mirror of https://github.com/golang-jwt/jwt.git
105 lines
2.3 KiB
Go
105 lines
2.3 KiB
Go
package jwt
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import (
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"encoding/base64"
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"encoding/json"
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"errors"
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"net/http"
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"strings"
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"time"
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)
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// A JWT Token
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type Token struct {
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Header map[string]interface{}
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Claims map[string]interface{}
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Method SigningMethod
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Signature string
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Valid bool
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}
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// Parse, validate, and return a token.
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// keyFunc will receive the parsed token and should return the key for validating.
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// If everything is kosher, err will be nil
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func Parse(tokenString string, keyFunc func(*Token) ([]byte, error)) (token *Token, err error) {
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parts := strings.Split(tokenString, ".")
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if len(parts) == 3 {
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token = new(Token)
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// parse Header
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var headerBytes []byte
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if headerBytes, err = DecodeSegment(parts[0]); err != nil {
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return
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}
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if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
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return
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}
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// parse Claims
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var claimBytes []byte
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if claimBytes, err = DecodeSegment(parts[1]); err != nil {
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return
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}
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if err = json.Unmarshal(claimBytes, &token.Claims); err != nil {
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return
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}
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// Lookup signature method
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if method, ok := token.Header["alg"].(string); ok {
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if token.Method, err = GetSigningMethod(method); err != nil {
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return
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}
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} else {
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err = errors.New("Signing method (alg) is unspecified.")
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return
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}
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// Check expiry times
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if exp, ok := token.Claims["exp"].(float64); ok {
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if time.Now().Unix() > int64(exp) {
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err = errors.New("Token is expired")
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}
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}
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// Lookup key
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var key []byte
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if key, err = keyFunc(token); err != nil {
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return
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}
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// Perform validation
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if err = token.Method.Verify(strings.Join(parts[0:2], "."), parts[2], key); err == nil {
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token.Valid = true
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}
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} else {
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err = errors.New("Token contains an invalid number of segments")
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}
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return
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}
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func ParseFromRequest(req *http.Request, keyFunc func(*Token) ([]byte, error)) (token *Token, err error) {
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// Look for an Authorization header
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if ah := req.Header.Get("Authorization"); ah != "" {
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// Should be a bearer token
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if len(ah) > 6 && strings.ToUpper(ah[0:6]) == "BEARER" {
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return Parse(ah[7:], keyFunc)
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}
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}
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return nil, errors.New("No token present in request.")
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}
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func DecodeSegment(seg string) ([]byte, error) {
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// len % 4
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switch len(seg) % 4 {
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case 2:
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seg = seg + "=="
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case 3:
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seg = seg + "==="
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}
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return base64.URLEncoding.DecodeString(seg)
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}
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