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github.com/dgrijalva/jwt-go

package jwt

v3.2.0+incompatible
Latest Go to latest
Published: Mar 8, 2018 | License: MIT | Module: github.com/dgrijalva/jwt-go

Overview

Package jwt is a Go implementation of JSON Web Tokens: http://self-issued.info/docs/draft-jones-json-web-token.html

See README.md for more info.

Example (GetTokenViaHTTP)

Code:

// See func authHandler for an example auth handler that produces a token
res, err := http.PostForm(fmt.Sprintf("http://localhost:%v/authenticate", serverPort), url.Values{
	"user": {"test"},
	"pass": {"known"},
})
if err != nil {
	fatal(err)
}

if res.StatusCode != 200 {
	fmt.Println("Unexpected status code", res.StatusCode)
}

// Read the token out of the response body
buf := new(bytes.Buffer)
io.Copy(buf, res.Body)
res.Body.Close()
tokenString := strings.TrimSpace(buf.String())

// Parse the token
token, err := jwt.ParseWithClaims(tokenString, &CustomClaimsExample{}, func(token *jwt.Token) (interface{}, error) {
	// since we only use the one private key to sign the tokens,
	// we also only use its public counter part to verify
	return verifyKey, nil
})
fatal(err)

claims := token.Claims.(*CustomClaimsExample)
fmt.Println(claims.CustomerInfo.Name)

Output:

test
Example (UseTokenViaHTTP)

Code:

// Make a sample token
// In a real world situation, this token will have been acquired from
// some other API call (see Example_getTokenViaHTTP)
token, err := createToken("foo")
fatal(err)

// Make request.  See func restrictedHandler for example request processor
req, err := http.NewRequest("GET", fmt.Sprintf("http://localhost:%v/restricted", serverPort), nil)
fatal(err)
req.Header.Set("Authorization", fmt.Sprintf("Bearer %v", token))
res, err := http.DefaultClient.Do(req)
fatal(err)

// Read the response body
buf := new(bytes.Buffer)
io.Copy(buf, res.Body)
res.Body.Close()
fmt.Println(buf.String())

Output:

Welcome, foo

Index

Examples

Constants

const (
	ValidationErrorMalformed        uint32 = 1 << iota // Token is malformed
	ValidationErrorUnverifiable                        // Token could not be verified because of signing problems
	ValidationErrorSignatureInvalid                    // Signature validation failed

	// Standard Claim validation errors
	ValidationErrorAudience      // AUD validation failed
	ValidationErrorExpired       // EXP validation failed
	ValidationErrorIssuedAt      // IAT validation failed
	ValidationErrorIssuer        // ISS validation failed
	ValidationErrorNotValidYet   // NBF validation failed
	ValidationErrorId            // JTI validation failed
	ValidationErrorClaimsInvalid // Generic claims validation error
)

The errors that might occur when parsing and validating a token

const UnsafeAllowNoneSignatureType unsafeNoneMagicConstant = "none signing method allowed"

Variables

var (
	ErrNotECPublicKey  = errors.New("Key is not a valid ECDSA public key")
	ErrNotECPrivateKey = errors.New("Key is not a valid ECDSA private key")
)
var (
	ErrInvalidKey      = errors.New("key is invalid")
	ErrInvalidKeyType  = errors.New("key is of invalid type")
	ErrHashUnavailable = errors.New("the requested hash function is unavailable")
)

Error constants

var (
	ErrKeyMustBePEMEncoded = errors.New("Invalid Key: Key must be PEM encoded PKCS1 or PKCS8 private key")
	ErrNotRSAPrivateKey    = errors.New("Key is not a valid RSA private key")
	ErrNotRSAPublicKey     = errors.New("Key is not a valid RSA public key")
)
var (
	// Sadly this is missing from crypto/ecdsa compared to crypto/rsa
	ErrECDSAVerification = errors.New("crypto/ecdsa: verification error")
)
var NoneSignatureTypeDisallowedError error
var SigningMethodNone *signingMethodNone

Implements the none signing method. This is required by the spec but you probably should never use it.

var TimeFunc = time.Now

TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time). You can override it to use another time value. This is useful for testing or if your server uses a different time zone than your tokens.

func DecodeSegment

func DecodeSegment(seg string) ([]byte, error)

Decode JWT specific base64url encoding with padding stripped

func EncodeSegment

func EncodeSegment(seg []byte) string

Encode JWT specific base64url encoding with padding stripped

func ParseECPrivateKeyFromPEM

func ParseECPrivateKeyFromPEM(key []byte) (*ecdsa.PrivateKey, error)

Parse PEM encoded Elliptic Curve Private Key Structure

func ParseECPublicKeyFromPEM

func ParseECPublicKeyFromPEM(key []byte) (*ecdsa.PublicKey, error)

Parse PEM encoded PKCS1 or PKCS8 public key

func ParseRSAPrivateKeyFromPEM

func ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error)

Parse PEM encoded PKCS1 or PKCS8 private key

func ParseRSAPrivateKeyFromPEMWithPassword

func ParseRSAPrivateKeyFromPEMWithPassword(key []byte, password string) (*rsa.PrivateKey, error)

Parse PEM encoded PKCS1 or PKCS8 private key protected with password

func ParseRSAPublicKeyFromPEM

func ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error)

Parse PEM encoded PKCS1 or PKCS8 public key

func RegisterSigningMethod

func RegisterSigningMethod(alg string, f func() SigningMethod)

Register the "alg" name and a factory function for signing method. This is typically done during init() in the method's implementation

type Claims

type Claims interface {
	Valid() error
}

For a type to be a Claims object, it must just have a Valid method that determines if the token is invalid for any supported reason

type Keyfunc

type Keyfunc func(*Token) (interface{}, error)

Parse methods use this callback function to supply the key for verification. The function receives the parsed, but unverified Token. This allows you to use properties in the Header of the token (such as `kid`) to identify which key to use.

type MapClaims

type MapClaims map[string]interface{}

Claims type that uses the map[string]interface{} for JSON decoding This is the default claims type if you don't supply one

func (MapClaims) Valid

func (m MapClaims) Valid() error

Validates time based claims "exp, iat, nbf". There is no accounting for clock skew. As well, if any of the above claims are not in the token, it will still be considered a valid claim.

func (MapClaims) VerifyAudience

func (m MapClaims) VerifyAudience(cmp string, req bool) bool

Compares the aud claim against cmp. If required is false, this method will return true if the value matches or is unset

func (MapClaims) VerifyExpiresAt

func (m MapClaims) VerifyExpiresAt(cmp int64, req bool) bool

Compares the exp claim against cmp. If required is false, this method will return true if the value matches or is unset

func (MapClaims) VerifyIssuedAt

func (m MapClaims) VerifyIssuedAt(cmp int64, req bool) bool

Compares the iat claim against cmp. If required is false, this method will return true if the value matches or is unset

func (MapClaims) VerifyIssuer

func (m MapClaims) VerifyIssuer(cmp string, req bool) bool

Compares the iss claim against cmp. If required is false, this method will return true if the value matches or is unset

func (MapClaims) VerifyNotBefore

func (m MapClaims) VerifyNotBefore(cmp int64, req bool) bool

Compares the nbf claim against cmp. If required is false, this method will return true if the value matches or is unset

type Parser

type Parser struct {
	ValidMethods         []string // If populated, only these methods will be considered valid
	UseJSONNumber        bool     // Use JSON Number format in JSON decoder
	SkipClaimsValidation bool     // Skip claims validation during token parsing
}

func (*Parser) Parse

func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error)

Parse, validate, and return a token. keyFunc will receive the parsed token and should return the key for validating. If everything is kosher, err will be nil

func (*Parser) ParseUnverified

func (p *Parser) ParseUnverified(tokenString string, claims Claims) (token *Token, parts []string, err error)

WARNING: Don't use this method unless you know what you're doing

This method parses the token but doesn't validate the signature. It's only ever useful in cases where you know the signature is valid (because it has been checked previously in the stack) and you want to extract values from it.

func (*Parser) ParseWithClaims

func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error)

type SigningMethod

type SigningMethod interface {
	Verify(signingString, signature string, key interface{}) error // Returns nil if signature is valid
	Sign(signingString string, key interface{}) (string, error)    // Returns encoded signature or error
	Alg() string                                                   // returns the alg identifier for this method (example: 'HS256')
}

Implement SigningMethod to add new methods for signing or verifying tokens.

func GetSigningMethod

func GetSigningMethod(alg string) (method SigningMethod)

Get a signing method from an "alg" string

type SigningMethodECDSA

type SigningMethodECDSA struct {
	Name      string
	Hash      crypto.Hash
	KeySize   int
	CurveBits int
}

Implements the ECDSA family of signing methods signing methods Expects *ecdsa.PrivateKey for signing and *ecdsa.PublicKey for verification

var (
	SigningMethodES256 *SigningMethodECDSA
	SigningMethodES384 *SigningMethodECDSA
	SigningMethodES512 *SigningMethodECDSA
)

Specific instances for EC256 and company

func (*SigningMethodECDSA) Alg

func (m *SigningMethodECDSA) Alg() string

func (*SigningMethodECDSA) Sign

func (m *SigningMethodECDSA) Sign(signingString string, key interface{}) (string, error)

Implements the Sign method from SigningMethod For this signing method, key must be an ecdsa.PrivateKey struct

func (*SigningMethodECDSA) Verify

func (m *SigningMethodECDSA) Verify(signingString, signature string, key interface{}) error

Implements the Verify method from SigningMethod For this verify method, key must be an ecdsa.PublicKey struct

type SigningMethodHMAC

type SigningMethodHMAC struct {
	Name string
	Hash crypto.Hash
}

Implements the HMAC-SHA family of signing methods signing methods Expects key type of []byte for both signing and validation

var (
	SigningMethodHS256  *SigningMethodHMAC
	SigningMethodHS384  *SigningMethodHMAC
	SigningMethodHS512  *SigningMethodHMAC
	ErrSignatureInvalid = errors.New("signature is invalid")
)

Specific instances for HS256 and company

func (*SigningMethodHMAC) Alg

func (m *SigningMethodHMAC) Alg() string

func (*SigningMethodHMAC) Sign

func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) (string, error)

Implements the Sign method from SigningMethod for this signing method. Key must be []byte

func (*SigningMethodHMAC) Verify

func (m *SigningMethodHMAC) Verify(signingString, signature string, key interface{}) error

Verify the signature of HSXXX tokens. Returns nil if the signature is valid.

type SigningMethodRSA

type SigningMethodRSA struct {
	Name string
	Hash crypto.Hash
}

Implements the RSA family of signing methods signing methods Expects *rsa.PrivateKey for signing and *rsa.PublicKey for validation

var (
	SigningMethodRS256 *SigningMethodRSA
	SigningMethodRS384 *SigningMethodRSA
	SigningMethodRS512 *SigningMethodRSA
)

Specific instances for RS256 and company

func (*SigningMethodRSA) Alg

func (m *SigningMethodRSA) Alg() string

func (*SigningMethodRSA) Sign

func (m *SigningMethodRSA) Sign(signingString string, key interface{}) (string, error)

Implements the Sign method from SigningMethod For this signing method, must be an *rsa.PrivateKey structure.

func (*SigningMethodRSA) Verify

func (m *SigningMethodRSA) Verify(signingString, signature string, key interface{}) error

Implements the Verify method from SigningMethod For this signing method, must be an *rsa.PublicKey structure.

type SigningMethodRSAPSS

type SigningMethodRSAPSS struct {
	*SigningMethodRSA
	Options *rsa.PSSOptions
}

Implements the RSAPSS family of signing methods signing methods

var (
	SigningMethodPS256 *SigningMethodRSAPSS
	SigningMethodPS384 *SigningMethodRSAPSS
	SigningMethodPS512 *SigningMethodRSAPSS
)

Specific instances for RS/PS and company

func (*SigningMethodRSAPSS) Sign

func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error)

Implements the Sign method from SigningMethod For this signing method, key must be an rsa.PrivateKey struct

func (*SigningMethodRSAPSS) Verify

func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error

Implements the Verify method from SigningMethod For this verify method, key must be an rsa.PublicKey struct

type StandardClaims

type StandardClaims struct {
	Audience  string `json:"aud,omitempty"`
	ExpiresAt int64  `json:"exp,omitempty"`
	Id        string `json:"jti,omitempty"`
	IssuedAt  int64  `json:"iat,omitempty"`
	Issuer    string `json:"iss,omitempty"`
	NotBefore int64  `json:"nbf,omitempty"`
	Subject   string `json:"sub,omitempty"`
}

Structured version of Claims Section, as referenced at https://tools.ietf.org/html/rfc7519#section-4.1 See examples for how to use this with your own claim types

func (StandardClaims) Valid

func (c StandardClaims) Valid() error

Validates time based claims "exp, iat, nbf". There is no accounting for clock skew. As well, if any of the above claims are not in the token, it will still be considered a valid claim.

func (*StandardClaims) VerifyAudience

func (c *StandardClaims) VerifyAudience(cmp string, req bool) bool

Compares the aud claim against cmp. If required is false, this method will return true if the value matches or is unset

func (*StandardClaims) VerifyExpiresAt

func (c *StandardClaims) VerifyExpiresAt(cmp int64, req bool) bool

Compares the exp claim against cmp. If required is false, this method will return true if the value matches or is unset

func (*StandardClaims) VerifyIssuedAt

func (c *StandardClaims) VerifyIssuedAt(cmp int64, req bool) bool

Compares the iat claim against cmp. If required is false, this method will return true if the value matches or is unset

func (*StandardClaims) VerifyIssuer

func (c *StandardClaims) VerifyIssuer(cmp string, req bool) bool

Compares the iss claim against cmp. If required is false, this method will return true if the value matches or is unset

func (*StandardClaims) VerifyNotBefore

func (c *StandardClaims) VerifyNotBefore(cmp int64, req bool) bool

Compares the nbf claim against cmp. If required is false, this method will return true if the value matches or is unset

type Token

type Token struct {
	Raw       string                 // The raw token.  Populated when you Parse a token
	Method    SigningMethod          // The signing method used or to be used
	Header    map[string]interface{} // The first segment of the token
	Claims    Claims                 // The second segment of the token
	Signature string                 // The third segment of the token.  Populated when you Parse a token
	Valid     bool                   // Is the token valid?  Populated when you Parse/Verify a token
}

A JWT Token. Different fields will be used depending on whether you're creating or parsing/verifying a token.

func New

func New(method SigningMethod) *Token

Create a new Token. Takes a signing method

Example (Hmac)

Example creating, signing, and encoding a JWT token using the HMAC signing method

Code:

// Create a new token object, specifying signing method and the claims
// you would like it to contain.
token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
	"foo": "bar",
	"nbf": time.Date(2015, 10, 10, 12, 0, 0, 0, time.UTC).Unix(),
})

// Sign and get the complete encoded token as a string using the secret
tokenString, err := token.SignedString(hmacSampleSecret)

fmt.Println(tokenString, err)

Output:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJuYmYiOjE0NDQ0Nzg0MDB9.u1riaD1rW97opCoAuRCTy4w58Br-Zk-bh7vLiRIsrpU <nil>

func NewWithClaims

func NewWithClaims(method SigningMethod, claims Claims) *Token
Example (CustomClaimsType)

Example creating a token using a custom claims type. The StandardClaim is embedded in the custom type to allow for easy encoding, parsing and validation of standard claims.

Code:

mySigningKey := []byte("AllYourBase")

type MyCustomClaims struct {
	Foo string `json:"foo"`
	jwt.StandardClaims
}

// Create the Claims
claims := MyCustomClaims{
	"bar",
	jwt.StandardClaims{
		ExpiresAt: 15000,
		Issuer:    "test",
	},
}

token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
ss, err := token.SignedString(mySigningKey)
fmt.Printf("%v %v", ss, err)

Output:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c <nil>
Example (StandardClaims)

Example (atypical) using the StandardClaims type by itself to parse a token. The StandardClaims type is designed to be embedded into your custom types to provide standard validation features. You can use it alone, but there's no way to retrieve other fields after parsing. See the CustomClaimsType example for intended usage.

Code:

mySigningKey := []byte("AllYourBase")

// Create the Claims
claims := &jwt.StandardClaims{
	ExpiresAt: 15000,
	Issuer:    "test",
}

token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
ss, err := token.SignedString(mySigningKey)
fmt.Printf("%v %v", ss, err)

Output:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.QsODzZu3lUZMVdhbO76u3Jv02iYCvEHcYVUI1kOWEU0 <nil>

func Parse

func Parse(tokenString string, keyFunc Keyfunc) (*Token, error)

Parse, validate, and return a token. keyFunc will receive the parsed token and should return the key for validating. If everything is kosher, err will be nil

Example (ErrorChecking)

An example of parsing the error types using bitfield checks

Code:

// Token from another example.  This token is expired
var tokenString = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c"

token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
	return []byte("AllYourBase"), nil
})

if token.Valid {
	fmt.Println("You look nice today")
} else if ve, ok := err.(*jwt.ValidationError); ok {
	if ve.Errors&jwt.ValidationErrorMalformed != 0 {
		fmt.Println("That's not even a token")
	} else if ve.Errors&(jwt.ValidationErrorExpired|jwt.ValidationErrorNotValidYet) != 0 {
		// Token is either expired or not active yet
		fmt.Println("Timing is everything")
	} else {
		fmt.Println("Couldn't handle this token:", err)
	}
} else {
	fmt.Println("Couldn't handle this token:", err)
}

Output:

Timing is everything
Example (Hmac)

Example parsing and validating a token using the HMAC signing method

Code:

// sample token string taken from the New example
tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJuYmYiOjE0NDQ0Nzg0MDB9.u1riaD1rW97opCoAuRCTy4w58Br-Zk-bh7vLiRIsrpU"

// Parse takes the token string and a function for looking up the key. The latter is especially
// useful if you use multiple keys for your application.  The standard is to use 'kid' in the
// head of the token to identify which key to use, but the parsed token (head and claims) is provided
// to the callback, providing flexibility.
token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
	// Don't forget to validate the alg is what you expect:
	if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
		return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
	}

	// hmacSampleSecret is a []byte containing your secret, e.g. []byte("my_secret_key")
	return hmacSampleSecret, nil
})

if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
	fmt.Println(claims["foo"], claims["nbf"])
} else {
	fmt.Println(err)
}

Output:

bar 1.4444784e+09

func ParseWithClaims

func ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error)
Example (CustomClaimsType)

Example creating a token using a custom claims type. The StandardClaim is embedded in the custom type to allow for easy encoding, parsing and validation of standard claims.

Code:

tokenString := "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c"

type MyCustomClaims struct {
	Foo string `json:"foo"`
	jwt.StandardClaims
}

// sample token is expired.  override time so it parses as valid
at(time.Unix(0, 0), func() {
	token, err := jwt.ParseWithClaims(tokenString, &MyCustomClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte("AllYourBase"), nil
	})

	if claims, ok := token.Claims.(*MyCustomClaims); ok && token.Valid {
		fmt.Printf("%v %v", claims.Foo, claims.StandardClaims.ExpiresAt)
	} else {
		fmt.Println(err)
	}
})

Output:

bar 15000

func (*Token) SignedString

func (t *Token) SignedString(key interface{}) (string, error)

Get the complete, signed token

func (*Token) SigningString

func (t *Token) SigningString() (string, error)

Generate the signing string. This is the most expensive part of the whole deal. Unless you need this for something special, just go straight for the SignedString.

type ValidationError

type ValidationError struct {
	Inner  error  // stores the error returned by external dependencies, i.e.: KeyFunc
	Errors uint32 // bitfield.  see ValidationError... constants
	// contains filtered or unexported fields
}

The error from Parse if token is not valid

func NewValidationError

func NewValidationError(errorText string, errorFlags uint32) *ValidationError

Helper for constructing a ValidationError with a string error message

func (ValidationError) Error

func (e ValidationError) Error() string

Validation error is an error type

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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