The difference between fwrite and file_put_contents in PHP

In PHP, fwrite and file_put_contents are different in details, but file_put_contents is more powerful in terms of performance. Let's compare it with an example below.

Similar points: The file_put_contents() function writes a string to a file, which has the same function as calling fopen(), fwrite() and fclose() in sequence.

Difference: Using FILE_APPEND in the file_put_contents() function can avoid deleting the existing content in the file, that is, realizing the append function when writing the same file multiple times.

For example:

echo file_put_contents("test.txt","Hello World. Testing!",FILE_APPEND);

file_put_contents writes the string into test.txt in the form of append,

fwrtie will clear the previous records and only retain the currently written content

$file = fopen("test.txt","w");
echo fwrite($file,"Hello World. Testing!");
fclose($file);

file_put_contents has many advantages instead of fwrite

The following is the example code of file_put_contents:

$filename = 'file.txt';
$word = "Hello!rnwebkaka"; //Double quotation marks will wrap, single quotation marks will not wrap
file_put_contents($filename, $word);
?>

Example code for using fwrite for the same function:

$filename = 'file.txt';
$word = "Hello!rnwebkaka"; //Double quotes will wrap, single quotes will not wrap
$fh = fopen($filename, "w"); //w is written from the beginning and a is appended and written
echo fwrite($fh, $word);
fclose($fh);
?>

As can be seen from the above two examples, file_put_contents is actually a simplified writing method of fopen, fwrite, and fclose. This is beneficial to the optimization of program code. On the one hand, the amount of code is reduced, on the other hand There will be no loose code missed by fclose, which makes debugging and maintenance much easier.

In the above example, file_put_contents is written from the beginning. What should I do if I want to write additionally?

In the syntax of file_put_contents, there is a parameter FILE_APPEND, which is a statement for additional writing. The example code is as follows:

echo file_put_contents('file.txt', "This is another something.", FILE_APPEND);
?>

FILE_APPEND is a statement for append writing. When appending to write, in order to avoid other people operating at the same time, it is often necessary to lock the file. In this case, you need to add an additional LOCK_EX statement, which is written as follows:

echo file_put_contents('file.txt', "This is another something.", FILE_APPEND|LOCK_EX);
?>

Note that in the above code, what echo outputs to the display is the length of the string written to the file.

FAQ:

Warning: fopen(file.txt) [function.fopen]: failed to open stream: Permission denied

When writing to a file, you sometimes encounter the above problem. This is because the file does not have write permissions. In order to avoid this error, you need to determine whether the file is writable when writing a file. This requires the use of the is_writable() function. The example code is as follows:

$filename = 'file.txt';
if (is_writable($filename)) {
echo file_put_contents($filename, "This is another something.", FILE_APPEND);
} else {
echo "The file $filename is not writable";
}
?>

fwrite simply writes the data into the handler
file_put_contents may need to process contentxt, the data type is mixed, more processing is needed
Although looking at the function description of file_put_contents: it has the same function as calling fopen(), fwrite() and fclose() in sequence.
But there must be subtle differences, especially when writing a large amount of data repeatedly, file_put_contents will undoubtedly repeat fopen and fclose. And fwrite can only fopen and fwrite once

Write a simple program to test, a 250M file

Conclusion: Multiple execution results show that the fopen, fwrite, and fclose methods are faster than direct file_put_contents!

So why? View source code

I use ubuntu12.04
Directly sudo apt-get source php5
Unzip:silver@silver-desktop:~/php/php5-5.3.3

Find the function fwrite function: silver@silver-desktop:~/php/php5-5.3.3$ grep -rn “PHP_FUNCTION(fwrite)” .
./ext/standard/file.c:1233:PHPAPI PHP_FUNCTION(fwrite)
./ext/standard/file.h:43:PHPAPI PHP_FUNCTION(fwrite);

fwrite

Find the corresponding source code. The function is very simple:

file_put_contents
This function has many more processing operations

什么时候用fwrite,file_put_contents ?

1，函数原型已经说明了它们处理的数据类型不一样
2，简单的文件处理，追求速度用fwrite
3，书写简单用file_put_contents – (啥类型的数据都能处理，magic阿。但是要理解类型判断机制，否则保存的数据可能不是你想要的）