user_context.go

/*
Copyright 2015 All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package main

import (
	"fmt"
	"strings"
	"time"

	"github.com/coreos/go-oidc/jose"
	"github.com/coreos/go-oidc/oidc"
)

// extractIdentity parse the jwt token and extracts the various elements is order to construct
func extractIdentity(token jose.JWT) (*userContext, error) {
	// step: decode the claims from the tokens
	claims, err := token.Claims()
	if err != nil {
		return nil, err
	}
	// step: extract the identity
	identity, err := oidc.IdentityFromClaims(claims)
	if err != nil {
		return nil, err
	}
	// step: ensure we have and can extract the preferred name of the user, if not, we set to the ID
	preferredName, found, err := claims.StringClaim(claimPreferredName)
	if err != nil || !found {
		// choice: set the preferredName to the Email if claim not found
		preferredName = identity.Email
	}
	// step: retrieve the audience from access token
	audience, found, err := claims.StringClaim(claimAudience)
	if err != nil || !found {
		return nil, ErrNoTokenAudience
	}
	// step: extract the realm roles
	var list []string
	if realmRoles, found := claims[claimRealmAccess].(map[string]interface{}); found {
		if roles, found := realmRoles[claimResourceRoles]; found {
			for _, r := range roles.([]interface{}) {
				list = append(list, fmt.Sprintf("%s", r))
			}
		}
	}

	// step: extract the roles from the access token
	if accesses, found := claims[claimResourceAccess].(map[string]interface{}); found {
		for roleName, roleList := range accesses {
			scopes := roleList.(map[string]interface{})
			if roles, found := scopes[claimResourceRoles]; found {
				for _, r := range roles.([]interface{}) {
					list = append(list, fmt.Sprintf("%s:%s", roleName, r))
				}
			}
		}
	}

	return &userContext{
		id:            identity.ID,
		name:          preferredName,
		audience:      audience,
		preferredName: preferredName,
		email:         identity.Email,
		expiresAt:     identity.ExpiresAt,
		roles:         list,
		token:         token,
		claims:        claims,
	}, nil
}

// isAudience checks the audience
func (r userContext) isAudience(aud string) bool {
	if r.audience == aud {
		return true
	}

	return false
}

// getRoles returns a list of roles
func (r userContext) getRoles() string {
	return strings.Join(r.roles, ",")
}

// isExpired checks if the token has expired
func (r userContext) isExpired() bool {
	return r.expiresAt.Before(time.Now())
}

// isBearerToken checks if the token
func (r userContext) isBearer() bool {
	return r.bearerToken
}

// isCookie checks if it's by a cookie
func (r userContext) isCookie() bool {
	return !r.isBearer()
}

// String returns a string representation of the user context
func (r userContext) String() string {
	return fmt.Sprintf("user: %s, expires: %s, roles: %s", r.preferredName, r.expiresAt.String(), strings.Join(r.roles, ","))
}