Files
SciMesh/users/internal/auth/jwt.go
T
2026-07-26 14:38:24 +03:00

68 lines
2.0 KiB
Go

package auth
import (
"fmt"
"time"
"github.com/golang-jwt/jwt/v5"
"github.com/google/uuid"
"github.com/emil28092005/SciMesh/users/internal/domain"
)
// Claims is the payload of a signed token. Subject (from RegisteredClaims) is
// the user id — it becomes the coordinator's jobs.owner_id; Role drives
// authorization. Both services verify this token locally with the shared HS256
// secret, so no runtime call back to the userservice is ever needed.
type Claims struct {
Role domain.Role `json:"role"`
jwt.RegisteredClaims
}
// Issuer signs and verifies tokens with a shared HS256 secret.
type Issuer struct {
secret []byte
ttl time.Duration
now func() time.Time
}
// NewIssuer builds an Issuer. now defaults to time.Now when nil; tests inject a
// fixed clock to make expiry deterministic.
func NewIssuer(secret string, ttl time.Duration, now func() time.Time) Issuer {
if now == nil {
now = time.Now
}
return Issuer{secret: []byte(secret), ttl: ttl, now: now}
}
// Issue returns a signed token for the user, valid for the configured TTL.
func (i Issuer) Issue(userID uuid.UUID, role domain.Role) (string, error) {
now := i.now()
claims := Claims{
Role: role,
RegisteredClaims: jwt.RegisteredClaims{
Subject: userID.String(),
IssuedAt: jwt.NewNumericDate(now),
ExpiresAt: jwt.NewNumericDate(now.Add(i.ttl)),
},
}
return jwt.NewWithClaims(jwt.SigningMethodHS256, claims).SignedString(i.secret)
}
// Verify checks the signature and expiry and returns the claims. It pins the
// algorithm to HMAC, rejecting a token that asks for "none" or an RS256 public
// key — the classic algorithm-substitution attack against naive verifiers.
func (i Issuer) Verify(token string) (*Claims, error) {
var claims Claims
_, err := jwt.ParseWithClaims(token, &claims, func(t *jwt.Token) (any, error) {
if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
return nil, fmt.Errorf("unexpected signing method: %v", t.Header["alg"])
}
return i.secret, nil
})
if err != nil {
return nil, err
}
return &claims, nil
}