Roughing in JWT-based authentication.

Todo: Actually utilize this stuff somewhere.

.travis.yml

@@ -6,4 +6,7 @@ addons:
 go: 1.3
 
 before_script:
-  - psql -c 'create database bactdbtest;' -U postgres
+  - psql -c 'CREATE DATABASE bactdbtest;' -U postgres
+  - openssl genrsa -out keys/app.rsa 2048
+  - openssl rsa -in keys/app.rsa -pubout > keys/app.rsa.pub
+

api/auth.go

@@ -0,0 +1,146 @@
+package api
+
+import (
+	"errors"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/dgrijalva/jwt-go"
+)
+
+const (
+	privKeyPath = "keys/app.rsa"     // openssl genrsa -out app.rsa keysize
+	pubKeyPath  = "keys/app.rsa.pub" // openssl rsa -in app.rsa -pubout > app.rsa.pub
+	tokenName   = "AccessToken"
+)
+
+var (
+	verifyKey, signKey    []byte
+	errWhileSigningToken  = errors.New("error while signing token")
+	errPleaseLogIn        = errors.New("please log in")
+	errWhileParsingCookie = errors.New("error while parsing cookie")
+	errTokenExpired       = errors.New("token expired")
+	errGenericError       = errors.New("generic error")
+)
+
+func init() {
+	var err error
+
+	signKey, err = ioutil.ReadFile(privKeyPath)
+
+	if err != nil {
+		// Before exploding, check up one level...
+		signKey, err = ioutil.ReadFile("../" + privKeyPath)
+		if err != nil {
+			log.Fatalf("Error reading private key: ", err)
+			return
+		}
+	}
+
+	verifyKey, err = ioutil.ReadFile(pubKeyPath)
+	if err != nil {
+		// Before exploding, check up one level...
+		verifyKey, err = ioutil.ReadFile("../" + pubKeyPath)
+		if err != nil {
+			log.Fatalf("Error reading public key: ", err)
+			return
+		}
+	}
+}
+
+func serveToken(w http.ResponseWriter, r *http.Request) error {
+	t := jwt.New(jwt.GetSigningMethod("RS256"))
+
+	// Set our claims
+	t.Claims["AccessToken"] = "level1"
+	t.Claims["CustomUserInfo"] = struct {
+		Name string
+		Kind string
+	}{"mrdillon", "human"}
+
+	// Set the expire time
+	// See http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-20#section-4.1.4
+	t.Claims["exp"] = time.Now().Add(time.Minute * 1).Unix()
+	tokenString, err := t.SignedString(signKey)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return errWhileSigningToken
+	}
+
+	http.SetCookie(w, &http.Cookie{
+		Name:       tokenName,
+		Value:      tokenString,
+		Path:       "/",
+		RawExpires: "0",
+	})
+
+	return writeJSON(w, Message{"success"})
+}
+
+type authHandler func(http.ResponseWriter, *http.Request) error
+
+// Only accessible with a valid token
+func (h authHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Even though writeJSON sets the content type, we need to set it here because
+	// calls to WriteHeader write out the entire header.
+	w.Header().Set("content-type", "application/json; charset=utf-8")
+	tokenCookie, err := r.Cookie(tokenName)
+	switch {
+	case err == http.ErrNoCookie:
+		w.WriteHeader(http.StatusUnauthorized)
+		writeJSON(w, Error{errPleaseLogIn})
+		return
+	case err != nil:
+		w.WriteHeader(http.StatusInternalServerError)
+		writeJSON(w, Error{errWhileParsingCookie})
+		return
+	}
+
+	if tokenCookie.Value == "" {
+		w.WriteHeader(http.StatusUnauthorized)
+		writeJSON(w, Error{errPleaseLogIn})
+		return
+	}
+
+	// Validate the token
+	token, err := jwt.Parse(tokenCookie.Value, func(token *jwt.Token) (interface{}, error) {
+		return verifyKey, nil
+	})
+
+	// Branch out into the possible error from signing
+	switch err.(type) {
+	case nil: // No error
+		if !token.Valid { // But may still be invalid
+			w.WriteHeader(http.StatusUnauthorized)
+			writeJSON(w, Error{errPleaseLogIn})
+			return
+		}
+	case *jwt.ValidationError: // Something was wrong during the validation
+		vErr := err.(*jwt.ValidationError)
+		switch vErr.Errors {
+		case jwt.ValidationErrorExpired:
+			w.WriteHeader(http.StatusUnauthorized)
+			writeJSON(w, Error{errTokenExpired})
+			return
+		default:
+			w.WriteHeader(http.StatusInternalServerError)
+			writeJSON(w, Error{errGenericError})
+			return
+		}
+	default: // Something else went wrong
+		w.WriteHeader(http.StatusInternalServerError)
+		writeJSON(w, Error{errGenericError})
+		return
+	}
+	hErr := h(w, r)
+	if hErr != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		writeJSON(w, Error{hErr})
+	}
+}
+
+func restrictedHandler(w http.ResponseWriter, r *http.Request) error {
+	return writeJSON(w, Message{"great success"})
+}

api/handler.go

@@ -1,8 +1,6 @@
 package api
 
 import (
-	"fmt"
-	"log"
 	"net/http"
 
 	"github.com/gorilla/mux"
@@ -71,6 +69,9 @@ func Handler() *mux.Router {
 	m.Get(router.UpdateMeasurement).Handler(handler(serveUpdateMeasurement))
 	m.Get(router.DeleteMeasurement).Handler(handler(serveDeleteMeasurement))
 
+	m.Get(router.GetToken).Handler(handler(serveToken))
+	m.Get(router.Restricted).Handler(authHandler(restrictedHandler))
+
 	return m
 }
 
@@ -80,7 +81,6 @@ func (h handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	err := h(w, r)
 	if err != nil {
 		w.WriteHeader(http.StatusInternalServerError)
-		fmt.Fprintf(w, "error: %s", err)
-		log.Println(err)
+		writeJSON(w, Error{err})
 	}
 }

api/helpers.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"encoding/json"
+	"log"
 	"net/http"
 )
 
@@ -17,3 +18,20 @@ func writeJSON(w http.ResponseWriter, v interface{}) error {
 	_, err = w.Write(data)
 	return err
 }
+
+// Message is for returning simple message payloads to the user
+type Message struct {
+	Message string `json:"message"`
+}
+
+// Error is for returning simple error payloads to the user, as well as logging
+type Error struct {
+	Error error
+}
+
+func (e Error) MarshalJSON() ([]byte, error) {
+	log.Println(e.Error)
+	return json.Marshal(struct {
+		Error string `json:"error"`
+	}{e.Error.Error()})
+}

datastore/db.go

@@ -43,10 +43,6 @@ func Create(path string) {
 	if err != nil {
 		log.Fatal("Error initializing migrations: ", err)
 	}
-
-	pwd, err := os.Getwd()
-	log.Print("current path: ", pwd)
-
 	err = migrator.Migrate()
 	if err != nil {
 		log.Fatal("Error applying migrations: ", err)

keys/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

router/api.go

@@ -66,5 +66,9 @@ func API() *mux.Router {
 	m.Path("/measurements/{Id:.+}").Methods("PUT").Name(UpdateMeasurement)
 	m.Path("/measurements/{Id:.+}").Methods("DELETE").Name(DeleteMeasurement)
 
+	// Authentication
+	m.Path("/token/").Methods("GET").Name(GetToken)
+	m.Path("/restricted/").Methods("GET").Name(Restricted)
+
 	return m
 }

router/routes.go

@@ -52,4 +52,7 @@ const (
 	Measurements      = "measurements:list"
 	UpdateMeasurement = "measurements:update"
 	DeleteMeasurement = "measurements:delete"
+
+	GetToken   = "token:get"
+	Restricted = "restricted:get"
 )