PHP Programming 8 common file operations in website construction

  File and directory actions  

PHP is convenient for processing files and directories on the local server, but sometimes permissions and path-related problems  

1. Open File  

Resource fopen (string filename , string mode [, bool Use_include_path [, Resource Zcontext]])  

$handle = fopen (filename,mode)//Open file, returned to represent this article The

file name can use a relative path or an absolute path or network protocol mode, and the open mode has rr+ww+aa+xx+b 

If you do not specify a ' B ' mark when manipulating a binary file, the &NBSP There may be some strange problems, including bad picture files and strange questions about RN characters. &NBSP

For portability considerations, it is strongly recommended that you always use the ' B ' flag when opening a file with fopen (). &NBSP

The following are several ways to open a file  

$fp = @fopen (' Log.txt ', ' RB ');  

$fp = @fopen ('. /log.txt ', "RB");  

$fp = @fopen ("http://www.runer.com.cn/default.htm", "RB");//You can also use protocols such as FTP and Ghoper. You must enable the Allow_url_fopen option   in the php.ini file;

////////////////////////////Code Section//////////////////////////////// &NBSP

$filename 1 = "Userinfo.txt"; the file exists in the directory or include_path  

$filename 2 = "test.txt"; /directory or include_path does not exist this file  

$resource 1 = fopen ($filename 1, "RB")  

@ $resource 2 = FOPEn ($filename 2, "RB");//Because this file does not exist in the directory and is not used or include_path to find the path where the containing file is located, this action will complain, and using the error suppressor @ can force the browser not to output the error message  

If ($resource 1)  

echo "Open file {$filename 1} succeeded";  

if (! @fopen ($filename 2, "R"))  

Echo "Open File {$filename 2} is unsuccessful";  

////////////////////////////////////////////////////////////////////////// &NBSP

---------------------output---------------------------------------- 

Open File Userinfo.txt successful  

--------------------------------------------------------------------- 

2. After using the file, you should explicitly tell PHP that you have finished using the file, and let the operating system ensure that all contents of the file are flushed correctly from the buffer to the hard drive  

Use fclose () to close the file,  

BOOL Fclose (resource handle)//closes an open file pointer

3. Read the file, the mode parameter of the fopen function allows reading, PHP provides several functions to read data from the file  

string fgets (int handle [, int length]) reads a row from the file pointer, Trying fgets on a binary file produces unpredictable results  

If you do not specify a length, the default reads 1K data, stops the   when it encounters a newline character (including in the return value), EOF, or has read the length-1 byte;

String FGETSS (resource handle [, int length [, string allowable_tags]]) reads a row from the file pointer and filters out  HTML  tag  

FGETC () reads a single character  

Fread () reads arbitrary binary data  

////////////////////////////Code Section///////////////////// &NBSP

$handle = fopen ("Test.jpg", "RB"),  

$c;  

while!feof ($ha Ndle)) { 

$contents. = @fread ($handle, 8192);//loop Read and merge it into a large file  

} 

Fclose ($ handle);  

////////////////////////////////////////////////////////////////////////// 

---------------------output---------------------------------------- 

------------------------------- -------------------------------------- 

4. Determine the state of the file read &nbSp

Each file handle has a file pointer, or a cursor that indicates where the next operation will occur in the file, depending on the mode parameter of the fopen function   the

file pointer is initially at the beginning of the file (0), or at the end of the file   The

feof () can determine whether the file is at the end (the function returns true after the end)   the

FileSize () function returns the size of the file 5. write file  

fwrite () function performs file write &NBSP

////////////////////////////Code part//////////////////////////////////////// 

$filename = ' Test.txt ';  

$somec;

 

//First we want to make sure that the file exists and is writable. &NBSP

if (is_writable ($filename)) { 

//In this example, we will use Add mode to open the $filename, 

//Therefore, The file pointer will be at the beginning of the file,  

, or that is where we $somecontent will write when we use Fwrite (). &NBSP

if (! $handle = fopen ($filename, ' a ')) { 

echo "Cannot open file $filename";  

exit; 

} 

//writes $somecontent to the file we open. &NBSP

if (fwrite ($handle, $somecontent) = = FALSE) { 

echo "cannot be written to the file $filename";  

Exi T;&NBSP

} 

Echo successfully writes the $somecontent to the file $filename ";  

Fclose ($handle);  
br>} else { 

} 

echo "file $filename not writable";  

///////////////////////////////////// &NBSP

--------------------- The output---------------------------------------- 

Successfully writes the added text to the file test.txt 

------------ --------------------------------------------------------- 

for binary data, you must specify a third parameter that contains the number of data bytes written to disk  

$result = @fwrite ($fp, $binary _data,mb_strlen ($binary _data, ' 8bit ');

 

&N BSP; 6. File permissions and other information   Is_readable ()/To determine whether the file is readable   Is_ Writeable ()//To determine whether the file can be written   is_writable ()//To determine whether the file is writable   Fileperms ()//Determine file Permissions (Unix-style file permissions test function) &NBSP File_exists ()/whether there is a file   Fileowner ()//To determine the user to which the file belongs   Filegroup ()/To determine the group to which the file belongs &NBSP 7. Delete and rename the file   Unlink ()//delete file   Rename ()/rename file   8. Access Directory   Directory Access recommends the use of forward slash "/", compatible with Windows and UNIX systems   basename ()//returns a filename that does not include path information   DirName ()// Returns the directory portion of the file name   Realpath ()/Accept the relative path, returning the absolute path   the file, PathInfo ()//fetching the directory name of the given path, the base file name and the extension   Opendir ()//Open Directory, return resource handle   Readdir ()/Read directory entry   Rewinddir ()//Returns the read pointer to the beginning &NBSP Closedir ()//closes the read handle   ChDir ()//changing the current working directory during the current script execution   mkdir ()//Create directory   rmdir () delete directory   ////////////////////////////Code Section////////////////// &NBSP ////////////////////////////////////////////////////////////////////////// &NBSP ---------------------output----------------------------------------  filename:  WEB&NBSP: filetype:dir  Filename:study:filetype:dir Reproduced in www.abm163.com