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English
In many API interfaces, especially services involving OAuth signatures, logging systems, or cross-time zone operations, it is often required that the client sends time in UTC (Coordinated World Time) format. By default, using the date() function will return time according to the server's local time zone, which may cause inaccurate timestamps if the time zone configuration is inconsistent.
The gmdate() function always returns GMT/UTC time regardless of the server configuration. Therefore, gmdate() is a more reliable option when you need to make sure that time is the standard UTC time.
Let's take a look at a typical example: when calling an API that requires a timestamp parameter, the parameter must be in the RFC 1123 format (for example , Wed, 23 May 2025 12:34:56 GMT ). This is a common time format in HTTP headers, such as for the Date field.
<?php
// current UTC time，conform to HTTP Header of Date Format
$date = gmdate('D, d M Y H:i:s') . ' GMT';
// 打印生成oftime
echo $date;
// Example：Used in one API 请求of Header middle
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "https://gitbox.net/api/example");
curl_setopt($ch, CURLOPT_HTTPHEADER, [
'Date: ' . $date,
'Authorization: Bearer YOUR_ACCESS_TOKEN'
]);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);
echo $response;
?>
In the above code, we use gmdate() to get the API-compliant time format and add it to the request header. This avoids verification failure or request rejection due to time zone issues.
Another common scenario is to use timestamps as part of the signature mechanism, for example when we need to send a signed request, the timestamp may be a variable in the signature string. At this time, the format we commonly use is UNIX timestamp, that is, the number of seconds from 00:00:00 UTC on January 1, 1970 to the current time.
<?php
// 获取current UTC time戳
$timestamp = time();
// use gmdate 验证输出of日期
$formatted = gmdate('Y-m-d\TH:i:s\Z', $timestamp);
echo "time戳：$timestamp\n";
echo "Format化time：$formatted\n";
// Example：Signature string
$secret = "your_secret";
$signature_base = "timestamp=$timestamp";
$signature = hash_hmac('sha256', $signature_base, $secret);
echo "sign：$signature\n";
?>
gmdate() provides a human-readable UTC time representation here, while time() provides a machine-processable raw timestamp. Both can be used flexibly as needed.
Ensuring that using UTC time is a basic but critical task when handling time-related API requests. PHP's gmdate() function provides a simple and direct way to generate standardized time strings. Whether used for HTTP headers, signature mechanisms or logging, the rational use of gmdate() can greatly improve the stability and security of interface interaction.
By combining gmdate() and time() , developers can meet the dual needs of human readability and system compatibility at the same time, thereby building more robust API client logic.
