如何用fopen()和fwrite()将用户登录数据转为JSON数组带换行写入文件？

Got it, let’s break down exactly how to capture your user’s login details, structure them into a JSON array, and write that data to a file with proper line breaks using PHP’s fopen() and fwrite().

Step 1: Capture All Required Login Data #

First, let’s make sure we’re collecting all the fields you mentioned (user-agent, IP, timestamp, OS, etc.). We’ll also add a helper function to parse the operating system from the user agent string:

// Collect core login data
$loginEntry = [
    'user_id' => $userRow['user_id'],
    'login_timestamp' => $date->getTimestamp(), // Assumes $date is a valid DateTime object
    'login_ip' => $_SERVER['REMOTE_ADDR'],
    'user_agent' => $_SERVER['HTTP_USER_AGENT'],
    'operating_system' => getOperatingSystem($_SERVER['HTTP_USER_AGENT'])
];

// Helper function to detect OS from user agent
function getOperatingSystem($userAgent) {
    $osMatches = [
        '/windows nt 10/i'      => 'Windows 10',
        '/windows nt 6.3/i'     => 'Windows 8.1',
        '/windows nt 6.2/i'     => 'Windows 8',
        '/windows nt 6.1/i'     => 'Windows 7',
        '/macintosh|mac os x/i' => 'macOS',
        '/linux/i'              => 'Linux',
        '/ubuntu/i'             => 'Ubuntu',
        '/android/i'            => 'Android',
        '/iphone/i'             => 'iOS (iPhone)',
        '/ipad/i'               => 'iOS (iPad)',
        '/blackberry/i'         => 'BlackBerry',
        '/webos/i'              => 'WebOS'
    ];

    foreach ($osMatches as $regex => $osName) {
        if (preg_match($regex, $userAgent)) {
            return $osName;
        }
    }
    return 'Unknown OS';
}

Step 2: Handle the JSON File (Create or Update) #

Next, we need to either create a new JSON file (if it doesn’t exist) or update the existing one by adding our new login entry to the array. Here’s how to do that with fopen() and fwrite():

// Define your user folder and login file path
$userFolder = $_SERVER['DOCUMENT_ROOT'] . '/account/users/' . $auth_user->user_folder_name($userRow["user_id"], $userRow["username"]) . '/';
$loginFile = $userFolder . $userRow['username'] . '_login_history.json';

// Initialize the login array
$loginHistory = [];

// If the file exists, read and parse its current content
if (file_exists($loginFile)) {
    $existingContent = file_get_contents($loginFile);
    $loginHistory = json_decode($existingContent, true);
    
    // Fallback to empty array if JSON parsing fails
    if (!is_array($loginHistory)) {
        $loginHistory = [];
    }
}

// Add the new login entry to the array
$loginHistory[] = $loginEntry;

// Convert the array to formatted JSON (with line breaks and indentation)
$formattedJson = json_encode($loginHistory, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);

// Write the JSON to the file using fopen() and fwrite()
$fileHandle = fopen($loginFile, 'w');
if ($fileHandle) {
    // Write the JSON content plus a trailing newline for cleanliness
    fwrite($fileHandle, $formattedJson . PHP_EOL);
    fclose($fileHandle);
    // Optional: Confirm success
    // echo "Login history updated successfully!";
} else {
    // Handle error if file can't be opened
    // echo "Error: Unable to open login file for writing. Check folder permissions.";
}

Key Details to Note #

• JSON_PRETTY_PRINT: This flag ensures your JSON is human-readable with proper line breaks and indentation—exactly what you asked for.
• PHP_EOL: Uses the correct newline character for your server’s OS (Windows uses \r\n, Unix uses \n), making the file compatible across systems.
• File Mode: We use 'w' (write mode) here because we’re replacing the entire file with the updated array. If you wanted to append a single JSON object per line (not a valid array), you could use 'a' (append mode), but that wouldn’t be a standard JSON array.
• Permissions: Make sure the $userFolder directory has write permissions set (typically 755 or 775 depending on your server setup), otherwise fopen() will fail.

Example Output JSON #

Your login file will look something like this, with each entry on its own line (formatted for readability):

[
    {
        "user_id": 123,
        "login_timestamp": 1699999999,
        "login_ip": "192.168.1.1",
        "user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36",
        "operating_system": "Windows 10"
    },
    {
        "user_id": 123,
        "login_timestamp": 1700000000,
        "login_ip": "10.0.0.1",
        "user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 14_0) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Safari/605.1.15",
        "operating_system": "macOS"
    }
]

内容的提问来源于stack exchange，提问作者JamesBond