File upload and download learning notes (1)---File Upload principle and configuration

A: The principle: To upload the client's files to the server-side temporary directory , and then move the server-side temporary files to the specified directory .

II: Configuration of the client

1. form must be a POST method
2. form must be added enctype= "Multipart/form-data" property

Both are indispensable.

Three: Move temporary files to the specified directory

Two methods: 1:move_uploaded_file ($filename, $destination)

2:copy ($source, $dest)

Four: Configuration in the php.ini

When searching for uploads in php.ini, you will see the configuration of the uploads module

The first item: File_uploads=on Open File Upload function

Second item: upload_tmp_dir= "C:\xampp\tmp" Temp directory

The third item: upload_max_filesize maximum file size allowed to upload

Item Fourth: Post_max_size the size of data passed through the Post method

Fifth item: Max_file_uploads=20 upload up to 20 files at a time

About the configuration of resources
Max_execution_time=30 the maximum allowable execution time, in seconds, before the script parser terminates. Prevent the program from writing poorly and take advantage of server resources
max_input_time=60 script parsing the maximum time for input data post, GET, etc.
Max_input_nesting_level = 64 Sets the nesting depth of the input variable
Memory_limit =128m Maximum single thread (Web request) for independent memory usage
Max_input_vars = 1000 How many input variables are accepted

V: Error number resolution

0 upload successfully uploaded to temp directory successfully
1 exceeds the value of upload_max_filesize
2 exceeded the value specified by max_file_size (form)
3 files are only partially uploaded
4 No files were uploaded
6 Temp directory not found
7 File Write Failed
8 uploaded file interrupted by php extension

File upload and download learning notes (1)---File Upload principle and configuration