How to use PHP to develop a simple IP address query function

How to use PHP to develop a simple IP address query function

In the network, the IP address is a numerical address that uniquely identifies a device. Sometimes we need to obtain relevant information about an IP address, such as its geographical location, ISP provider, etc. In this article, we will use PHP to develop a simple IP address query function.

To implement this function, you need to use the third-party IP address query service API, and obtain the relevant information of the IP address by sending an HTTP request to the API. Below are specific steps and code examples.

Step 1: Get the IP address

First, we need to get the user’s IP address. In PHP, the user's IP address can be obtained through $_SERVER['REMOTE_ADDR']. The code example is as follows:

$ip = $_SERVER['REMOTE_ADDR'];

Step 2: Send HTTP request

Next, we need to send an HTTP request to the IP address query service API and pass the user's IP address as a parameter. Here we are using a free IP address query service API, which can be replaced by other services in the code. The code example is as follows:

$url = "http://api.ipapi.com/".$ip."?access_key=YOUR_ACCESS_KEY";
$response = file_get_contents($url);
$data = json_decode($response, true);

Note that you need to replace YOUR_ACCESS_KEY with your own API access key.

Step 3: Parse the API response

The API response is a JSON string containing information related to the IP address. We use PHP's json_decode function to parse it into an associative array for subsequent use. The code example is as follows:

$country = $data['country_name'];
$region = $data['region_name'];
$city = $data['city'];
$isp = $data['isp'];

Step 4: Display the results

Finally, we display the obtained IP address related information on the web page so that users can view it intuitively. The code example is as follows:

echo "IP地址：" . $ip . "<br>";
echo "所在国家：" . $country . "<br>";
echo "所在地区：" . $region . "<br>";
echo "所在城市：" . $city . "<br>";
echo "ISP供应商：" . $isp . "<br>";

The complete code example is as follows:

$ip = $_SERVER['REMOTE_ADDR'];
$url = "http://api.ipapi.com/".$ip."?access_key=YOUR_ACCESS_KEY";
$response = file_get_contents($url);
$data = json_decode($response, true);

$country = $data['country_name'];
$region = $data['region_name'];
$city = $data['city'];
$isp = $data['isp'];

echo "IP地址：" . $ip . "<br>";
echo "所在国家：" . $country . "<br>";
echo "所在地区：" . $region . "<br>";
echo "所在城市：" . $city . "<br>";
echo "ISP供应商：" . $isp . "<br>";

Through the above steps, we can implement a simple IP address query function. When a user accesses a web page, information related to his or her IP address is automatically obtained and displayed.

It should be noted that this example uses the free IP address query service API, which has daily query limits and access rate limits. If you need higher query frequency or more functions, you can consider using a paid IP address query service or building your own IP address database.

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