is_file()

(PHP 4, PHP 5, PHP 7)

判断给定文件名是否为一个正常的文件

说明

判断给定文件名是否为一个正常的文件。

参数

文件的路径。

返回值

如果文件存在且为正常的文件则返回TRUE，否则返回FALSE。

Note:因为 PHP 的整数类型是有符号整型而且很多平台使用 32 位整型，对 2GB以上的文件，一些文件系统函数可能返回无法预期的结果。

范例

Example #1is_file()例子

以上例程会输出：

bool(true)
bool(false)

错误／异常

失败时抛出E_WARNING警告。

注释

Note:此函数的结果会被缓存。参见clearstatcache()以获得更多细节。

自 PHP 5.0.0 起,此函数也用于某些URL 包装器。请参见支持的协议和封装协议以获得支持stat()系列函数功能的包装器列表。

参见

• is_dir() 判断给定文件名是否是一个目录
• is_link() 判断给定文件名是否为一个符号连接

Note that is_file() returns false if the parent directory doesn't have +x set for you; this make sense, but other functions such as readdir() don't seem to have this limitation. The end result is that you can loop through a directory's files but is_file() will always fail.

if you're running apache as a service on a win32 machine, an you try to determinate if a file on an other pc in your network exists - ex.: is_file('//servername/share/dir1/dir2/file.txt') - you may return false when you're running the service as LocalSystem. To avoid this, you have to start the Apache-Service as a 'registered' domain user.

I tend to use alot of includes, and I found that the is_file is based on the script executed, not ran.
if you request /foo.php and foo.php looks like this:

and bar.php looks like this:

Then PHP (on win32, php 5.x) would look for /foo/bar.txt and not /foobar/foo/bar.txt.
you would have to rewrite the is_file statement for that, or change working directory.
Noting this since I sat with the problem for some time,
cheers, Toxik.

sometimes this function does not work because permission , 
you can use this function that check if the path has dot in last will return true . 
public function isFile($file) {
    $f = pathinfo($file, PATHINFO_EXTENSION);
    return (strlen($f) > 0) ? true : false;
  }
 
isfile('http://www.ip4t.net/image.jpg');
you should replace a string between '' with your file path to check

regarding note from rehfeld dot us : 
In my experience the best( and easiest ) way to find the extension of a file is : 

or 

It took me a day or so to figure out that is_file() actually looks for a valid $ existing path/file in string form. It is not performing a pattern-like test on the parameter given. Its testing to see if the given parameter leads to a specific existing 'name.ext' or other (non-directory) file type object.

### Symbolic links are resolved ###
If you pass a symlink (unix symbolic link) as parameter, is_file will resolve the symlink and will give information about the refered file. For example:
 touch file
 ln -s file link
 echo '' | php -q
will print "y".
is_dir resolves symlinks too.

In PHP 4.1.0 under win32, this seems to print out a warning message if the file does not exist (using error_reporting = E_ALL & ~E_NOTICE).

here is a workaround for the file size limit. uses bash file testing operator, so it may be changed to test directories etc. (see http://tldp.org/LDP/abs/html/fto.html for possible test operators)

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