README
¶
A go (or 'golang' for search engine friendliness) implementation of JSON Web Tokens
2.0.0 is coming!
There are a couple open pull requests that contain breaking changes I believe are essential for moving this project forward. We will try to make upgrading as painless as possible (and the 1.x.x versions will remain available). If you believe this will effect you, please review the open pull requests and comment as soon as possible. I'm planning to land these changes Friday, Aug 22, 2014.
The changes are very small modifications to the API, but in keeping with the spirit of semantic versioning, I'm taking any breaking change seriously.
What the heck is a JWT?
In short, it's a signed JSON object that does something useful (for example, authentication). It's commonly used for Bearer tokens in Oauth 2. A token is made of three parts, separated by .'s. The first two parts are JSON objects, that have been base64url encoded. The last part is the signature, encoded the same way.
The first part is called the header. It contains the necessary information for verifying the last part, the signature. For example, which encryption method was used for signing and what key was used.
The part in the middle is the interesting bit. It's called the Claims and contains the actual stuff you care about. Refer to the RFC for information about reserved keys and the proper way to add your own.
What's in the box?
This library supports the parsing and verification as well as the generation and signing of JWTs. Current supported signing algorithms are RSA256 and HMAC SHA256, though hooks are present for adding your own.
Parse and Verify
Parsing and verifying tokens is pretty straight forward. You pass in the token and a function for looking up the key. This is done as a callback since you may need to parse the token to find out what signing method and key was used.
token, err := jwt.Parse(myToken, func(token *jwt.Token) ([]byte, error) {
return myLookupKey(token.Header["kid"])
})
if err == nil && token.Valid {
deliverGoodness("!")
} else {
deliverUtterRejection(":(")
}
Create a token
// Create the token
token := jwt.New(jwt.GetSigningMethod("HS256"))
// Set some claims
token.Claims["foo"] = "bar"
token.Claims["exp"] = time.Now().Add(time.Hour * 72).Unix()
// Sign and get the complete encoded token as a string
tokenString, err := token.SignedString(mySigningKey)
Project Status & Versioning
This library is considered production ready. Feedback and feature requests are appreciated. The API should be considered stable. There should be very few backwards-incompatible changes outside of major version updates (and only with good reason).
This project uses Semantic Versioning 2.0.0. Accepted pull requests will land on master. Periodically, versions will be tagged from master. You can find all the releases on the project releases page.
More
Documentation can be found on godoc.org.
The command line utility included in this project (cmd/jwt) provides a straightforward example of token creation and parsing as well as a useful tool for debugging your own integration. For a more http centric example, see this gist.
Documentation
¶
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.
Index ¶
Constants ¶
const ( ValidationErrorMalformed uint32 = 1 << iota // Token is malformed ValidationErrorUnverifiable // Token could not be verified because of signing problems ValidationErrorSignatureInvalid // Signature validation failed ValidationErrorExpired // Exp validation failed ValidationErrorNotValidYet // NBF validation failed )
The errors that might occur when parsing and validating a token
Variables ¶
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.
Functions ¶
func DecodeSegment ¶
Decode JWT specific base64url encoding with padding stripped
func EncodeSegment ¶
Encode JWT specific base64url encoding with padding stripped
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
Types ¶
type Keyfunc ¶
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 propries in the Header of the token (such as `kid`) to identify which key to use.
type SigningMethod ¶
type SigningMethod interface {
Verify(signingString, signature string, key []byte) error
Sign(signingString string, key []byte) (string, error)
Alg() string
}
Signing method
func GetSigningMethod ¶
func GetSigningMethod(alg string) (method SigningMethod)
Get a signing method from an "alg" string
type SigningMethodHS256 ¶
type SigningMethodHS256 struct{}
func (*SigningMethodHS256) Alg ¶
func (m *SigningMethodHS256) Alg() string
type SigningMethodRS256 ¶
type SigningMethodRS256 struct{}
func (*SigningMethodRS256) Alg ¶
func (m *SigningMethodRS256) Alg() string
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 map[string]interface{} // 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 Parse ¶
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 ParseFromRequest ¶
Try to find the token in an http.Request. This method will call ParseMultipartForm if there's no token in the header. Currently, it looks in the Authorization header as well as looking for an 'access_token' request parameter in req.Form.
func (*Token) SignedString ¶
Get the complete, signed token
func (*Token) SigningString ¶
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 {
Errors uint32 // bitfield. see ValidationError... constants
// contains filtered or unexported fields
}
The error from Parse if token is not valid
func (ValidationError) Error ¶
func (e ValidationError) Error() string
Validation error is an error type
Source Files
Directories