Shared context

Shared context between functions across the execution chain

The shared context is a key factor in the middleware functions standardization. It helps to share data between functions, make it easier to maintain, and improve the development experience. A well-structured context can help developers to understand the codebase faster, find the data they need, and make changes more efficiently.

Usage

Below you can see an example of how to use the shared context in your middleware functions.

async ({ request, response, context, event }: MiddlewareFunctionProps) => {
  let user = undefined; 
 
  if(!context.has('user')) { 
    user = await fetchUser(); 
    context.set('user', user); 
  } else { 
    user = context.get('user'); 
  } 
 
  if(!user) {
    return NextResponse.json({ message: 'Unauthorized' }, { status: 401 });
  } else {
    response.headers.set('x-user-id', user.id);
    return response
  }
}

Explanation

In this example, we are using the shared context to store the user data. We are checking if the user data is already stored in the context. If not, we are fetching the user data and storing it in the context. Then we are using the user data to set a custom header in the response object.

By using the shared context, we can avoid fetching the user data multiple times in the same request, which can improve the performance of the application. We can also share the user data between multiple functions in the execution chain, which can make the code more maintainable and easier to understand.