Summary of usage examples of functions for reading files in PHP

Recently sorted out several common ways to read files in PHP and paid attention to some codes, as follows:

You can use fopen and ## to read files in PHP #file_get_contentsThere is no essential difference between these two functions, except that the php code for reading files in the former is a little more complicated than the latter.

<?php
$file_name = "1.txt";
echo $file_name . "";
$fp = fopen($file_name, &#39;r&#39;);
//$buffer=fgets($fp);
while (!feof($fp)) {
$buffer = fgets($fp);
echo $buffer;
}
fclose($fp);
?>

1.fread

string fread ( int $handle , int $length )

<?php
 $filename = "/usr/local/something.txt";
 $handle = fopen($filename, "r");//读取二进制文件时，需要将第二个参数设置成&#39;rb&#39;
 
 //通过filesize获得文件大小，将整个文件一下子读到一个字符串中
 $contents = fread($handle, filesize ($filename));
 fclose($handle);
?>

remote file or a stream file, this method cannot be used, because filesize cannot obtain the size of these files. At this time, you need to use the return value of feof() or fread() to determine whether the end of the file has been read.

<?php
 $handle = fopen(&#39;http://www.baidu.com&#39;, &#39;r&#39;);
 $content = &#39;&#39;;
 while(!feof($handle)){
  $content .= fread($handle, 8080);
 }
 echo $content;
 fclose($handle);
?>

<?php
 $handle = fopen(&#39;http://www.baidu.com&#39;, &#39;r&#39;);
 $content = &#39;&#39;;
 while(false != ($a = fread($handle, 8080))){//返回false表示已经读取到文件末尾
  $content .= $a;
 }
 echo $content;
 fclose($handle);
?>

2.fgets

string fgets ( int $handle [, int $length ] )

<?php
 $handle = fopen(&#39;./file.txt&#39;, &#39;r&#39;);
 while(!feof($handle)){
  echo fgets($handle, 1024);
 }
 fclose($handle);
?>

3.fgetss

string fgetss ( resource $handle [, int $length [, string $allowable_tags ]] )

<?php
 $handle = fopen(&#39;./file.txt&#39;, &#39;r&#39;);
 while(!feof($handle)){
  echo fgetss($handle, 1024, &#39;<br>&#39;);
 }
 fclose($handle);
?>

4.file

array file ( string $filename [, int $use_include_path [, resource $context ]] )

<?php
 $a = file(&#39;./file.txt&#39;);
 foreach($a as $line => $content){
  echo &#39;line &#39;.($line + 1).&#39;:&#39;.$content;
 }
?>

5.readfile

Read a file and write it to the output buffer. Returns the number of bytes read from the file. If an error occurs, FALSE is returned and an

is displayed unless called as @readfile().

<?php
 $size = readfile(&#39;./file.txt&#39;);
 echo $size;
?>

file_get_contents##string file_get_contents ( string $filename [, bool $use_include_path [, resource $context [, int $offset [, int $maxlen ]]]] )

Read the file into a string. The third parameter $context can be used to set some parameters, such as setting timeout when accessing remote files, etc.

<?php 
 $ctx = stream_context_create(array( 
  &#39;http&#39; => array( 
   &#39;timeout&#39; => 1 //设置超时
   ) 
  ) 
 ); 
 echo file_get_contents("http://www.baidu.com/", 0, $ctx); 
?>

7.fpassthru

int fpassthru ( resource $handle )

Change the given file pointer from the current The position is read to EOF and the result is written to the output buffer.

<?php 
 header("Content-Type:text/html;charset=utf-8"); 
 $handle = fopen(&#39;./test2.php&#39;, &#39;r&#39;);
 fseek($handle, 1024);//将指针定位到1024字节处
 fpassthru($handle);
?>

8.parse_ini_file

##array parse_ini_file ( string $filename [, bool $process_sections ] )

parse_ini_file() loads an ini file specified by filename and returns its settings as an associative array. If you set the final process_sections parameter to TRUE, you will get a multidimensional array, including the name and settings of each section in the

. The default value for process_sections is FALSE. Notice:

1. If the value in the ini file contains any non-alphanumeric characters, it needs to be enclosed in double quotes (").
2. Some reserved words cannot be used as key names in the ini file, including: null, yes, no, true and false. The values ​​null, no and false are equivalent to "", and the values ​​yes and true are equivalent to "1". The characters {}|&~![()" cannot be used either. anywhere in the key name, and these characters have special meaning in the option value.

A few Notes:

1. It is encouraged to use the b flag when processing binary files, even if the system does not require it, this can make the script more portable .

2. The allow_url_fopen option activates the URL form of the fopen encapsulation protocol so that URL objects such as files can be accessed. The default encapsulation protocol provides access to remote files using the ftp and http protocols. Some extension libraries such as zlib may register more encapsulation protocols. For security reasons, this option can only be set in php.ini.

3. If you want to open a URL with special characters (for example, spaces), you need to use urlencode() for URL encoding.

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