Add register.available method

STATUS.md

@@ -8,6 +8,7 @@ Implemented from [Client-Server API](https://matrix.org/docs/spec/client_server/
 - [x] [5.4.4 POST /_matrix/client/r0/logout/all](https://matrix.org/docs/spec/client_server/latest#post-matrix-client-r0-logout-all)
 - [x] [5.5.1 POST /_matrix/client/r0/register](https://matrix.org/docs/spec/client_server/r0.5.0#post-matrix-client-r0-register)
 - [x] [5.5.4 POST /_matrix/client/r0/account/password](https://matrix.org/docs/spec/client_server/latest#post-matrix-client-r0-account-password)
+- [x] [5.5.8 GET /_matrix/client/r0/register/available](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-register-available)
 - [x] [5.7.1 GET /_matrix/client/r0/account/whoami](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-account-whoami)
 - [x] [6.1 GET /_matrix/client/r0/capabilities](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-capabilities)
 - [x] [10.4.1 GET /_matrix/client/r0/joined_rooms](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-joined-rooms)

internal/backend.go

@@ -12,6 +12,7 @@ type Backend interface {
 	Register(username, password, device string) (user User, token string, err *models.ApiError)
 	Login(username, password, device string) (user User, token string, err *models.ApiError)
 	GetUserByToken(token string) (user User)
+	GetUserByName(userName string) User
 	GetRoomByID(id string) Room
 	Sync(token string, request sync.SyncRequest) (response *sync.SyncReply, err *models.ApiError)
 }

internal/backends/memory/backend.go

@@ -100,3 +100,14 @@ func (backend *Backend) GetRoomByID(id string) internal.Room {
 
 	return nil
 }
+
+func (backend *Backend) GetUserByName(userName string) internal.User {
+	backend.mutex.Lock()
+	defer backend.mutex.Unlock()
+
+	if user, exists := backend.data[userName]; exists {
+		return user
+	}
+
+	return nil
+}

internal/backends/memory/backend_test.go

@@ -113,3 +113,26 @@ func TestGetRoomByID(t *testing.T) {
 	room = backend.GetRoomByID("worng id")
 	assert.Nil(t, room)
 }
+
+func TestGetUserByName(t *testing.T) {
+	backend := NewBackend("localhost")
+
+	var (
+		userName = "user"
+	)
+
+	user, token, err := backend.Register(userName, "", "")
+	assert.Nil(t, err)
+	assert.NotNil(t, user)
+	assert.NotEmpty(t, token)
+
+	t.Run("Test picking user with username", func(_ *testing.T) {
+		user2 := backend.GetUserByName(userName)
+		assert.Equal(t, user, user2)
+	})
+
+	t.Run("Test picking user with wrong username", func(_ *testing.T) {
+		user2 := backend.GetUserByName("wrong username")
+		assert.Nil(t, user2)
+	})
+}

internal/handlers.go

@@ -8,6 +8,8 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/nxshock/signaller/internal/models/registeravailable"
+
 	"github.com/nxshock/signaller/internal/models/devices"
 
 	"github.com/gorilla/mux"
@@ -348,6 +350,26 @@ func DevicesHandler(w http.ResponseWriter, r *http.Request) {
 	sendJsonResponse(w, http.StatusOK, response)
 }
 
+// https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-register-available
+func registerAvailableHandler(w http.ResponseWriter, r *http.Request) {
+	var request registeravailable.Request
+
+	err := getRequest(r, &request)
+	if err != nil {
+		errorResponse(w, models.M_BAD_JSON, http.StatusBadRequest, err.Error())
+		return
+	}
+
+	user := currServer.Backend.GetUserByName(request.Username) // TODO: add validation of username
+	if user != nil {
+		errorResponse(w, models.M_USER_IN_USE, http.StatusBadRequest, "Desired user ID is already taken.")
+		return
+	}
+
+	response := registeravailable.Response{Available: false}
+	sendJsonResponse(w, http.StatusOK, response)
+}
+
 // https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-directory-list-room-roomid
 // https://matrix.org/docs/spec/client_server/latest#put-matrix-client-r0-directory-list-room-roomid
 func listRoomHandler(w http.ResponseWriter, r *http.Request) {

internal/models/registeravailable/registeravailable.go

@@ -0,0 +1,9 @@
+package registeravailable
+
+type Request struct {
+	Username string `json:"username"` // The username to check the availability of.
+}
+
+type Response struct {
+	Available bool `json:"available"` // A flag to indicate that the username is available. This should always be true when the server replies with 200 OK.
+}

internal/server.go

@@ -38,6 +38,7 @@ func NewServer(port int) (*Server, error) {
 	router.HandleFunc("/_matrix/client/r0/devices", DevicesHandler)
 	router.HandleFunc("/_matrix/client/r0/directory/list/room/{roomID}", listRoomHandler)
 	router.HandleFunc("/_matrix/client/r0/rooms/{roomId}/leave", leaveRoomHandler)
+	router.HandleFunc("/_matrix/client/r0/register/available", registerAvailableHandler)
 	router.HandleFunc("/", RootHandler)
 
 	if port <= 0 || port > 65535 {