File Access

Functions

  • $handle = fopen( FILENAME, FILEMODE ) 
FILEMODE:
    'r'   read       r 
    'r+'  write      r/w 
    'w'   overwrite    w 
    'w+'  overwrite  r/w 
    'a'   append       w 
    'a+'  append     r/w
  • For binary files, include 'b' in the file mode (i.e. "rb", "wb") (not needed in Unix, but helpful for portability).
  • $bool = fclose( $handle )
  • $str = fread( $handle, LENGTH )
  • $int = fwrite( $handle, $string [, LENGTH] )
  • Return value; FALSE: error; Else: number of bytes written.
  • $int = fseek( $handle, OFFSET [, RELATIVE_TO = SEEK_SET] )
  • RELATIVE_TO: SEEK_SET, SEEK_CUR, SEEK_END
  • Return value; 0: success, -1: failure.
  • $bool = feof( $handle )
  • $int = ftell( $handle )  // Get current file position.
  • $int rewind ( $handle )  // Return value; 1: success; 0: error.
  • $bool = ftruncate( $handle, LENGTH )
  • $array = file( FILENAME )  // Read an entire file. Binary-safe as of PHP 4.3.0.
  • $string = file_get_contents( FILENAME )  // Read an entire file. Binary-safe.
  • $int = file_put_contents( FILENAME, $string [, FILE_APPEND] )  // Write string to file. Binary-safe.
  • $string = fgetc( $handle)  // Read a single character. Returns FALSE on EOF.
  • $string = fgets( $handle [, LENGTH = 1024])  // Reads up to LENGTH - 1 characters.
  • Returns FALSE if error.
  • Stops reading at newline (included in return value) or EOF.
  • $array = fscanf( $handle, FORMAT_STR )
  • $num_vars = fscanf( $handle, FORMAT_STR [, $var]+ )
  • $filename = basename( $fullname [, $suffix_to_remove] )
  • $path = dirname( $fullname )
  • $path_array = pathinfo( $fullname )  // Array-element keys: "dirname", "basename", "extension"
  • $abs_fullname = realpath( $rel_fullname )
  • copy, mkdir, rename, rmdir, unlink (delete a file), symlink (create a symbolic link)
  • file_exists, is_dir, is_executable, is_file, is_link, is_readable, is_writable (aka "is_writeable")
  • filesize, filetype, disk_free_space

URL wrappers

  • Doesn't allow existing files to be overwritten.
  • If allow_url_fopen is enabled in php.ini, HTTP and FTP URLs can be used with most of the functions that take a filename as a parameter (as of PHP 4.0.4); prior to that, the following option had to be configured: -enable-url-fopen-wrapper.
  • You can also write to files on an FTP server (provided that you have connected as a user with the correct access rights). You can only create new files using this method; if you try to overwrite a file that already exists, the fopen() call will fail.
  • To connect as a user other than 'anonymous', you need to specify the username (and possibly password) within the URL, such as 'ftp://user:password@ftp.example.com/path/to/file'. (You can use the same sort of syntax to access files via HTTP when they require Basic authentication.)  
<?php 
$file = fopen ("ftp://ftp.example.com/incoming/outputfile", "w"); 
if (!$file) { 
    echo "<p>Unable to open remote file for writing.\n"; 
    exit; 
} 
// Write the data here. 
fputs ($file, $_SERVER['HTTP_USER_AGENT'] . "\n"); 
fclose ($file); 
?>