php ip query region

With the rapid development of the Internet, more and more websites and applications need to implement the function of IP address query region. IP address query area can provide users with more accurate services and provide more refined data support for businesses.

It is relatively simple to implement the function of IP address query region in PHP language. This article will introduce the principles and methods of implementing IP address query in PHP, and help readers understand how to implement the IP address region query function in their own websites and applications.

1. IP address query principle

The principle of IP address query region is to convert the IP address into the corresponding decimal value, and obtain the corresponding region by querying the pre-prepared IP address library information. The IP address database usually contains the range of IP addresses and corresponding regional information, such as country, city, etc.

2. Convert IP address to decimal value

The IP address is composed of four 8-bit binary numbers, and the value range of each array is 0~255. IP addresses can be converted into decimal values. The specific conversion method is as follows:

Shift the first array to the left by 24 bits, shift the second array to the left by 16 bits, shift the third array to the left by 8 bits, leave the fourth array unchanged, and shift the four arrays to the left Perform a bitwise OR operation to get the decimal value corresponding to the IP address.

For example, if the IP address is 192.168.0.1, the process of converting it into a decimal value is as follows:

192 << 24 = 3232235520

168 << 16 = 1107296256

0 << 8 = 0

1 = 1

3232235520 | 1107296256 | 0 | 1 = 3232235521

3. Preparation IP address library

In order to realize the function of IP address query area, an IP address library needs to be prepared. This library can be downloaded or purchased from some public websites or data providers.

The IP address database format is generally a text file, and each line stores an IP address segment and corresponding region information. For example, the following is an example of an IP address library file:

125.78.0.0-125.79.255.255 Shanghai, China

125.103.0.0-125.103.127.255 Zhejiang, China

125.110.0.0 -125.110.3.255 Guangdong, China

The IP address database can be stored and managed using a MySQL database. Specifically, the decimal values ​​of the starting and ending values ​​of the IP address segment are stored in a table and indexed to improve Query efficiency.

4. PHP implements the IP address query region function

To implement the IP address query region function in PHP language, the following steps are required:

1. Obtain the user's IP address

In PHP language, you can use the $_SERVER['REMOTE_ADDR'] global variable to obtain the user's IP address. This variable stores the user's IP address, for example:

$user_ip = $_SERVER['REMOTE_ADDR'];

2. Convert the IP address into the corresponding decimal value

Use PHP's ip2long() function to convert the IP address into the corresponding decimal value, for example:

$ip_long = ip2long($user_ip);

3. Query the region corresponding to the IP address Information

Each row in the IP address database stores an IP address segment and corresponding region information. Therefore, it is necessary to arrange the IP address library files according to "IP address from small to large" and use a binary search algorithm to query whether the user's IP address is in the IP address library. If it exists, return the corresponding region information.

The specific implementation code is as follows:

function query_region_by_ip($ip_long, $ip_file) {
$region = 'Unknown';
$fp = fopen($ip_file, 'rb');
if (!$fp) {

return $region;

}
fseek($fp, 0, SEEK_SET);
$line_size = 24;
$begin = 0;
$end = filesize($ip_file) / $line_size - 1;
while ($begin <= $end) {

$middle = intval(($begin + $end) / 2);
fseek($fp, $middle * $line_size, SEEK_SET);
$line = fread($fp, $line_size);
$start_ip = unpack('N', substr($line, 0, 4))[1];
$end_ip = unpack('N', substr($line, 4, 4))[1];
if ($ip_long < $start_ip) {
  $end = $middle - 1;
}
elseif ($ip_long > $end_ip) {
  $begin = $middle + 1;
}
else {
  $off = unpack('V', substr($line, 8, 2) . "\x0\x0")[1];
  fseek($fp, $off, SEEK_SET);
  $region = rtrim(fread($fp, $line_size - 8));
  break;
}

}
 fclose($fp); 
 return $region;
}
5. Summary
IP address query region is one of the common needs of websites and applications. Implementing the function of IP address query region can provide users with more personalized services and improve user satisfaction and user stickiness. 
This article introduces the principles and methods of implementing IP address query region in PHP, including the detailed process of converting IP addresses into corresponding decimal values, preparing IP address libraries, and using PHP programs to implement the IP address query region function. Readers can adjust and optimize according to their own needs and actual conditions. 
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