Simple interaction between PHP and the server file system _ php instance

This article mainly introduces the simple interaction between PHP and the server file system. it is very good and has reference value. if you are interested, let's take a look. 1. setting commands for file upload in php. ini

2. file upload process

(1) html code of the form for file upload and submission:

     
  Adminstration-upoload new files  Upload new files 

(2) php processes the uploaded file code

① In the php script, the data to be processed is stored in the Super variable array $ _ FILES. enabling the register_globals command can directly access this information through the variable name;

② If the form variable is named "username", there are:

$ _ FILES ['userfile'] ['tmp _ name']: the temporary storage location of the stored FILES on the Web server;
$ _ FILES ['userfile'] ['name']: stores the name of a file in the user's system;
$ _ FILES ['userfile'] ['size']: size of the stored file;
$ _ FILES ['userfile'] ['type']: type of the stored file;
$ _ FILES ['userfile'] ['error]: stores any error code related to file upload;

Error Type description:

UPLOAD_ERR_INI_SIZE: 1. the uploaded file exceeds the limit of the upload_max_filesize option in php. ini.
UPLOAD_ERR_FORM_SIZE: 2. the size of the uploaded file exceeds the value specified by the MAX_FILE_SIZE option in the HTML form.
UPLOAD_ERR_PARTIAL: 3. only part of the file is uploaded.
UPLOAD_ERR_NO_FILE: 4. no file is uploaded.
UPLOAD_ERR_NO_TMP_DIR: 6. the temporary folder cannot be found. PHP 4.3.10 and PHP 5.0.3 are introduced.
UPLOAD_ERR_CANT_WRITE: 7. file writing failed. PHP 5.1.0 is introduced.

③ Php code

<? Php // verify if ($ _ FILES ['userfile'] ['error']> 0) {echo 'problem '; switch ($ _ FILES ['userfile'] ['error']) {case 1: echo 'file exceeded upload_max_filesize '; break; case 2: echo 'file exceeded max_file_size '; break; case 3: echo 'file only partially upload'; break; case 4: echo 'No File uploaded'; break; case 6: echo 'cannot upload file: no temp directory specified '; break; case 7: echo 'upload failed: Cann Ot write to disk'; break;} exit;} // check whether the transmitted file is a text file if ($ _ FILES ['userfile'] ['type']! = 'Text/plain ') {echo 'problem: file is not plain text'; exit ;} // include the uploaded file in the/uploads/directory on the server (this directory must be independent of the Web document tree) $ upfile = '/uploads /'. $ _ FILES ['userfile'] ['name']; // create a new file if (is_uploaded_file ($ _ FILES ['userfile'] ['tmp _ name']) with the file name of the transfer file in the specified directory) {if (! Move_uploaded_file ($ _ FILES ['userfile'] ['tmp _ name'], $ upfile) {// Move the temporary file for transfer to the created file echo 'problem: cocould not move file to destination directory '; exit;} else {echo 'problem: Possible file upload attack. filename: '; echo $ _ FILES ['username'] ['name']; exit;} echo "File uploaded seuucessfully

"; // Mark html and php for the transfer file $ contents = file_get_contents ($ upfile); // extract the file content into a string; $ contents = strip_tags ($ contents ); // erase the html and tags of the string; file_put_contents ($ _ FILES ['userfile'] ['name'], $ contents ); // re-write the string to the file; // display the transmitted text file content in the browser echo"
Preview of uploaded file contents:
> "; Echo nl2br ($ contents); echo"
";

3. use directory functions

(1) read the file name from the Directory

① Use the opendir (), readdir (), closedir () functions;

<? Php $ current_dir = '/uploads/'; // Create a Directory url object $ dir = opendir ($ current_dir); // open the directory and return a directory object echo"
Upload directory is $ current_dir
"; Echo"
Directory Listing:
 
 

  
  
"; While ($ file = readdir ($ dir ))! = False) {// read the directory object if ($ file! = "." & $ File! = "..") {// Filter the current directory and the upper-level directory echo"
  
  
$ File
"; Echo" ". $ file ."
  
  
";}} Echo"
 
 
"; Closedir ($ dir); // Close the directory;?>

② Use php's dir class

<? Php $ current_dir = '/uploads/'; // Create a Directory url object $ dir = dir ($ current_dir); // create the dir object echo"
Handle is $ dir-> handle
"; Echo"
Upload directory is $ current_dir
"; Echo"
Directory Listing:
 
 

  
  
"; While ($ file = $ dir-> read ())! = False) {// read the file name in the directory through the dir object if ($ file! = "." & $ File! = "...") {Echo"
  
  
$ File
";}} Echo"
 
 
"; $ Dir-> close (); // close the directory?>

(2) use the scandir () function to sort text names alphabetically

<? Php $ current_dir = '/uploads/'; // Create a Directory url object $ files1 = scandir ($ current_dir); // Save the file name in the specified directory as an array, by default, $ files2 = scandir ($ current_dir, 1) is sorted in ascending alphabetical order. // Save the file names in the specified directory as an array and sort them in descending alphabetical order. echo"
Upload directory is $ current_dir
"; Echo"
Directory Listing in alphabetical order, ascending:
 
 

  
  
"; Foreach ($ files1 as $ file1) {if ($ file1! = "." & $ File1! = "...") Echo"
  
  
$ File1
";} Echo"
 
 
";?>

(3) obtain other information about the current directory

Dirname ($ path): returns the directory part of the path;

Basename ($ path): return the name of the path;

Disk_free_space ($ path): the disk where the returned path is located can store the size of uploaded files;

(4) create and delete directories

① Mkdir (): create a directory;

Code:

$ Oldumask = umask (0); // reset the current permission code mkdir ("/tmp/testing", 0777); // create the directory umask ($ oldumask ); // restore the current permission code

② Rmdir (): delete the directory;

Code:

Rmdir ("/temp/testing"); or rmdir ("c: \ tmp \ testing ');

※The directory to be deleted must be empty;

4. interaction with the file system

(1) Get file information:

While ($ file = readdir ($ dir ))! = False) {echo "". $ file ."
";}<? Php $ current_dir = '/uploads/'; $ file = basename ($ file); // Obtain the file name echo "Details of File"; echo "file data "; echo 'file last accessed :'. date ('j f y h: I ', fileatime ($ file ))."
"; // Return the recent access timestamp echo 'file last modifixed: '. date ('j f y h: I', filemtime ($ File ))."
"; // Return the last modified timestamp $ user = posix_getpwuid (fileowner ($ file); // return the uid echo 'file owner :'. $ user ['name']."
"; $ Group = posix_getgrgid (filegroup ($ file); // return the organization ID gid echo 'file group: '. $ group ['name']."
"; Echo 'file permissions: '. decoct (fileperms ($ File ))."
"; // Return the 8-bit permission code echo 'file type'. filetype ($ File )."
"; // Return the File type echo 'file size'. filesize ($ file )."
"; // Number of returned File bytes echo" File Tests "; echo 'is _ dir? '. (Is_dir ($ file )? 'True': 'false ')."
"; Echo 'is _ executable? '. (Is_executable ($ file )? 'True': 'false ')."
"; // Determine whether the file is executable; echo 'is _ file? '. (Is_file ($ file )? 'True': 'false ')."
"; Echo 'is _ link? '. (Is_link ($ file )? 'True': 'false ')."
"; Echo 'is _ readable? '. (Is_readable ($ file )? 'True': 'false ')."
"; Echo 'is _ writable? '. (Is_writable ($ file )? 'True': 'false ')."
";?>

(2) modifying file properties

Chgrp (file, group): modifies the file group;

Chmod (file, permissions): modify the object ACL;

Chown (file, user): modifies the object owner;

(3) creating, deleting, and moving files

Bool touch ($ filename, [int time, [int atime]): creates a file (time specifies the creation timestamp, and atime specifies the optional timestamp)

Unlink ($ filename): deletes an object.

Copy ($ source_path, $ destination_path): copy an object

Rename ($ oldfile, $ newfile): rename an object;

(4) use a program to execute functions

① String exec (String command [, array result [, int result_value])

Return the last row of the naming result. The result variable can return the number of character groups. these strings represent each row of the output. result_value gets the return code;

② Void passthru (String command [, int result_value])

The result is directly output to the browser;

③ String system (string command [, int return_value])

Output the result to the browser and return the last line or false of the command result;

※The data submitted by the user includes part of the command execution, which should be packaged as follows:

System (escapeshellcmd ($ command ));

5. interaction with environment variables

Phpinfo () function: obtains the list of all php variables;

Getenv ("$ key_name "):

Setenv ("$ key_name = $ value ");

The above is a simple interaction between PHP and the server file system introduced by Xiaobian. I hope it will help you. if you have any questions, please leave a message and I will reply to you in a timely manner. I would like to thank you for your support for the script home website!