Add endpoint for GETing AuthSession information for a user/realm tuple

Add a new `AuthSession` function `Authenticated()` which returns `true` if the
user has completed the auth process. This allows the caller to distinguish
between:
 - Never done any auth (404s)
 - In the process of doing auth (`Authenticated == false`)
 - Finished doing auth (`Authenticated == true`)

src/github.com/matrix-org/go-neb/api.go

@@ -263,3 +263,38 @@ func (h *getServiceHandler) OnIncomingRequest(req *http.Request) (interface{}, *
 		Config types.Service
 	}{srv.ServiceID(), srv.ServiceType(), srv}, nil
 }
+
+type getSessionHandler struct {
+	db *database.ServiceDB
+}
+
+func (h *getSessionHandler) OnIncomingRequest(req *http.Request) (interface{}, *errors.HTTPError) {
+	if req.Method != "GET" {
+		return nil, &errors.HTTPError{nil, "Unsupported Method", 405}
+	}
+	var body struct {
+		RealmID string
+		UserID  string
+	}
+	if err := json.NewDecoder(req.Body).Decode(&body); err != nil {
+		return nil, &errors.HTTPError{err, "Error parsing request JSON", 400}
+	}
+
+	if body.RealmID == "" || body.UserID == "" {
+		return nil, &errors.HTTPError{nil, `Must supply a "RealmID" and "UserID"`, 400}
+	}
+
+	session, err := h.db.LoadAuthSessionByUser(body.RealmID, body.UserID)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, &errors.HTTPError{err, `Session not found`, 404}
+		}
+		return nil, &errors.HTTPError{err, `Failed to load session`, 500}
+	}
+
+	return &struct {
+		ID            string
+		Authenticated bool
+		Session       types.AuthSession
+	}{session.ID(), session.Authenticated(), session}, nil
+}

src/github.com/matrix-org/go-neb/goneb.go

@@ -41,6 +41,7 @@ func main() {
 
 	http.Handle("/test", server.MakeJSONAPI(&heartbeatHandler{}))
 	http.Handle("/admin/getService", server.MakeJSONAPI(&getServiceHandler{db: db}))
+	http.Handle("/admin/getSession", server.MakeJSONAPI(&getSessionHandler{db: db}))
 	http.Handle("/admin/configureClient", server.MakeJSONAPI(&configureClientHandler{db: db, clients: clients}))
 	http.Handle("/admin/configureService", server.MakeJSONAPI(&configureServiceHandler{db: db, clients: clients}))
 	http.Handle("/admin/configureAuthRealm", server.MakeJSONAPI(&configureAuthRealmHandler{db: db}))

src/github.com/matrix-org/go-neb/realms/github/github.go

@@ -30,6 +30,11 @@ type GithubSession struct {
 	realmID string
 }
 
+// Authenticated returns true if the user has completed the auth process
+func (s *GithubSession) Authenticated() bool {
+	return s.AccessToken != ""
+}
+
 // UserID returns the user_id who authorised with Github
 func (s *GithubSession) UserID() string {
 	return s.userID

src/github.com/matrix-org/go-neb/realms/jira/jira.go

@@ -46,6 +46,11 @@ type JIRASession struct {
 	AccessSecret  string
 }
 
+// Authenticated returns true if the user has completed the auth process
+func (s *JIRASession) Authenticated() bool {
+	return s.AccessToken != "" && s.AccessSecret != ""
+}
+
 // UserID returns the ID of the user performing the authentication.
 func (s *JIRASession) UserID() string {
 	return s.userID

src/github.com/matrix-org/go-neb/types/types.go

@@ -123,4 +123,5 @@ type AuthSession interface {
 	ID() string
 	UserID() string
 	RealmID() string
+	Authenticated() bool
 }