If you would like try building data driven mobile and web applications, watch the re:Invent session video to learn more and open the Amazon AppSync console to get started. For pricing details, please see the pricing page. Amazon AppSync is available in multiple regions. For details on region availability, please see the regions detail page. You can use Amazon AppSync to enable scalable, real-time collaboration use cases by broadcasting data from the backend to all connected clients one-to-many or broadcasting data between clients themselves many-to-many.
For example, you can build a second screen scenario where you broadcast the same data to all clients, and users then respond in real time by voting and commenting about what's on the screen. Reference Architecture : Sample Code. You can use Amazon AppSync to power collaborative and conversational applications.
For example, you can build a mobile and web application that supports multiple private chat rooms, offers access to conversation history, and enqueues outbound messages, even when the device is offline.
The input of whatever you connect to it ends up as data in a GraphQL representation — much like whatever you put in a mincer ends up as, well, minced food. Unless you want to miss a couple of excellent jokes. You might say your browser uses GraphQL when exchanging data with a server. They read, update and transfer real time information, respectively. One feature makes GraphQL superior to other text-based communication languages picked by whimsical developers who juggle new technologies.
What makes GraphQL special is a built-in function to pick which data it loads from an API request or what gets sent in. If you created an application for your favorite restaurant chain, you might want to only display the names of meals on the menu and their full descriptions while in the detailed view. The standard version provides a query language in which the developer defines what app data the system needs, omitting any overhead.
For each operation — Query, Mutation, or Subscription — we then need to attach a Resolver that maps it to an appropriate data source. A data source may be any of the following:. It includes a request and a response mapper. The request mapper instructs AppSync where to search data queried by the client. The response mapper then defines how to structure the data so that the response conforms to the schema served by the API.
After all, you can transform the data in the Lambda code in any way you want. This lets you split the logic into separate and reusable pieces of code. Another trick AppSync can do with Resolvers is connecting a data source to a data field instead of connecting it to a whole query.
There are several ways in which you can ensure your API is only accessible to authorized users:. You can also use other authorization methods such as an OpenId provider or custom Lambda logic. The rule is that one of the methods is set as the default one, and it applies to any Query, Mutation, or Subscription unless stated otherwise.
Any additional authorization method needs an explicit Query-level declaration. For our web application that serves user-specific data from multiple sources, AppSync was a perfect foundation for Backend for Frontend. Data might be costly in terms of money and time. You can only contact an external API or database; or run heavy logic if the client application requests a specific field. In all other cases, the query only provides the names of the meals.
In recent months I have been working extensively with AppSync and have grown to love it. With all else being equal, here are my top five reasons you should consider using AppSync instead of API Gateway for your next project.
To implement this, you can use Cognito user groups to control access to the different API endpoints. This is possible with API Gateway, but it takes a lot of work as you can see from the official guide :.
In contrast, this is all I need to implement group-based authorization in AppSync. One of the under-appreciated features of API Gateway is the fact that it can perform request validation for you.
Requests that fail the schema validation do not incur costs. You have to implement response validation in your application code.
Libraries such as middy has support for this through the validator middleware. Anyone with an HTTP proxy can snoop the data. This affords you more time to think about your domain and how best to model it with types, and less time worrying about the mechanics of request and response validation. You, as the application developer, have to maintain the mapping of the WebSocket connection to users or groups. Again, this is a very low-level construct and puts a lot of the heavy-lifting on your shoulders.
And it can be very cost-inefficient for implementing group chats or broadcasts. If you have a million viewers for that match, then that translates:. For example, 1—2—1 private chat, or even group chats where you can limit the size of the group.
By comparison, AppSync subscriptions are a breeze to work with. And since AppSync announced support for pure WebSockets it can now support millions of connected clients.
0コメント