CODEWITHSUNDEEP
androidmessaging
PKlumpp
PKlumpp

Reputation: 5233

Chat - receiving a message

I have a question regarding a simple messaging application which I want to write.

Lets say we have 1000 clients. Now client A writes a message to client B.

Of course, client A sends the message to a server which distributes the messages. But the next step is unclear for me:

  1. Does the server send the message to the specific device of client B? If so, how does it address explicitly this device and not send it to the other devices as well?

  2. Or does client B continuously check for new messages on the server which are addressed to client B?

I am not sure if idea 1 is even possible, and what is the best way. But I just want to ask for how it is normally done.

Upvotes: 0

Views: 52

Answers (1)

Rarw
Rarw

Reputation: 7663

Those are both valid ways to create a chat platform. The problem with option 2, which is generally referred to as a "polling" model (where the client "polls" the server for new messages on a regular basis) is scaleability. In your example alone if you have 1000 clients you would have 1000 requests to the server for new messages every interval. To give the appearance of real time messaging this interval needs to be pretty short (i.e. a few minutes at most). If you do the math you can see that the volume of requests can balloon very quickly.

The better approach is option 1. Using something like OpenFire and the Smack API what you're describing - the server sending messages to client B - is possible. You can read more about the APIs here. The idea is the same as push notifications. Client A sends a message to the server which then will "push" that message to Client B. This is scalable and eliminates the need for polling (which kills server resources and the phone' battery with constant HTTP requests).

Upvotes: 2

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