signing_method.go raw

   1  package jwt
   2  
   3  import (
   4  	"sync"
   5  )
   6  
   7  var signingMethods = map[string]func() SigningMethod{}
   8  var signingMethodLock = new(sync.RWMutex)
   9  
  10  // SigningMethod can be used add new methods for signing or verifying tokens.
  11  type SigningMethod interface {
  12  	Verify(signingString, signature string, key interface{}) error // Returns nil if signature is valid
  13  	Sign(signingString string, key interface{}) (string, error)    // Returns encoded signature or error
  14  	Alg() string                                                   // returns the alg identifier for this method (example: 'HS256')
  15  }
  16  
  17  // RegisterSigningMethod registers the "alg" name and a factory function for signing method.
  18  // This is typically done during init() in the method's implementation
  19  func RegisterSigningMethod(alg string, f func() SigningMethod) {
  20  	signingMethodLock.Lock()
  21  	defer signingMethodLock.Unlock()
  22  
  23  	signingMethods[alg] = f
  24  }
  25  
  26  // GetSigningMethod retrieves a signing method from an "alg" string
  27  func GetSigningMethod(alg string) (method SigningMethod) {
  28  	signingMethodLock.RLock()
  29  	defer signingMethodLock.RUnlock()
  30  
  31  	if methodF, ok := signingMethods[alg]; ok {
  32  		method = methodF()
  33  	}
  34  	return
  35  }
  36  
  37  // GetAlgorithms returns a list of registered "alg" names
  38  func GetAlgorithms() (algs []string) {
  39  	signingMethodLock.RLock()
  40  	defer signingMethodLock.RUnlock()
  41  
  42  	for alg := range signingMethods {
  43  		algs = append(algs, alg)
  44  	}
  45  	return
  46  }
  47