Common functions for php to read local files (fopen and file_get_contents)

In the following example, we use the .txt file as an example to introduce the function for php to read local files. to read files, we can use fopen or file_get_contents to read them. file_get_contents is simpler while fopen can display the read content only when fread is used.

1. first introduce the fopen () function

Below we provide a code demo for directly opening a local file. We have added comments to all the necessary parts:

Copy codeThe Code is as follows:
// Directly open the instance code of a local file
<? Php
// Assume that your file is a text file named xmlas.txt.
$ Filedemo = "xmlas.txt ";
$ Fpdemo = fopen ($ filedemo, "r ");
If ($ fpdemo ){
While (! Feof ($ fpdemo )){
// 1000 characters read
$ Datademo = fread ($ fpdemo, 1000 );
}
Fclose ($ fpdemo );
}
Echo $ datademo;
?>

2. Use the file_get_contents () function to output the entire file in a string:

Assume that the xmlas.txt text file has the following sentence: Nowadays, movies are getting less and less passionate. If you want to see all the climblies, please watch Japanese love.

Action movie!
The instance code of the file_get_contents () function is as follows:

Copy codeThe Code is as follows:
<? Php
Echo file_get_contents ("xmlas.txt ");
// The volume output content is in xmlas.txt:
// Today's movies are getting less and less passionate. If you want to see all the climax, please watch Japanese love action movies!
?>

3. How to read a local folder instead of a single file:
Please refer to the following instance code. In the instance, we will read a folder named xmlas:

Copy codeThe Code is as follows:
<? Php
$ Dirdemo = opendir ('/xmls ');
While ($ filedemo = readdir ($ dirdemo ))! = False ){
If ($ filedemo! = "." & $ Filedemo! = ".."){
$ Nsdemo = explode ('.', $ filedemo );
Echo $ nsdemo [0];
}
}
Closedir ($ dirdemo );
?>

4. We can also use fopen to write files.

Copy codeThe Code is as follows:
/**
* Use fopen to write files
* @ Param string $ filename
* @ Param string $ contents
* @ Return boolean
*/

Function wirte ($ filename, & $ contents)
{
$ Fp = fopen ($ filename, "wb ");
If ($ fp)
{
Flock ($ fp, LOCK_EX); // lock the file at the same time, only one person can operate
Fwrite ($ fp, $ contents );
Flock ($ fp, LOCK_UN); // Save the data grip to unlock the file and save it
Fclose ($ fp );
Return true;
} Else
{
Return false;
}
}

In this way, I can use fopen and fwrite to read and write files.

Note: l open the file

Before opening a file, we need to know the path of the file and whether the file exists.

Use the built-in global variables of $ _ SERVER ["DOCUMENT_ROOT"] to obtain the relative path of the site. As follows:

Copy codeThe Code is as follows: $ root = $ _ SERVER ["DOCUMENT_ROOT"];

Use the file_exists () function to check whether a file exists. As follows:

Copy codeThe Code is as follows:
If (! File_exists ("$ root/order.txt") {echo 'file does not exist ';}

This may be more reasonable and practical.