How can PHP be used to assign unique IDs to each file uploaded through multiple input fields?

When uploading multiple files through input fields in PHP, we can use a combination of a timestamp and a unique identifier to assign a unique ID to each file. This can be achieved by concatenating the current timestamp with a randomly generated string using the uniqid() function. This ensures that each file uploaded will have a distinct identifier. 

// Loop through each uploaded file
foreach($_FILES['file']['name'] as $key=>$value){
    $timestamp = time(); // Get current timestamp
    $unique_id = uniqid(); // Generate unique identifier
    $file_id = $timestamp . '_' . $unique_id; // Concatenate timestamp and unique id
    
    // Process the uploaded file with the assigned unique ID
    $file_name = $_FILES['file']['name'][$key];
    $file_tmp = $_FILES['file']['tmp_name'][$key];
    
    // Move the uploaded file to a specific directory with the unique ID as the filename
    move_uploaded_file($file_tmp, 'uploads/' . $file_id . '_' . $file_name);
}

Keywords

PHP unique IDs file upload multiple input fields file handling

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