2015.08.27 Android Taipei Google Cloud Messaging by DiQI Android developer 張鈞為

1. 我的GCM時代
-推送訊息的實做分享
DIQI ANDROID APP DEVELOPER
台大資工所 張鈞為

2. Push and Pull Message
What is push message?
◦ Server 主動推送訊息到app端。
What is pull message?
◦ App 主動向Server 索取需要的訊息。
Why push is more difficult than pull?
◦ The IP address of each mobile device always change.
◦ Therefore, if we want to solve this problem, we have to set timer to connect to server periodically.
Fortunately, there are some useful tools to deal with this problem.
◦ Ex. Google cloud messaging

3. 何時會用到推送訊息
最常見的就是Notification！

4. GCM overview
Google Cloud Messaging (GCM) is a service that allows
◦ Send data from your server to your Android device
◦ Receive messages from devices on the same connection.
It can deal with push message problem!

5. Two kinds of messages
Collapsible message
◦ May be replaced by a new message containing the same collapse key.
◦ Only the most recent message is relevant.
◦ Ex. Send-to-sync messages
Non-collapsible message
◦ Each individual message is delivered to the device.
◦ Ex. IM

6. Key Concepts
Components
◦ Client App
◦ 3rd-party Application Server
◦ GCM Connection Servers
Credentials
◦ Sender ID - Google API project ID
◦ Application ID – App’s Package name
◦ Registration ID – Issued by the GCM servers to the Apps. (Each device has one reg_id)
◦ Google User Account
◦ Sender Auth Token - API Key. Use as password in server

7. Architectural Overview

8. GCM Client
Use GoogleCloudMessage API
◦ Setup google play service SDK in the project.
Modify Manifest file
◦ Allow some permission (like internet…)
◦ Set a Receiver to receive GCM’s broadcast
◦ Set a Service to handle GCM message
Register for GCM
◦ Each device needs to register a unique registration ID.
◦ Let server keep the Reg id.
You can also implement
◦ User notification
◦ …

9. GCM Server
Two kinds of connections:
◦ GCM HTTP
◦ Downstream only: cloud-to-device.
◦ Synchronous messaging
◦ HTTP POST
◦ CCS(Cloud Connection Server, XMPP)
◦ Upstream and downstream (device-to-cloud, cloud-to-device).
◦ Asynchronous messaging
◦ JSON in XMPP message
Use device’s registration ID to send message.

10. GCM samples
單向：
Gmail : send notification after new mails arrived.
交通公具app：Server當車在進站前五分鐘、十分鐘時，提前通知使用者到站等候。

11. GCM samples
雙向：
◦ Aipu store(DiQi product)：
在一開始的版本中，所有的傳輸都是使用GCM。
(現在的版本則是使用自己架的接口，原因稍後會說)
◦ Problem spider(和朋友合作的 prototype app) :
我們所有server和app之間的傳送都使用GCM。

12. However...
GCM 雖然方便，但是也有其做不到的地方。
◦ GCM在台灣國內或是世界絕大數國家都是十分方便的服務，但是總有例外。
◦ 在中國，因中國政府官方會擋google的所有服務，所以在中國要開發相關的功能時，就無法使用
GCM了。
◦ 還好，中國各大互聯網都有類似的服務。
◦ Ex. 百度、騰迅…。

13. 百度雲推送(百度云推送)
由百度開發的雲端服務之一。以下為幾個特點。
◦ Server端有提供java, php的開發套件。
◦ Application端有提供android及ios。
◦ 網頁管理頁面。
雖然解決了中國無法使用GCM的問題，不過他本身不像GCM方便。雲推送僅提供推送
(push message, cloud-to-device)單向的服務。

14. Comparison
GCM:
◦ Pros: Easy to develop. GCM API can be simply used in Android Studio. (Google play service)
◦ Can send message in both direction.
◦ Cons: GCM cannot be used in China.
百度雲：
◦ 優點：解決在中國無法使用的問題。
◦ 缺點：僅能單向傳遞訊息。
◦ 其實不太容易import到自己的project中。

15. Reference
GCM官方教學：
https://developers.google.com/cloud-messaging/
百度雲：
http://developer.baidu.com/cloud/push

16. Thank you for listening