Update auth middleware interface

[dmihalcik-virtru]

The current auth middleware API is

export type AuthProvider = {
  updateClientPublicKey(signingKey?: CryptoKeyPair): Promise<void>;
  withCreds(httpReq: HttpRequest): Promise<HttpRequest>;
};

However, this doesn't have a good way to perform refreshes, or generate an updated DPoP when receiving a DPoP nonce. The middleware needs to have a method that takes an error.

One reason we held off on this is because we want to support both axios and fetch interfaces.

Nice to haves:

• chainable: we can do dpop updates with nonce and refresh token updates as separate objects
• simple to call
• works with both fetch and axios?

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Some options:

Aspect oriented:

export type AuthMiddleware = {
  onRequest(req: HttpRequest): Promise<HttpRequest>;
  onResponse(req: HttpRequest, resp: HttpResponse): Promise<HttpRequest>;
};

With sub-object:

export type AuthMiddleware = {
  withHandler(resource: string; options: FetchOptions): MiddlewareHandler;
};

export type MiddlewareHandler = {
  handle(resp: Promise<Response>): Promise<Response>;
};

Interceptors:

export type FetchInterceptor = {
  bind(f: typeof window.fetch): typeof window.fetch;
};

????

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Code Samples: Interceptors

???