CODEWITHSUNDEEP
iosweb-servicesgoogle-app-enginerestamazon-web-services
Jawap
Jawap

Reputation: 2543

Implementing a sync feature similar to Evernote

The type of content isn't really important for this question, but let's just say I wanted to implement a (native mobile) shopping list app that allowed multiple users to collaborate on a shared list.

How are sync features like this usually implemented that work automatically (without explicit user interaction)? Is the preferred way to pull every few seconds to check for newer versions and update if necessary, or is it possible to push changes?

A polling solution would be (relatively) easy to implement I guess using something like AWS, Google App Engine or even from scratch on a LAMP stack and REST. But I'm worried about traffic resulting from continuous polling.

Would it be practical to try to implement this using push updates? If so, what technologies, services or design principles should I look into? Is something like this possible with AWS or Google App Engine? Or is pulling (and reducing traffic as much as possible) the way to go?

Upvotes: 2

Views: 389

Answers (2)

Guy
Guy

Reputation: 12901

You can use a few of Amazon Web Services to create an effective and responsive service.

If you check out the IOS SDK that you can download from AWS site, you can find in it an example for a service that is using such services: S3_SimpleDB_SNS_SQS_Demo

First you can use SQS, which is the queueing service, which has long polling that will help you to lower the number of requests.

Second you can use SNS, which is the notification (pub/sub) service. It is integrated with SQS, and you can subscribe queues to listen to notifications.

These services (and others) are accessible through the iOS SDK, as well as with other SDKs (Java, .NET, Android...) and REST and SOAP APIs.

Upvotes: 0

Lumpy
Lumpy

Reputation: 3652

On app engine you should look into the channel API. From the overview:

The Channel API creates a persistent connection between your application and Google servers, allowing your application to send messages to JavaScript clients in real time without the use of polling. This is useful for applications that are designed to update the user about new information immediately or where user input is immediately broadcast to other users. Some examples include collaborative applications, multi-player games, and chat rooms. In general, using Channel API is a better choice than polling in situations where updates can't be predicted or scripted, such as when relaying information between human users or from events not generated systematically.

Upvotes: 2

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