Scope:
I have an app that i am starting to build that has the "subscriber/publisher" situation on it's core.
For those who don't know, the idea behind this schema is that:
1) Someone creates a "Topic"
2) Endpoints subscribe to a "Topic"
3) Any message published to a certain "Topic" is pushed to the subscribers of said "Topic"
Considerations:
I am going to use Xamarin.IOS and Xamarin.Android as the framework to build this mobile app (so that it can be crossplatform from the begining).
RabbitMQ:
The RabbitMQ service is built on top of the AMQP pattern which solves my entire problem of modeling the "Topic/Subscriber/Publisher" problem.
The Problem:
Now that I have the problem modeled via the RabbitMQ framework, I need those "Messages" that are "pushed" to each endpoint (mobile device) to actually be a "Push Notification" instead of the standard message that will arrive to that device.
How can I model my solution to accomplish that ?
Thanks in advance.
RabbitMQ can't send out the push notification itself.
For each message consumed from the a RabbitMQ queue, the "Consumer" service needs to invoke whatever push notification backend/API you are using (e.g. Firebase, AWS, etc.) using their SDK.
Related
I want to implement a connected OAuth app in Salesforce which should trigger push events in case some entities changed, for example an opportunity was closed.
Zapier implemented something similar
https://zapier.com/apps/salesforce/integrations/webhook
Could not find something I need which is a simple way to subscribe to entity changes using the OAuth client's token and passing a webhook endpoint. I read about apex callouts, streaming API and outbound messages.
Yeah, we solved this exact problem at Fusebit and I can help you understand the process as well.
Typically speaking here's what you need to do:
Create triggers on the Salesforce Objects you want to get updates for
Upload Apex class that will send an outgoing message to a pre-determined URL
Enable Remote Site Setting for the Domain you want to send the message to
Add in Secret Verification (or other auth method) to prevent spamming of your external URL
If you're leveraging javascript, then you can use the jsforce sdk & salesforce tooling API to push the code into the salesforce instance AFTER the Auth flow has occurred AND on Salesforce Instances that have API access enabled (typically - this is enterprise and above OR professional with API enabled).
This will be helpful for you to look through: https://jamesward.com/2014/06/30/create-webhooks-on-salesforce-com/
FYI - Zapier's webhooks implementation is actually polling every 15 minutes, instead of real-time incoming events.
In which programming language?
For consuming outbound messages you just need to be able to accept an XML message and send back "Ack" message to acknowledge receiving, otherwise SF will keep trying to resend it for 24h.
For consuming platform events / streaming API / Change Data Capture (CDC) you'll need to raise the event in SF (Platform Event you could raise from code, flow, process builder, CDC would happen automatically, you just tell it which objects it should track).
And then in client app you'd need to login to SF (SOAP or REST API), subscribe to channel (any library that supports cometd should be fine). Have you seen "EMP Connector", mentioned for example in https://trailhead.salesforce.com/en/content/learn/modules/change-data-capture/subscribe-to-events?trail_id=architect-solutions-with-the-right-api ?
Picking right messaging way is an art, there's free course that can help: https://trailhead.salesforce.com/en/content/learn/trails/architect-solutions-with-the-right-api
And pretty awesome PDF if you want to study for certification: https://resources.docs.salesforce.com/sfdc/pdf/integration_patterns_and_practices.pdf
I got the following message from apple.
"The HTTP / 2-based Apple Push Notification Service Provider (APN) API lets you take advantage of great features like authentication with a JSON web token, improved error messages, and per-notification feedback. If you are still sending push notifications with the legacy binary protocol, make sure to update to the APN provider's API as soon as possible. APNs will no longer support the legacy binary protocol after March 31, 2021."
I have to investigate if it is going to impact the project.
Currently notifications are handled by a plugin called: phonegap-push-notification, with a forked havesoruce.
But I can't find or don't see where in the plugin it uses what apple wants to modify. I don't know if the changes will impact, I don't know if when updating the plugin, the apple changes will be made in the system.
How do I know if my app uses legacy binary protocol, where do I see that?
APP:use ionic 3, AngularJs.
I have built Salesforce platform event client using CometD java and It's similar to example EMP-Connector provided by forcedotcom.
I installed this client on OpenShift cloud and my app is running with 2 pods. Problem I am facing is that since there are two pods and each are running the same docker image thus both are getting the same of event. That means duplication event.
Per my understanding, Salesforce platform event should behave like Kafka subscriber.
I am unable to find a solution about how to avoid getting the same copy of events. Any suggestions here would be the great help.
Note: As of now I am able to create client side solution which drop duplicate copy of event. which is not an optimal solution.
I have to run my app atleast with 2 pods. That's limit I have on my cloud.
This is expected / by design. In CometD, when a message is published on a broadcast channel all subscribers listening on this channel will receive a copy of this message. The broadcast channel behaves like a messaging topic where one sender wants to send the same info to multiple recipients. There are other types of channels in CometD with different semantics. The broadcast channel and one-to-many message semantics is what you get with platform events available via CometD in Salesforce.
In your case it sounds like you have multiple subscribers, thus what you're seeing is expected. You can deduplicate the message stream on the client side as you have done or you can change your architecture so that you have a single subscription.
Every example for GAE Chats uses some kind of polling. However, if my GAE app holds a list of clients (in the datastore if necessary), perhaps I could avoid polling by sending a message to all these clients. How can I achieve this?
If you are talking about HTTP, the short answer is that GAE does not currently support it. What I think you are asking about is sometimes called BOSH. Once WebSockets become more widespread, they will be an excellent solution for this problem.
In the mean time you might want to look at XMPP. Using XMPP you can avoid polling. Google has announced a Channel API (yet to be released) which will basically give you the same features as websockets.
You've probably seen some chat room examples...
Since you just want to send a message to users on your datastore (Tip: the IMProperty is great to store such data), it's just a matter of directly sending the message:
from google.appengine.api import xmpp
# `destination` is a list of JIDS
# `message` is a normal unicode string
xmpp.send_message(destination, message)
You can find a great tutorial on using XMPP by Nick Johnson here
Note that you can now use the App Engine Channel API for this: http://code.google.com/appengine/docs/python/channel/
You can create a channel for a given client using:
channel.create_channel(client_id)
Then when you want to update that client, send a message:
channel.send_message(client_id, message)
Basically each client will get a persistent connection that you can push messages over.
Can anyone think of a good way to allow the server to notify the client based upon server processing? For example, consider the following events:
A user requests a deletion of data, however, due to it's long-running time, we kick it off to a queue.
The client receives a "Yes we completed your transaction successfully".
The server deletes the item and now wants to update any local structures any clients may be using (I'd also like to notify the user).
I know this can be done by client-side polling. Is there a event bus type way to do this? Any suggestions are welcome, but please keep in mind I am using GWT with App Engine.
The standard AJAX interaction is that the client sends requests to the server and expects some sort of response back fairly quickly.
In order for the server to initiate a request to the client, you will need to use WebSockets, and experimental HTML5 feature currently only supported by Chrome.
Or, to simulate this kind of interaction, you can use Comet (long-polling), made available in GWT by the rocket-gwt project.
You want server events for GWT? Have a look at GwtEventService (they couldn't have chosen a better name): http://code.google.com/p/gwteventservice/wiki/StartPage
Of course, it uses a Comet implementation, but you can't do any different when using HTTP, the client always initiates the communication. Request, response.