PHP implementation code to determine whether a remote image or file exists_PHP tutorial

The easiest way is to use fopen() to see if the file can be opened. If it can be opened, the file will of course exist

Copy the code The code is as follows:

$url = 'http://www.jb51.net/images/test.jpg';

if( @fopen( $url, 'r' ) )
{
echo 'File Exits';
}
else
{
echo 'File Do Not Exits ';
}
?>

Syntax: fopen(filename,mode,include_path,context)

参数	描述
filename	必需。规定要打开的文件或 URL。
mode	必需。规定要求到该文件/流的访问类型。可能的值见下表。
include_path	可选。如果也需要在 include_path 中检索文件的话，可以将该参数设为 1 或 TRUE。
context	可选。规定文件句柄的环境。Context 是可以修改流的行为的一套选项。

Possible values ​​for the mode parameter

mode

Description

"r"

Open in read-only mode and point the file pointer to the file header.

"r+"

Open in read-write mode and point the file pointer to the file header.

"w"

Open writing mode, point the file pointer to the file header and truncate the file size to zero. If the file does not exist, try to create it.

"w+"

Open in read-write mode, point the file pointer to the file header and truncate the file size to zero. If the file does not exist, try to create it.

"a"

Open in writing mode and point the file pointer to the end of the file. If the file does not exist, try to create it.

"a+"

Open in read-write mode and point the file pointer to the end of the file. If the file does not exist, try to create it.

"x"

mode	说明
"r"	只读方式打开，将文件指针指向文件头。
"r+"	读写方式打开，将文件指针指向文件头。
"w"	写入方式打开，将文件指针指向文件头并将文件大小截为零。如果文件不存在则尝试创建之。
"w+"	读写方式打开，将文件指针指向文件头并将文件大小截为零。如果文件不存在则尝试创建之。
"a"	写入方式打开，将文件指针指向文件末尾。如果文件不存在则尝试创建之。
"a+"	读写方式打开，将文件指针指向文件末尾。如果文件不存在则尝试创建之。
"x"	创建并以写入方式打开，将文件指针指向文件头。如果文件已存在，则 fopen() 调用失败并返回 FALSE，并生成一条 E_WARNING 级别的错误信息。如果文件不存在则尝试创建之。 这和给底层的 open(2) 系统调用指定 O_EXCL|O_CREAT 标记是等价的。 此选项被 PHP 4.3.2 以及以后的版本所支持，仅能用于本地文件。
"x+"	创建并以读写方式打开，将文件指针指向文件头。如果文件已存在，则 fopen() 调用失败并返回 FALSE，并生成一条 E_WARNING 级别的错误信息。如果文件不存在则尝试创建之。 这和给底层的 open(2) 系统调用指定 O_EXCL|O_CREAT 标记是等价的。 此选项被 PHP 4.3.2 以及以后的版本所支持，仅能用于本地文件

Create and open for writing, pointing the file pointer to the file header. If the file already exists, the fopen() call fails and returns FALSE and generates an E_WARNING level error message. If the file does not exist, try to create it. This is equivalent to specifying the O_EXCL|O_CREAT flag to the underlying open(2) system call.

This option is supported by PHP 4.3.2 and later versions and can only be used for local files.

"x+"

Create and open for reading and writing, pointing the file pointer to the file header. If the file already exists, the fopen() call fails and returns FALSE and generates an E_WARNING level error message. If the file does not exist, try to create it. This is equivalent to specifying the O_EXCL|O_CREAT flag to the underlying open(2) system call. This option is supported by PHP 4.3.2 and later versions and can only be used for local files

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http: //www.bkjia.com/PHPjc/825288.htmlTechArticleThe easiest way is to use fopen() to see if the file can be opened. If it can be opened, the file will of course exist. Copy the code as follows: ?php $url = 'http://www.jb51.net/images/test.jpg'; if( @fo...