求助：Firebase FCM从Legacy API迁移至HTTP v1 API的PHP脚本实现

核心差异说明 #

FCM HTTP v1 API和旧版Legacy API的核心区别在于两点：

• 身份验证从固定服务器密钥改为OAuth 2.0访问令牌
• 请求体格式更严格，需嵌套在message字段下，API端点包含项目ID

完整实现代码 #

1. 获取OAuth 2.0访问令牌 #

从Firebase控制台下载服务账号JSON密钥，提取client_email和private_key字段，用以下函数生成有效期1小时的访问令牌：

function getFcmAccessToken($clientEmail, $privateKey) {
    $tokenUrl = "https://oauth2.googleapis.com/token";
    
    // 构造JWT Header
    $header = json_encode(["alg" => "RS256", "typ" => "JWT"]);
    // 构造JWT Payload
    $now = time();
    $payload = json_encode([
        "iss" => $clientEmail,
        "scope" => "https://www.googleapis.com/auth/firebase.messaging",
        "aud" => $tokenUrl,
        "exp" => $now + 3600,
        "iat" => $now
    ]);
    
    // Base64URL编码Header和Payload
    $base64Header = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($header));
    $base64Payload = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($payload));
    
    // 生成签名
    $signatureInput = $base64Header . "." . $base64Payload;
    openssl_sign($signatureInput, $signature, $privateKey, "SHA256");
    $base64Signature = str_replace(['+', '/', '='], ['-', '_', ''], base64_encode($signature));
    
    $jwt = $base64Header . "." . $base64Payload . "." . $base64Signature;
    
    // 请求获取访问令牌
    $curl = curl_init($tokenUrl);
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query([
        "grant_type" => "urn:ietf:params:oauth:grant-type:jwt-bearer",
        "assertion" => $jwt
    ]));
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_HTTPHEADER, ["Content-Type: application/x-www-form-urlencoded"]);
    
    $response = curl_exec($curl);
    curl_close($curl);
    
    $responseData = json_decode($response, true);
    return $responseData["access_token"] ?? null;
}

2. 发送FCM通知 #

使用获取到的访问令牌，构造符合v1 API格式的请求：

function sendFcmNotification($accessToken, $projectId, $deviceToken, $title, $body) {
    $apiUrl = "https://fcm.googleapis.com/v1/projects/{$projectId}/messages:send";
    
    $requestBody = json_encode([
        "message" => [
            "token" => $deviceToken,
            "notification" => [
                "title" => $title,
                "body" => $body
            ],
            // 可选：添加自定义数据负载
            "data" => [
                "order_id" => "12345",
                "status" => "shipped"
            ]
        ]
    ]);
    
    $curl = curl_init($apiUrl);
    curl_setopt($curl, CURLOPT_POST, true);
    curl_setopt($curl, CURLOPT_POSTFIELDS, $requestBody);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_HTTPHEADER, [
        "Authorization: Bearer {$accessToken}",
        "Content-Type: application/json"
    ]);
    // 建议开启SSL验证，避免安全风险
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, true);
    
    $response = curl_exec($curl);
    $httpCode = curl_getinfo($curl, CURLINFO_HTTP_CODE);
    curl_close($curl);
    
    return [
        "http_code" => $httpCode,
        "response" => json_decode($response, true)
    ];
}

3. 调用示例 #

// 替换为你的实际信息
$clientEmail = "your-service-account@your-project.iam.gserviceaccount.com";
$privateKey = "-----BEGIN PRIVATE KEY-----\nYOUR_PRIVATE_KEY_CONTENTS\n-----END PRIVATE KEY-----";
$projectId = "your-firebase-project-id";
$deviceToken = "target-user-fcm-token";

// 获取访问令牌
$accessToken = getFcmAccessToken($clientEmail, $privateKey);
if (!$accessToken) {
    die("获取访问令牌失败");
}

// 发送通知
$result = sendFcmNotification($accessToken, $projectId, $deviceToken, "新订单提醒", "您的订单已发货");
print_r($result);

重要注意事项 #

• 私钥格式：确保私钥包含完整的首尾标记，换行符保留正确格式
• 令牌缓存：访问令牌有效期1小时，建议缓存令牌减少重复请求
• SSL验证：不要随意关闭CURLOPT_SSL_VERIFYPEER，若托管环境有证书问题，联系服务商解决
• 错误排查：若请求失败，检查HTTP状态码，常见问题包括令牌过期、设备令牌无效、项目ID错误

内容的提问来源于stack exchange，提问作者FreddyBoy