Loopback 4 how access request authorization token header in authorization component

Question

I have a custom authentication strategy in my loopback 4 app. For authorization, I need to access the request authorization token in the authorization component. The token contains user details. So I have to find current user from token and check if access is allowed or not depending upon their roles.

So how can I access the authorization token in the loopback authorization function?

Thank you in advance

Here is the code

custom-stratery.ts

    async authenticate(request: Request): Promise<any | undefined> {
    
        const token: any = this.extractCredentials(
          request
        );
        console.log('cred' + token)
        if (token!= null || token!= undefined) {
    
          // need to access tokenin authorization file
          const user = await admin.auth().verifyIdToken(token)
      
          const userProfile = await this.userRepository.find({ where: { email: user.email } })
    
          console.log(userProfile)
          return userProfile
        }
        else {
          throw new HttpErrors.Unauthorized(`Authorization header not found.`);
        }
    
extractCredentials(request: Request): any {

    if (!request.headers.authorization) {
      throw new HttpErrors.Unauthorized(`Authorization header not found.`);
    }

    // for example : Basic Z2l6bW9AZ21haWwuY29tOnBhc3N3b3Jk
    const authHeaderValue = request.headers.authorization;

    if (!authHeaderValue.startsWith('Bearer')) {
      throw new HttpErrors.Unauthorized(
        `Authorization header is not of type 'Bearer'.`,
      );
    }

    //split the string into 2 parts. We are interested in the base64 portion
    const parts = authHeaderValue.split(' ');
    if (parts.length !== 2)
      throw new HttpErrors.Unauthorized(
        `Authorization header value has too many parts. It must follow the pattern: 'Basic xxyyzz' where xxyyzz is a base64 string.`,
      );
    const encryptedCredentails = parts[1];

    return encryptedCredentails
  }
   
   }

authorization.ts

export async function basicAuthorization(
  authorizationCtx: AuthorizationContext,
  metadata: AuthorizationMetadata,

): Promise<AuthorizationDecision> {

  // No access if authorization details are missing
  let currentUser: UserProfile;
  // access token here   
  // find current user from token
  // allow access if current user has that role

  } 

      }