Firebase POST请求报InvalidRegistration，如何获取正确的to参数值？

我已在NodeJS中成功实现Firebase推送通知功能，现需改用Rust通过API实现该功能，但请求失败。

我在Insomnia中发送的请求： #

{  
  "data":{    
    "title":"New Text Message",    
    "image":"https://firebase.google.com/images/social.png",    
    "message":"Hello how are you?"  
  },  
  "to":"iZFSbueRsSJZnjdahRDvZx"
}

Headers:

• Content-Type: application/js
• Authorization: key=MY_SERVER_KEY

收到的响应： #

{    
    "multicast_id": 2360015634720863373,    
    "success": 0,    
    "failure": 1,    
    "canonical_ids": 0,    
    "results": [        
        {            
            "error": "InvalidRegistration"        
        }    
    ]
}

NodeJS中获取的subscription信息： #

{  
  endpoint: 'https://fcm.googleapis.com/fcm/send/eYZWiC4R_Ug:AP99A1bHgyU7jVOf7LEkcVQABVxbPKtFfSvl6jdzo4Xk1gp47xO2S9NaY8EtUvVAb3i2Ru09_iEAZjNpq-R_mY-PmT4Ys9VZ4_m2R49POHvSh6NUiKTe9ixkJYApkk4FpomS1cP8jxEf7',  
  expirationTime: null,  
  keys: {    
    p256dh: 'BGsA9E_T_T_OqHndd7kR55fl-ul2mrhFQiOw9Wr5reGOJOfOXM1_X83X65pGBz01WY3QxGn9TC9zLGuKtH3-Rjk',    
    auth: 'iZFSbueRsSJZnjdahRDvZx'  
  }
}

问题解决： #

1. 正确的to参数来源：你当前使用的auth字段值是错误的，正确的to参数应为endpoint URL中/send/之后的完整注册ID，即：

   eYZWiC4R_Ug:AP99A1bHgyU7jVOf7LEkcVQABVxbPKtFfSvl6jdzo4Xk1gp47xO2S9NaY8EtUvVAb3i2Ru09_iEAZjNpq-R_mY-PmT4Ys9VZ4_m2R49POHvSh6NUiKTe9ixkJYApkk4FpomS1cP8jxEf7
   

2. 请求头修正：请求头里的Content-Type需设置为application/json，而非application/js，该错误也可能导致请求处理异常。

内容的提问来源于stack exchange，提问作者O'Niel