timoth-y/kicksware-api

package rest

import (
    "encoding/json"
    "errors"
    "fmt"
    "net/http"
    "net/url"

    "github.com/golang-jwt/jwt/v4"
    "github.com/golang-jwt/jwt/v4/request"
    "github.com/golang/glog"

    "go.kicksware.com/api/shared/core"
)

var (
    ErrInvalidTokenClaims = errors.New("invalid token claims")
    GuestRole = "gst"
)

type authClaims struct {
    UniqueID  string `json:"nameid,omitempty"`
    Username  string `json:"unique_name,omitempty"`
    Email     string `json:"sub,omitempty"`
    Role      string `json:"role,omitempty"`
}

type AuthMiddleware struct {
    service core.AuthService
}


func NewAuthMiddleware(service core.AuthService) *AuthMiddleware {
    return &AuthMiddleware{
        service,
    }
}

func (m *AuthMiddleware) Authenticator(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        token, err := m.getRequestToken(r); if err != nil {
            http.Error(w, err.Error(), http.StatusUnauthorized)
            glog.Errorln(err)
            glog.Errorln(token.Raw)
            glog.Errorln(token.Claims)
            return
        }

        if token == nil || !token.Valid {
            http.Error(w, ErrInvalidTokenClaims.Error(), http.StatusInternalServerError)
            glog.Errorln(err)
            return
        }

        // Token is authenticated, pass it through
        next.ServeHTTP(w, r)
    })
}

func (m *AuthMiddleware) Authorizer(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        token, err := m.getRequestToken(r); if err != nil {
            http.Error(w, err.Error(), http.StatusUnauthorized)
            glog.Errorln(err)
            return
        }

        claims, err := getClaims(token); if err != nil {
            http.Error(w, ErrInvalidTokenClaims.Error(), http.StatusInternalServerError)
            glog.Errorln(err)
            return
        }
        if claims != nil && claims.Role != GuestRole {
            r.URL.User = url.UserPassword(claims.UniqueID, token.Raw)
        } else {
            http.Error(w, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
            fmt.Println()
            return
        }

        next.ServeHTTP(w, r)
    })
}

func (m *AuthMiddleware) UserSetter(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        token, err := m.getRequestToken(r); if err != nil {
            http.Error(w, err.Error(), http.StatusUnauthorized)
            glog.Errorln(err)
            return
        }

        if claims, err := getClaims(token); err == nil && claims != nil && claims.Role != GuestRole {
            r.URL.User = url.UserPassword(claims.UniqueID, token.Raw)
        } else {
            r.URL.User = nil
        }

        next.ServeHTTP(w, r)
    })
}

func (m *AuthMiddleware) getRequestToken(r *http.Request) (token *jwt.Token, err error) {
    token, err = request.ParseFromRequest(r, request.OAuth2Extractor, func(token *jwt.Token) (interface{}, error) {
        if _, ok := token.Method.(*jwt.SigningMethodRSA); ok {
            return m.service.PublicKey(), nil
        }
        return nil, fmt.Errorf("authenticator: unexpected signing method: %q", token.Header["alg"])
    })
    return
}

func getClaims(token *jwt.Token) (*authClaims, error) {
    payload, err := json.Marshal(token.Claims); if err != nil {
        return nil, err
    }
    claims := &authClaims{}

    if err = json.Unmarshal(payload, claims); err != nil {
        return nil, err
    }
    return claims, nil
}