Operation of files and directories
PHP is very handy for processing files and directories on the local server, but sometimes permissions and path-related issues can occur
1. Open File
Resource fopen (string filename, string mode [, bool Use_include_path [, Resource Zcontext]])
$handle = fopen (filename,mode)//Open file, return a handle to the resource representing this file
The file name can either use a relative path or an absolute path or you can use the network Protocol mode, and open mode has r\r+\w\w+\a\a+\x\x+\b
If you do not specify a ' B ' tag when working with binaries, you may encounter some strange problems, including broken picture files and strange questions about \ r \ n characters.
For portability, it is strongly recommended that you always use the ' B ' tag when opening a file with fopen ().
Here are a few ways to open files
$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////////////////////////////////////////
$filename 1 = "userinfo.txt";//the file exists in the directory or include_path
$filename 2 = "test.txt";//directory or include_path does not exist for this file
$resource 1 = fopen ($filename 1, "RB");
@ $resource 2 = fopen ($filename 2, "RB");//Because this file does not exist in the directory and does not use or include_path to find the path containing the file, this operation will error, using the error suppressor @ can force the browser not to output error messages
if ($resource 1)
echo "Open file {$filename 1} succeeded";
if (! @fopen ($filename 2, "R"))
echo "Open file {$filename 2} unsuccessful";
//////////////////////////////////////////////////////////////////////////
---------------------The result of the 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 the contents of the file are flushed correctly from the buffer to the hard disk
Use Fclose () to close the file,
BOOL Fclose (resource handle)//close an open file pointer
3. Read the file, the fopen function of the mode parameter 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 and attempts to fgets on the binary produce unpredictable results
If you do not specify a length, the default reads 1K data, encounters a newline character (included in the return value), EOF, or has read the length-1 byte and stops
String FGETSS (resource handle [, int length [, string allowable_tags]]) reads a row from the file pointer and filters out HTML tags
FGETC () reads a single character
Fread () reads any binary data
Code section////////////////////////////////////////
$handle = fopen ("Test.jpg", "RB");
$c;
while (!feof ($handle)) {
$contents. = @fread ($handle, 8192);//loop Read and merge it into a large file
}
Fclose ($handle);
//////////////////////////////////////////////////////////////////////////
---------------------The result of the output----------------------------------------
---------------------------------------------------------------------
4. Determine the status of the file read
Each file handle has a file pointer, or a cursor that indicates where the next operation will occur in the file, according to the mode parameter of the fopen function
The file pointer is initially located at the beginning of the file (0) or at the end of the file
Feof () can tell if the file has reached the end (the function returns true after the end)
The FileSize () function returns the size of the file 5. Writing files
Fwrite () function performs file write
Code section////////////////////////////////////////
$filename = ' test.txt ';
$somec;
First we want to make sure that the file exists and is writable.
if (is_writable ($filename)) {
In this example, we will use the Add mode to open the $filename,
Therefore, the file pointer will be at the beginning of the file,
That is where $somecontent will write when we use Fwrite ().
if (! $handle = fopen ($filename, ' a ')) {
echo "Cannot open file $filename";
Exit
}
Write the $somecontent to the file we opened.
if (fwrite ($handle, $somecontent) = = = = FALSE) {
echo "Cannot write to file $filename";
Exit
}
echo "successfully wrote $somecontent to file $filename";
Fclose ($handle);
} else {
}
echo "File $filename not writable";
//////////////////////////////////////////////////////////////////////////
---------------------The result of the output----------------------------------------
Successfully add these words to the file to be written 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 '));
6. File permissions and other information
Is_readable ()//Determine if the file is readable
Is_writeable ()//Determine if the file is writable
Is_writable ()//Determine if the file is writable
Fileperms ()//Determine file Permissions (Unix-style file permissions test function)
File_exists ()//whether this file exists
Fileowner ()//determine who the file belongs to
Filegroup ()//determine which group the file belongs to
7. Delete and rename files
Unlink ()//delete files
Rename ()//rename file
8. Accessing the Directory
Directory access recommends using forward slash "/" compatible with Windows and UNIX systems
BaseName ()//Returns a file name that does not include path information
DirName ()//Returns the directory portion of the file name
Realpath ()//Accept relative path, return absolute path of file
PathInfo ()//extract directory name, base file name and extension for the given path
Opendir ()//Open Directory, return resource handle
Readdir ()//Read directory entry
Rewinddir ()//will read the pointer back to the beginning
Closedir ()//close Read handle
ChDir ()//change the current working directory during the current script execution
mkdir ()//Create Directory
RmDir () Delete directory
Code section////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
---------------------The result of the output----------------------------------------
Filename:web:filetype:dir
Filename:study:filetype:dir
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