Google Firebase Cloud Notifications (FCM)

This function sends push notifications to Web, Android, iOS, Windows and Mac devices via FCM.

Usage

You can use it by by adding a function to your Hypi Query or Mutation types under the schema. If you don't have these types, add them, if you do, modify them. For example

In your Hypi app schema, you can use the function like by adding one or more methods

type Mutation {
  subscribeFCM(
    action: String = "subscribe",
    token: String!,
    topic: String!
  ): Json @fn(name: "fcm", version: "v1", src: "hypi", env: ["FCM_SVC_ACC_JSON"])

  unsubscribeFCM(
    action: String = "unsubscribe",
    token: String!,
    topic: String!
  ): Json @fn(name: "fcm", version: "v1", src: "hypi", env: ["FCM_SVC_ACC_JSON"])

  sendFCM(
    action: String = "send",
    token: String!,
    message: Json!
  ): Json @fn(name: "fcm", version: "v1", src: "hypi", env: ["FCM_SVC_ACC_JSON"])

  sendToTopicFCM(
    action: String = "send-to-topic",
    topic: String!,
    message: Json!
  ): Json @fn(name: "fcm", version: "v1", src: "hypi", env: ["FCM_SVC_ACC_JSON"])
}

In the app, you can call the function using one of the below examples - replace any info

mutation {
# {
#   sendFCM(
#     message: {
#       data: { new_msg_id: "msg1" }
#       notification: {
#         title: "Hello world"
#         body: "Hello Damion!"
#         image: "https://images.pexels.com/photos/1629781/pexels-photo-1629781.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2"
#       }
#     }
#     token: "<A FCM token>"
#   )
# }

# {
#   subscribeFCM(topic: "courtney", token: "<An FCM token>")
# }

{
  sendToTopicFCM(
    #For example the ID of the room messages are being sent to
    topic:"courtney",
    message: {
      #Any custom object/data you want to pass to the app e.g. the ID of type it should fetch
      data: {new_msg_id: "msg1"},
      notification: {
        title: "Hello world",
        body: "Hello here",
        image: "https://images.pexels.com/photos/1629781/pexels-photo-1629781.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2"
      }
    }
  )
}
}

This example shows the required parameters for this function. Any of the arguments listed below can be freely added. The name sendNotifications is arbitrary, you can name it anything you like. The return type is Json but you can create a custom type and return that instead. Note that the structure of the custom type must match the structure returned from this function.

Note, src is set to hypi in the example above. Leave this. Hypi has published this function and made it public. You can use it as shown in the example above without building/publishing (which will use your serverless allowance).

FCM_SVC_ACC_JSON env is required. You create an environment variable in your Hypi app with this name and provide the value on each instance that uses this function. action - must be one of send,send-multiple,send-to-topic,subscribe,unsubscribe

Env keys

• FCM_SVC_ACC_JSON is required - it is JSON for a Google cloud service account required to access the firebase APIs

Arguments

The function supports a few variants for sending notifications. These are all defined by FCM, their Message type is central to notifications.

Action	Parameters	Description
send		Allows a notification to be sent to 1 device where the token is stored in Hypi
	token_src_type: String	The name of a GraphQL type in the schema where your app stores device notification tokens
	token_src_field: String	The name of a field within the type given by token_src_type
	token_src_id: String	The ID of the type given by token_src_type
	message	The firebase Message to send to the token from getting token_src_id
subscribe		Allows notifications to be sent to 1 or more devices where the tokens are stored in Firebase
	topic	The topic that the given token should be subscribed to
	token	The device token. In the future, any notification sent to the topic will be received by the device
unsubscribe		Unsubscribe a user/device from a given topic
	topic	The topic that the given token should be subscribed to
	token	The device token. In the future, any notification sent to the topic will be received by the device
send-to-topic		Send a push notification to this topic. All devices previously subscribed to the topic will receive a notification
	topic	The name of the topic to send the notification to
	message	The firebase Message to send to the topic

Build & Release

NOTE: This is NOT necessary for this function. Hypi publishes the fcm function, use src: "hypi" as shown in the usage above.

1. Make sure you've logged into the Hypi container register by running docker login hcr.hypi.app -u hypi and enter a token from your Hypi account as the password
2. Build the JAR and copy the dependencies mvn clean package
3. Build the docker image docker build . -t hcr.hypi.app/public/fcm:v1
4. Deploy the function docker push hcr.hypi.app/fcm:v1

fcm is the function name and v1 is the version. Both are important for using the function later.

As one command:

mvn clean package && docker build . -t hcr.hypi.app/public/fcm:v1 && docker push hcr.hypi.app/public/fcm:v1