authorization

go-jwt-tools

Golang authorization http middleware for Authorization headers

These are the important features on this package:

• User: The object representation of who is doing the request and its permissions.

type User struct {
	AuthorizationValue string
	IsDummy            bool
	Permissions        Permissions
	UserID             []string
}

type Permissions interface {
	// CheckPermission returns the given Permissions for a given product and object. Returns the special Permissions applied on that object if any, and a boolean indicating if the user has the requested Permission. NOTE: Special Permissions returned can be filtered by the specials argument).
	CheckPermission(product string, object string, permission Permission, specials ...string) ([]string, bool)
	// ValidGroups returns all the groups and its Permissions that have any Permission for the given product and object.
	ValidGroups(product string, object string, permission Permission) map[string]struct{}
	// Returns all groups of a given type
	GetGroups(groupType string) []string
	// GetAllGroups returns the group hierarchy
	GetAllGroups() map[string]struct{}
	// GetGroupsByTypes returns a map indexed by group types, containing the list of groups of that type
	GetGroupsByTypes() map[string][]string
	// GetParents returns all the parent groups of a given group.
	GetParents(group string) map[string]interface{}
}

• Parser: Who knows how to transform an authorization header into an User, this is what the different authorization techniques should implement.

type Parser interface {
	Parse(authHeader string) (*User, error)
}

• Middleware: A middleware is a wrap to a http.Handler

func(h http.Handler) http.Handler

This concrete middleware requires a Parser that will be used to transform the Authorization header from http.Request into an User, and then put in the request context. To retrieve the User from the context, use the function:

func UserFromContext(ctx context.Context) (*User, bool)

Implementations

Implementation details can be found in these subpackages:

jwt

In this implementation, the Authorization headers must be Bearers (auth0 or other).

The jwt parser can be instantiated from:

type ParserConfig struct {
	PublicKey        string  
	AdminGroup       string  
	DummyToken       string  
	IgnoreExpiration bool    
	MemberIDClaim    []string
	GroupsClaim      []string
}

cache

Has a Parser implementation that uses a lru cache where the key is the Authorization header and the value is the User, it basically caches the Parsing process. Recommended when the parsing process is heavy.

How to use

First instance the desired Parser implementation, for instance, if we want our endpoint to understand of jwt bearers:

jwtParserConfig := jwt.ParserConfig{
		AdminGroup:       "admin",
		PublicKey:        "myKey",
		DummyToken:       "dummyToken",
		IgnoreExpiration: false,
		GroupsClaim:      []string{"https://xtg.com/iam", "https://travelgatex.com/iam"},
		MemberIDClaim:    []string{"https://xtg.com/member_id", "https://travelgatex.com/member_id"},
	}

jwtParser := jwt.NewParser(jwtParserConfig)

Then, if we want a cache layer to cache the jwt parsing process we can wrap the jwtParser with a cache parser:

size := 100
ttl := time.Minute
c, _ := cache.New(size, ttl)
cacheParser := authcache.NewParser(jwtParser, c)

Now that we have built the desired parser cacheParser, instance the middleware and use it to wrap your service handler:

middleware := authorization.Middleware(cacheParser)

var serviceHandler http.Handler // omitted code
serviceHandler = middleware(serviceHandler)

http.Handle("/foo", serviceHandler)

Remember that in order to obtain the User, you must retrieve it from the context.Context using the func UserFromContext