ' Multipart/form-data '> <inputtype= ' hidden 'name= ' max_file_size 'value= ' 1000000 '>Select File:<inputtype= ' file 'name= ' myfile '> <inputtype= ' Submit 'value= ' upload file '> </form></Body></HTML>
Third, on the server side through the PHP processing upload
1. Use $_files global array to receive upload information
In each uploaded file, there are 5 attributes in the $_files:
Error: The wrong number of uploads: 0--4
0: Indicates that no errors have occurred.
1: The uploaded file exceeds the value of the Upload_max_filesize option limit in php.ini.
2: Indicates that the upload file size exceeds the maximum value specified by the Max_file_size element of the HTML form's hidden field property.
3: Indicates that the file is only partially uploaded.
4: Indicates that no files were uploaded.
6: Unable to find temp folder
7: File Write Failed
Name: The file name of the upload
Size: Sizes of files
Type: File type
Tmp_name: Temp File
2, determine whether to upload files is_uploaded_file ()
1<?PHP2 //determine if a file can be uploaded to the server3 //$_file[' myfile ' [' ERROR '] 0 means upload is successful4 if($_files[' MyFile '] [' ERROR '] > 0){5 Echo' Upload error ';6 Switch($_files[' MyFile '] [' Error ']){7 Case1: die(' Upload file size exceeds the contract value in PHP config file: upload_max_filesize ');8 Case2: die(' upload size exceeds the contract value in the form: Max_file_size '));9 Case3: die(' files are only partially uploaded ');Ten Case4: die(' No files uploaded '); One default: die(' Unknown error '); A } - } -?>
3. Move the uploaded file to the new location Move_uploaded_file ()
1<?PHP2 $path= './uploads '3 if(Is_uploaded_file($_files[' MyFile '] [' Tmp_name '])){4 if(!Move_uploaded_file($_files[' MyFile '] [' Tmp_name '],$path. ‘/‘ .$filename)){5 die(' cannot move files to the specified directory ');6 }7 }8?>
4, determine whether the type can be uploaded
1<?PHP2 //set the allowed upload type3 $allowtype=Array(' gif ', ' jpg ', ' png ');4 //split the fractional group and remove the suffix name5 $cs=Array_pop(Explode(‘.‘,$FILES[' MyFile '] [' Name ']));6 //determines whether the type of upload is allowed by judging the file's extension7 if(!In_array($cs,$allowtype)){8 die("The suffix name is {$cs}, not a file type allowed to upload ");9 }Ten?>
5. Determine the allowable upload file size
1 <? PHP 2 $size = 100000; 3 if ($FILES$size) {4 die (' exceeds the allowable {$size} byte size '): 5 }6 ?>6. System definition file name after uploading
1 <? PHP 2 // For system security, also for files with the same name will not be overwritten, after uploading the file name using the system definition 3 $cs Array_pop (explode('. ',$FILES[' myfile '] [' name '])); 4 $filename Date (' Ymdhis '). Rand $cs ; 5 }6 ?>Iv. Upload Multiple files
As long as the client provides several input forms of type file, and sets a different Name property value
1 <HTML>2 <Head><title>File Upload</title></Head>3 <Body>4 <formAction= ' upload.php 'Method= ' POST 'enctype= ' Multipart/form-data '>5 <inputtype= ' hidden 'name= ' max_file_size 'value= ' 1000000 '>6Select File 1:<inputtype= ' file 'name= ' myfile[] '><BR>7Select File 2:<inputtype= ' file 'name= ' myfile[] '><BR>8Select File 3:<inputtype= ' file 'name= ' myfile[] '><BR>9 <inputtype= ' Submit 'value= ' upload file '>Ten </form> One </Body> A </HTML>
V. File download
1<?PHP2 Header("Content-type: Type");//Specify the type of file to download3 Header("Content-disposition:attachment;filename= file name");//Specify the downloaded file description4 Header("Content-length: File Size");//Specify the file size to download5 ReadFile("./uploads/".$picname);//read and output picture content6?>
Vi. Mind Mapping
"Code Learning" php File upload and download
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