android - Firebase Cloud functions to Android application notifications

Question

I need some hints for the following system:

• client app: Android
• backend: Firebase Cloud Funtions
• database: realtime database

One of the scenarios is as follows:

• All users are on android devices.

• Users are sign-in via OAuth2 (google accounts).

  1. User1 creates an offer and the offer is 'waiting' in active offers list.
  2. Other users are notified for the change is active offers list..
  3. User2 requests the offer and the offer is 'requested'
  4. Other users are notified for the change is active offers list..
  5. User 1 is notified for the User2's request

  6. User1 confirms/denies the User1's request:

     a) confirms and the offer is 'completed' and removed from the active offers list.

     b) denies and the offer is again 'waiting' in the active offers list.

  7. Other users are notified for the change is active offers list..
  8. User2 is notified for the User1's confirmation/denial

NOTE: System is specific and limited so the active offers list will be short enough and that's why currently I'm thinking about notifying users about list modifications and not about a single offer modification, but I'm open for advices.

==========================================

Currenty I've implemented the following:

1. User1 creates an offer and the offer is 'waiting':

   • android app calls createOffer(...) firebase cloud function
   • createOffer(...) adds a new offer to the offers list in realtime database.
   • onWrite(...) realtime database trigger is fired on active offers list level

2. here I need the hint

3. User2 requests the offer and the offer is 'requested':

   • android app calls requestOffer(...) firebase cloud function
   • requestOffer(...) modifies the offer in realtime database.
   • onWrite(...) realtime database trigger is fired on active offers list level

4. here I need the hint

5. here I need the hint

6. User1 confirms/denies the User1's request:

a) confirmation:

• android app calls confirnOfferRequest(...) firebase cloud function
• confirmOfferRequest(...) removes the offer from active offers list.
• onWrite(...) realtime database trigger is fired on active offers list level

b) denial:

• android app calls denyOfferRequest(...) firebase cloud function
• denyOfferRequest(...) modifies the offer in active offers list. onWrite(...) realtime database trigger is fired on active offers list level.

.

7. here I need the hint

8. here I need the hint

==================================

So I need hints about notifications to android application: steps 2, 4, 5, 7, 8

I guess I should use FCM, but:

1. Android tutorials I find are about the deprecated FirebaseInstanceId

2. I'm not sure what is my case:

   • topic messages
   • device groups
   • upstream messages

3. I'm not sure how to notify android app by onWrite(...) realtime database trigger.

4. Signed-in users only should be notified about active offers list changes. if a user is singed-out should not be notified and when sign-in should get actual state (active offers list).

=============

@James Poag, Thank you for the hints. I'll try and give feedback.

I have some questions:

When I said "notification" I didn't mean 'real' notification in device's 'status bar'. At least current plan is the application to show the info inside itself - this I called "notification". It seems simpler.

1. is there a reason to use onCreate() instead of onWrite() ?

Currently my plan is to perform same action on creating/updating an offer so I thought onWrite() would do the trick for both cases. Or not ?

3. thanks for transaction hint :)

4. I guess in my case I have "data" messages, not "real" notifications.

---

I have to read about the permissions. thanks.

Currenty I check for authorization this way:

if (!context.auth) {
    return Promise.reject(Error('User is not authenticated.'));
}

标签： androidfirebasefirebase-cloud-messaginggoogle-cloud-functions

Answer 1

以下要点是您要使用Admin SDK 发送消息。

您可以创建主题，让用户订阅主题，然后向主题发送消息（在上面的同一链接中介绍），或者如果有一小部分用户，那么也许您只想向数据库中的每个人发送消息。

此外，不要依赖 Android 中的默认通知处理来处理您的 FCM 消息，请使用步骤 #2 中的链接手动将通知发布到用户的托盘。

---

1. User1 创建了一个报价并且报价正在“等待”：

   • android 应用调用 createOffer(...) firebase 云函数
   • createOffer(...) 在实时数据库中的报价列表中添加一个新报价。
   • onWrite(...) 在活动商品列表级别触发实时数据库触发器考虑使用 onCreate() 而不是 onWrite()

2. 使用 admin sdk 向您的应用用户发送通知。这将需要发送到组主题或遍历用户数据库并发送到用户的设备令牌。当您的用户使用设备登录时，从 FirebaseMessaging 获取他们的令牌并将其写入保存其个人资料的实时数据库。

3. User2 请求报价并且报价被“请求”：

   • android 应用调用 requestOffer(...) firebase 云函数
   • requestOffer(...) 在实时数据库中修改报价。在这里，您需要查看交易以防止多个用户获得对 Offer 的锁定
   • onWrite(...) 实时数据库触发器在活动报价列表级别触发

4. 向主题组发送data唯一通知。在您的 Android 应用程序中，处理数据负载，打开NotificationManager并将之前的通知更新为“已请求”。

5. *在数据库中创建报价时，请务必包含所有者的设备令牌。这样，当报价状态更改为“已请求”时，您可以使用 admin sdk 向所有者发出通知。*

6. User1 确认/拒绝 User1 的请求：

a) 确认：

• android 应用调用 confirnOfferRequest(...) firebase 云函数
• confirmOfferRequest(...) 从活动报价列表中删除报价。
• onWrite(...) 实时数据库触发器在活动报价列表级别触发

b) 否认：

• android应用调用denyOfferRequest(...) firebase云函数
• denyOfferRequest(...) 修改活动报价列表中的报价。onWrite(...) 实时数据库触发器在活动报价列表级别触发。

.

7. ** 与#4 相同，但如果接受，则使用通知管理器完全取消通知 **

8. 当 User2 触发第 3 步时，他们应该将他们的设备令牌作为请求的一部分发送。这样，当请求被接受时，您的云功能将知道该通知谁。

---

当用户登录设备时，将他们的令牌发送到主题组。当他们注销时，从组中删除令牌（在实际注销之前）。

由于所有内容都通过您的云功能进行路由，因此您可以将数据库上的权限设置为.read : false, .write : false，然后对于配置文件部分（如果需要），您可以添加一个特殊的.write : auth !== null && auth.user === uid. 否则，Admin SDK 具有从您的数据库读取/写入的特殊权限。

此外，当有人调用您的 HTTPS 函数时检查授权，以确保他们已登录 Firebase。