feat(server-auth): dbAuth 3/3 - handle login, logout, signup, etc. requests if forwarded from middleware

[dac09]

Closes #10448

This PR updates the DbAuthHandler class to handle requests forwarded from middleware, so it can generate responses for login, logout, signup, etc. These are POST requests - it used to be to the /auth function, but now they will be captured by dbAuth middleware and forwarded onto DbAuthHandler.

High level changes:

• use the Headers class in each of the "method" responses. This allows us to set multi-value headers like Set-Cookie. A simple object would not. See type AuthMethodOutput
• extracts buildResponse into a testable function and adds test. For Set-Cookie headers we return an array of strings.

In the middleware here's the code I had for the final conversion:

    if (AUTHHANDLER_REQUEST) {
      const output = await dbAuthHandler(req)

      const finalHeaders = new Headers()
      Object.entries(output.headers).forEach(([key, value]) => {
        if (Array.isArray(value)) {
          value.forEach((v) => finalHeaders.append(key, v))
        } else {
          finalHeaders.append(key, value)
        }
      })

      return new MiddlewareResponse(output.body, {
        headers: finalHeaders,
        status: output.statusCode,
      })
    }

Tasks

• Sanity check on graphql-based dbAuth for backwards compatibility with DT
• Validate on SSR test project along with changes in feat(server-auth): Part 1/3: dbAuth middleware support (web side changes) #10444

[dthyresson]

@dac09 Confirmed login, logout, signup and currentUser work in classic GraphQL app.

Both session and auth-provider cookies are set ... and cleared on logout.

See the change the the test import in packages/auth-providers/dbAuth/api/src/__tests__/buildDbAuthResponse.test.ts but LGTM and approved to

[dthyresson]

@dac09 This test fails locally as it points to a local package with your "dac" path.

[dthyresson]

@dac09 Changing to "import { buildDbAuthResponse } from '../shared'" fixes test run. I'll post the change

[dthyresson]

Suggested change

	import { buildDbAuthResponse } from '/Users/dac09/Code/redwood/packages/auth-providers/dbAuth/api/src/shared'
	import { buildDbAuthResponse } from '../shared'

[dthyresson]

I committed the change FYI

[dac09]

Thanks!