PHP cURL发送JSON数据：PayPal API集成中的变量处理技巧

$planID = 'P-25Y56437062492726MFWZ4GI';
$startTime = '2021-10-22T00:00:00Z';

curl_setopt($ch, CURLOPT_POSTFIELDS, "\n  {\n   \"plan_id\":$planID,\n   \"start_time\":$startTime,\n      \"application_context\": {\n        \"brand_name\": \"Sleep Happy Mattress\",\n        \"locale\": \"en-US\",\n        \"shipping_preference\": \"SET_PROVIDED_ADDRESS\",\n        \"user_action\": \"SUBSCRIBE_NOW\",\n        \"payment_method\": {\n          \"payer_selected\": \"PAYPAL\",\n          \"payee_preferred\": \"IMMEDIATE_PAYMENT_REQUIRED\"\n        },\n        \"return_url\": \"https://example.com/returnUrl\",\n        \"cancel_url\": \"https://example.com/cancelUrl\"\n      }\n    }");

{
   "plan_id":P-25Y56437062492726MFWZ4GI,
   "start_time":2021-10-22T00:00:00Z,
   // ...
}

<?php

// 1. 定义PHP变量
$planID = 'P-25Y56437062492726MFWZ4GI';
$startTime = '2021-10-22T00:00:00Z'; // 注意：实际应用中，startTime应动态生成，例如：date('Y-m-d\TH:i:s\Z', strtotime('+1 day'))

// 2. 构建PHP关联数组，与PayPal API期望的JSON结构对应
$data = [
    'plan_id' => $planID,
    'start_time' => $startTime,
    'application_context' => [
        'brand_name' => 'Sleep Happy Mattress',
        'locale' => 'en-US',
        'shipping_preference' => 'SET_PROVIDED_ADDRESS',
        'user_action' => 'SUBSCRIBE_NOW',
        'payment_method' => [
            'payer_selected' => 'PAYPAL',
            'payee_preferred' => 'IMMEDIATE_PAYMENT_REQUIRED'
        ],
        'return_url' => 'https://example.com/returnUrl',
        'cancel_url' => 'https://example.com/cancelUrl'
    ],    
];

// 3. 将PHP数组编码为JSON字符串
$jsonEncodedData = json_encode($data);

// 检查json_encode是否成功，尤其是在调试阶段很有用
if ($jsonEncodedData === false) {
    echo "JSON编码失败: " . json_last_error_msg();
    exit;
}

// 4. 初始化cURL会话
$ch = curl_init();

// 5. 设置cURL选项
curl_setopt($ch, CURLOPT_URL, 'https://api-m.sandbox.paypal.com/v1/billing/subscriptions');
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false); // 在生产环境中应设置为true并配置CA证书
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);

// 设置HTTP头部，特别是Content-Type为application/json
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Content-Type: application/json',
    // 假设您已经获取并设置了Authorization头部，例如：
    // 'Authorization: Bearer YOUR_ACCESS_TOKEN' 
]);

// 设置POST请求体为JSON字符串
curl_setopt($ch, CURLOPT_POSTFIELDS, $jsonEncodedData);

// 6. 执行cURL请求
$response = curl_exec($ch);

// 检查cURL错误
if (curl_errno($ch)) {
    echo 'cURL Error: ' . curl_error($ch);
} else {
    // 处理API响应
    echo "API Response: " . $response;
    // 在生产环境中，您可能需要解析JSON响应并检查其状态
    $responseData = json_decode($response, true);
    if (json_last_error() === JSON_ERROR_NONE) {
        // 成功解析响应
        print_r($responseData);
    } else {
        echo "无法解析API响应: " . json_last_error_msg();
    }
}

// 7. 关闭cURL会话
curl_close($ch);

?>