4.4.2. Build helpers

In the auth module, there will be something a little more special, which is that it has helper functions, so in this part we will set up those functions. First, create some files such as get-authorization-token.ts, get-info-from-claims.ts and get-public-keys.ts.

Get authorization token helper

Open the get-authorization-token.ts file and add the following code.

Import some things first

// Import errors
import { AppError, ClientError, isStandardError } from "../../../error";

// Import types
import type { InternalContext } from "../../../context/internal-context";

/**
 * Lấy token từ trong headers. Mặc định sẽ lấy Bearer token.
 *
 * @param ctx - runtime context
 *
 * @returns
 */
export function getAuthorizationToken(
  ctx: InternalContext,
): string | undefined {
  try {
    const headers = (ctx.params as any).headers;

    const authHeader =
      headers.Authorization ||
      headers.authorization || // fallback lowercase nếu dùng HTTP API
      null;

    if (!authHeader || !authHeader.startsWith("Bearer ")) {
      const err = new ClientError("Missing or invalid Authorization header");
      err.addErrorDetail({ source: "getAuthorizationToken" });
      err.asHTTPError("BadRequest");
      throw err;
    }

    const token = authHeader.split(" ")[1];

    if (!token) {
      const err = new ClientError("Bearer token not found");
      err.addErrorDetail({ source: "getAuthorizationToken" });
      err.asHTTPError("BadRequest");
      throw err;
    }

    return token;
  } catch (error: any) {
    let err = error;

    if (!isStandardError(err)) {
      err = new AppError("Cannot get token from authorization header");
      err.addErrorDetail({
        source: "getAuthorizationToken",
        desc: error.message,
      });
      err.asHTTPError("InternalServerError");
    }

    if (ctx.options && ctx.options.canCatchError) {
      throw err;
    }

    return;
  }
}

In this function, I want us to be able to get the value of the Bearer Token to use in the later stages of the process.

4.4.2.1

Get Information from claims helper

Open the get-info-from-claims.ts file and add the following code.

Import some things first.

import axios from "axios";

// Import constants
import { Configs } from "../../../../utils/configs";

// Import errors
import { AppError } from "../../../error";

/**
 * Tổng hợp và lấy thông tin người dùng trong cognito claims.
 *
 * @param claims - cognito claims.
 *
 * @returns
 */
export function getInfoFromClaims(claims: any) {
  return {
    username: claims.username,
    team: claims["cognito:groups"][0],
    role: claims["custom:role"],
  };
}

4.4.2.2

Get public keys helper

Open the get-public-keys.ts file and add the following code.

Import some things first.

import axios from "axios";

// Import constants
import { Configs } from "../../../../utils/configs";

// Import errors
import { AppError } from "../../../error";

const region = Configs.AWSRegion;
const userPoolId = process.env.COGNITO_USER_POOL_ID;
const jwksURL = `https://cognito-idp.${region}.amazonaws.com/${userPoolId}/.well-known/jwks.json`;

/**
 * Lấy các public keys trong cognito user pool.
 *
 * @returns
 */
export async function getPublicKeys(): Promise<Array<any> | AppError> {
  try {
    const response = await axios.get(jwksURL);
    const data = response.data;
    return data.keys as Array<any>;
  } catch (error: any) {
    const err = new AppError("Cannot get public keys from Cognito User Pool");
    err.asHTTPError("InternalServerError");
    err.addErrorDetail({ source: "getPublicKeys", desc: error.message });
    return err;
  }
}

4.4.2.3

Ok, we have finished building the necessary helper functions in this module.