signing_method.go

Documentation: github.com/golang-jwt/jwt/v5

     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. It
    11  // takes a decoded signature as an input in the Verify function and produces a
    12  // signature in Sign. The signature is then usually base64 encoded as part of a
    13  // JWT.
    14  type SigningMethod interface {
    15  	Verify(signingString string, sig []byte, key interface{}) error // Returns nil if signature is valid
    16  	Sign(signingString string, key interface{}) ([]byte, error)     // Returns signature or error
    17  	Alg() string                                                    // returns the alg identifier for this method (example: 'HS256')
    18  }
    19  
    20  // RegisterSigningMethod registers the "alg" name and a factory function for signing method.
    21  // This is typically done during init() in the method's implementation
    22  func RegisterSigningMethod(alg string, f func() SigningMethod) {
    23  	signingMethodLock.Lock()
    24  	defer signingMethodLock.Unlock()
    25  
    26  	signingMethods[alg] = f
    27  }
    28  
    29  // GetSigningMethod retrieves a signing method from an "alg" string
    30  func GetSigningMethod(alg string) (method SigningMethod) {
    31  	signingMethodLock.RLock()
    32  	defer signingMethodLock.RUnlock()
    33  
    34  	if methodF, ok := signingMethods[alg]; ok {
    35  		method = methodF()
    36  	}
    37  	return
    38  }
    39  
    40  // GetAlgorithms returns a list of registered "alg" names
    41  func GetAlgorithms() (algs []string) {
    42  	signingMethodLock.RLock()
    43  	defer signingMethodLock.RUnlock()
    44  
    45  	for alg := range signingMethods {
    46  		algs = append(algs, alg)
    47  	}
    48  	return
    49  }
    50
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