streaming JSON encoding and decoding from HTTP client instead of allocating bytes

client.go

@@ -39,6 +39,7 @@ type Client struct {
 
 // HTTPError An HTTP Error response, which may wrap an underlying native Go Error.
 type HTTPError struct {
+	Contents     []byte
 	WrappedError error
 	Message      string
 	Code         int
@@ -49,7 +50,7 @@ func (e HTTPError) Error() string {
 	if e.WrappedError != nil {
 		wrappedErrMsg = e.WrappedError.Error()
 	}
-	return fmt.Sprintf("msg=%s code=%d wrapped=%s", e.Message, e.Code, wrappedErrMsg)
+	return fmt.Sprintf("contents=%v msg=%s code=%d wrapped=%s", e.Contents, e.Message, e.Code, wrappedErrMsg)
 }
 
 // BuildURL builds a URL with the Client's homserver/prefix/access_token set already.
@@ -183,27 +184,27 @@ func (cli *Client) StopSync() {
 }
 
 // MakeRequest makes a JSON HTTP request to the given URL.
-// If "resBody" is not nil, the response body will be json.Unmarshalled into it.
+// The response body will be stream decoded into an interface. This will automatically stop if the response
+// body is nil.
 //
-// Returns the HTTP body as bytes on 2xx with a nil error. Returns an error if the response is not 2xx along
+// Returns an error if the response is not 2xx along with the HTTP body bytes if it got that far. This error is
-// with the HTTP body bytes if it got that far. This error is an HTTPError which includes the returned
+// an HTTPError which includes the returned HTTP status code, byte contents of the response body and possibly a 
-// HTTP status code and possibly a RespError as the WrappedError, if the HTTP body could be decoded as a RespError.
+// RespError as the WrappedError, if the HTTP body could be decoded as a RespError.
-func (cli *Client) MakeRequest(method string, httpURL string, reqBody interface{}, resBody interface{}) ([]byte, error) {
+func (cli *Client) MakeRequest(method string, httpURL string, reqBody interface{}, resBody interface{}) error {
 	var req *http.Request
 	var err error
 	if reqBody != nil {
-		var jsonStr []byte
+		buf := new(bytes.Buffer)
-		jsonStr, err = json.Marshal(reqBody)
+		if err := json.NewEncoder(buf).Encode(reqBody); err != nil {
-		if err != nil {
+			return err
-			return nil, err
 		}
-		req, err = http.NewRequest(method, httpURL, bytes.NewBuffer(jsonStr))
+		req, err = http.NewRequest(method, httpURL, buf)
 	} else {
 		req, err = http.NewRequest(method, httpURL, nil)
 	}
 
 	if err != nil {
-		return nil, err
+		return err
 	}
 	req.Header.Set("Content-Type", "application/json")
 	res, err := cli.Client.Do(req)
@@ -211,10 +212,14 @@ func (cli *Client) MakeRequest(method string, httpURL string, reqBody interface{
 		defer res.Body.Close()
 	}
 	if err != nil {
-		return nil, err
+		return err
 	}
-	contents, err := ioutil.ReadAll(res.Body)
 	if res.StatusCode/100 != 2 { // not 2xx
+		contents, err := ioutil.ReadAll(res.Body)
+		if err != nil {
+			return err
+		}
+
 		var wrap error
 		var respErr RespError
 		if _ = json.Unmarshal(contents, &respErr); respErr.ErrCode != "" {
@@ -228,29 +233,25 @@ func (cli *Client) MakeRequest(method string, httpURL string, reqBody interface{
 			msg = msg + ": " + string(contents)
 		}
 
-		return contents, HTTPError{
+		return HTTPError{
+			Contents:     contents,
 			Code:         res.StatusCode,
 			Message:      msg,
 			WrappedError: wrap,
 		}
 	}
-	if err != nil {
+
-		return nil, err
+	if res.ContentLength > 0 {
+		return json.NewDecoder(res.Body).Decode(&resBody)
 	}
 
-	if resBody != nil {
+	return nil
-		if err = json.Unmarshal(contents, &resBody); err != nil {
-			return nil, err
-		}
-	}
-
-	return contents, nil
 }
 
 // CreateFilter makes an HTTP request according to http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-user-userid-filter
 func (cli *Client) CreateFilter(filter json.RawMessage) (resp *RespCreateFilter, err error) {
 	urlPath := cli.BuildURL("user", cli.UserID, "filter")
-	_, err = cli.MakeRequest("POST", urlPath, &filter, &resp)
+	err = cli.MakeRequest("POST", urlPath, &filter, &resp)
 	return
 }
 
@@ -272,13 +273,12 @@ func (cli *Client) SyncRequest(timeout int, since, filterID string, fullState bo
 		query["full_state"] = "true"
 	}
 	urlPath := cli.BuildURLWithQuery([]string{"sync"}, query)
-	_, err = cli.MakeRequest("GET", urlPath, nil, &resp)
+	err = cli.MakeRequest("GET", urlPath, nil, &resp)
 	return
 }
 
 func (cli *Client) register(u string, req *ReqRegister) (resp *RespRegister, uiaResp *RespUserInteractive, err error) {
-	var bodyBytes []byte
+	err = cli.MakeRequest("POST", u, req, &resp)
-	bodyBytes, err = cli.MakeRequest("POST", u, req, nil)
 	if err != nil {
 		httpErr, ok := err.(HTTPError)
 		if !ok { // network error
@@ -286,13 +286,10 @@ func (cli *Client) register(u string, req *ReqRegister) (resp *RespRegister, uia
 		}
 		if httpErr.Code == 401 {
 			// body should be RespUserInteractive, if it isn't, fail with the error
-			err = json.Unmarshal(bodyBytes, &uiaResp)
+			err = json.Unmarshal(httpErr.Contents, &uiaResp)
 			return
 		}
-		return
 	}
-	// body should be RespRegister
-	err = json.Unmarshal(bodyBytes, &resp)
 	return
 }
 
@@ -356,7 +353,7 @@ func (cli *Client) RegisterDummy(req *ReqRegister) (*RespRegister, error) {
 // This does not set credentials on this client instance. See SetCredentials() instead.
 func (cli *Client) Login(req *ReqLogin) (resp *RespLogin, err error) {
 	urlPath := cli.BuildURL("login")
-	_, err = cli.MakeRequest("POST", urlPath, req, &resp)
+	err = cli.MakeRequest("POST", urlPath, req, &resp)
 	return
 }
 
@@ -364,14 +361,14 @@ func (cli *Client) Login(req *ReqLogin) (resp *RespLogin, err error) {
 // This does not clear the credentials from the client instance. See ClearCredentials() instead.
 func (cli *Client) Logout() (resp *RespLogout, err error) {
 	urlPath := cli.BuildURL("logout")
-	_, err = cli.MakeRequest("POST", urlPath, nil, &resp)
+	err = cli.MakeRequest("POST", urlPath, nil, &resp)
 	return
 }
 
 // Versions returns the list of supported Matrix versions on this homeserver. See http://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-versions
 func (cli *Client) Versions() (resp *RespVersions, err error) {
 	urlPath := cli.BuildBaseURL("_matrix", "client", "versions")
-	_, err = cli.MakeRequest("GET", urlPath, nil, &resp)
+	err = cli.MakeRequest("GET", urlPath, nil, &resp)
 	return
 }
 
@@ -388,21 +385,21 @@ func (cli *Client) JoinRoom(roomIDorAlias, serverName string, content interface{
 	} else {
 		urlPath = cli.BuildURL("join", roomIDorAlias)
 	}
-	_, err = cli.MakeRequest("POST", urlPath, content, &resp)
+	err = cli.MakeRequest("POST", urlPath, content, &resp)
 	return
 }
 
 // GetDisplayName returns the display name of the user from the specified MXID. See https://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-r0-profile-userid-displayname
 func (cli *Client) GetDisplayName(mxid string) (resp *RespUserDisplayName, err error) {
 	urlPath := cli.BuildURL("profile", mxid, "displayname")
-	_, err = cli.MakeRequest("GET", urlPath, nil, &resp)
+	err = cli.MakeRequest("GET", urlPath, nil, &resp)
 	return
 }
 
 // GetOwnDisplayName returns the user's display name. See https://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-r0-profile-userid-displayname
 func (cli *Client) GetOwnDisplayName() (resp *RespUserDisplayName, err error) {
 	urlPath := cli.BuildURL("profile", cli.UserID, "displayname")
-	_, err = cli.MakeRequest("GET", urlPath, nil, &resp)
+	err = cli.MakeRequest("GET", urlPath, nil, &resp)
 	return
 }
 
@@ -412,18 +409,18 @@ func (cli *Client) SetDisplayName(displayName string) (err error) {
 	s := struct {
 		DisplayName string `json:"displayname"`
 	}{displayName}
-	_, err = cli.MakeRequest("PUT", urlPath, &s, nil)
+	err = cli.MakeRequest("PUT", urlPath, &s, nil)
 	return
 }
 
 // GetAvatarURL gets the user's avatar URL. See http://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-r0-profile-userid-avatar-url
-func (cli *Client) GetAvatarURL() (url string, err error) {
+func (cli *Client) GetAvatarURL() (string, error) {
 	urlPath := cli.BuildURL("profile", cli.UserID, "avatar_url")
 	s := struct {
 		AvatarURL string `json:"avatar_url"`
 	}{}
 
-	_, err = cli.MakeRequest("GET", urlPath, nil, &s)
+	err := cli.MakeRequest("GET", urlPath, nil, &s)
 	if err != nil {
 		return "", err
 	}
@@ -432,12 +429,12 @@ func (cli *Client) GetAvatarURL() (url string, err error) {
 }
 
 // SetAvatarURL sets the user's avatar URL. See http://matrix.org/docs/spec/client_server/r0.2.0.html#put-matrix-client-r0-profile-userid-avatar-url
-func (cli *Client) SetAvatarURL(url string) (err error) {
+func (cli *Client) SetAvatarURL(url string) error {
 	urlPath := cli.BuildURL("profile", cli.UserID, "avatar_url")
 	s := struct {
 		AvatarURL string `json:"avatar_url"`
 	}{url}
-	_, err = cli.MakeRequest("PUT", urlPath, &s, nil)
+	err := cli.MakeRequest("PUT", urlPath, &s, nil)
 	if err != nil {
 		return err
 	}
@@ -450,7 +447,7 @@ func (cli *Client) SetAvatarURL(url string) (err error) {
 func (cli *Client) SendMessageEvent(roomID string, eventType string, contentJSON interface{}) (resp *RespSendEvent, err error) {
 	txnID := txnID()
 	urlPath := cli.BuildURL("rooms", roomID, "send", eventType, txnID)
-	_, err = cli.MakeRequest("PUT", urlPath, contentJSON, &resp)
+	err = cli.MakeRequest("PUT", urlPath, contentJSON, &resp)
 	return
 }
 
@@ -458,7 +455,7 @@ func (cli *Client) SendMessageEvent(roomID string, eventType string, contentJSON
 // contentJSON should be a pointer to something that can be encoded as JSON using json.Marshal.
 func (cli *Client) SendStateEvent(roomID, eventType, stateKey string, contentJSON interface{}) (resp *RespSendEvent, err error) {
 	urlPath := cli.BuildURL("rooms", roomID, "state", eventType, stateKey)
-	_, err = cli.MakeRequest("PUT", urlPath, contentJSON, &resp)
+	err = cli.MakeRequest("PUT", urlPath, contentJSON, &resp)
 	return
 }
 
@@ -502,7 +499,7 @@ func (cli *Client) SendNotice(roomID, text string) (*RespSendEvent, error) {
 func (cli *Client) RedactEvent(roomID, eventID string, req *ReqRedact) (resp *RespSendEvent, err error) {
 	txnID := txnID()
 	urlPath := cli.BuildURL("rooms", roomID, "redact", eventID, txnID)
-	_, err = cli.MakeRequest("PUT", urlPath, req, &resp)
+	err = cli.MakeRequest("PUT", urlPath, req, &resp)
 	return
 }
 
@@ -513,56 +510,56 @@ func (cli *Client) RedactEvent(roomID, eventID string, req *ReqRedact) (resp *Re
 //  fmt.Println("Room:", resp.RoomID)
 func (cli *Client) CreateRoom(req *ReqCreateRoom) (resp *RespCreateRoom, err error) {
 	urlPath := cli.BuildURL("createRoom")
-	_, err = cli.MakeRequest("POST", urlPath, req, &resp)
+	err = cli.MakeRequest("POST", urlPath, req, &resp)
 	return
 }
 
 // LeaveRoom leaves the given room. See http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-rooms-roomid-leave
 func (cli *Client) LeaveRoom(roomID string) (resp *RespLeaveRoom, err error) {
 	u := cli.BuildURL("rooms", roomID, "leave")
-	_, err = cli.MakeRequest("POST", u, struct{}{}, &resp)
+	err = cli.MakeRequest("POST", u, struct{}{}, &resp)
 	return
 }
 
 // ForgetRoom forgets a room entirely. See http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-rooms-roomid-forget
 func (cli *Client) ForgetRoom(roomID string) (resp *RespForgetRoom, err error) {
 	u := cli.BuildURL("rooms", roomID, "forget")
-	_, err = cli.MakeRequest("POST", u, struct{}{}, &resp)
+	err = cli.MakeRequest("POST", u, struct{}{}, &resp)
 	return
 }
 
 // InviteUser invites a user to a room. See http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-rooms-roomid-invite
 func (cli *Client) InviteUser(roomID string, req *ReqInviteUser) (resp *RespInviteUser, err error) {
 	u := cli.BuildURL("rooms", roomID, "invite")
-	_, err = cli.MakeRequest("POST", u, req, &resp)
+	err = cli.MakeRequest("POST", u, req, &resp)
 	return
 }
 
 // InviteUserByThirdParty invites a third-party identifier to a room. See http://matrix.org/docs/spec/client_server/r0.2.0.html#invite-by-third-party-id-endpoint
 func (cli *Client) InviteUserByThirdParty(roomID string, req *ReqInvite3PID) (resp *RespInviteUser, err error) {
 	u := cli.BuildURL("rooms", roomID, "invite")
-	_, err = cli.MakeRequest("POST", u, req, &resp)
+	err = cli.MakeRequest("POST", u, req, &resp)
 	return
 }
 
 // KickUser kicks a user from a room. See http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-rooms-roomid-kick
 func (cli *Client) KickUser(roomID string, req *ReqKickUser) (resp *RespKickUser, err error) {
 	u := cli.BuildURL("rooms", roomID, "kick")
-	_, err = cli.MakeRequest("POST", u, req, &resp)
+	err = cli.MakeRequest("POST", u, req, &resp)
 	return
 }
 
 // BanUser bans a user from a room. See http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-rooms-roomid-ban
 func (cli *Client) BanUser(roomID string, req *ReqBanUser) (resp *RespBanUser, err error) {
 	u := cli.BuildURL("rooms", roomID, "ban")
-	_, err = cli.MakeRequest("POST", u, req, &resp)
+	err = cli.MakeRequest("POST", u, req, &resp)
 	return
 }
 
 // UnbanUser unbans a user from a room. See http://matrix.org/docs/spec/client_server/r0.2.0.html#post-matrix-client-r0-rooms-roomid-unban
 func (cli *Client) UnbanUser(roomID string, req *ReqUnbanUser) (resp *RespUnbanUser, err error) {
 	u := cli.BuildURL("rooms", roomID, "unban")
-	_, err = cli.MakeRequest("POST", u, req, &resp)
+	err = cli.MakeRequest("POST", u, req, &resp)
 	return
 }
 
@@ -570,7 +567,7 @@ func (cli *Client) UnbanUser(roomID string, req *ReqUnbanUser) (resp *RespUnbanU
 func (cli *Client) UserTyping(roomID string, typing bool, timeout int64) (resp *RespTyping, err error) {
 	req := ReqTyping{Typing: typing, Timeout: timeout}
 	u := cli.BuildURL("rooms", roomID, "typing", cli.UserID)
-	_, err = cli.MakeRequest("PUT", u, req, &resp)
+	err = cli.MakeRequest("PUT", u, req, &resp)
 	return
 }
 
@@ -579,7 +576,7 @@ func (cli *Client) UserTyping(roomID string, typing bool, timeout int64) (resp *
 // See http://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-r0-rooms-roomid-state-eventtype-statekey
 func (cli *Client) StateEvent(roomID, eventType, stateKey string, outContent interface{}) (err error) {
 	u := cli.BuildURL("rooms", roomID, "state", eventType, stateKey)
-	_, err = cli.MakeRequest("GET", u, nil, outContent)
+	err = cli.MakeRequest("GET", u, nil, outContent)
 	return
 }
 
@@ -620,6 +617,7 @@ func (cli *Client) UploadToContentRepo(content io.Reader, contentType string, co
 			}
 		}
 		return nil, HTTPError{
+			Contents: contents,
 			Message:  "Upload request failed: " + string(contents),
 			Code:     res.StatusCode,
 		}
@@ -637,7 +635,7 @@ func (cli *Client) UploadToContentRepo(content io.Reader, contentType string, co
 // This API is primarily designed for application services which may want to efficiently look up joined members in a room.
 func (cli *Client) JoinedMembers(roomID string) (resp *RespJoinedMembers, err error) {
 	u := cli.BuildURL("rooms", roomID, "joined_members")
-	_, err = cli.MakeRequest("GET", u, nil, &resp)
+	err = cli.MakeRequest("GET", u, nil, &resp)
 	return
 }
 
@@ -647,7 +645,7 @@ func (cli *Client) JoinedMembers(roomID string) (resp *RespJoinedMembers, err er
 // This API is primarily designed for application services which may want to efficiently look up joined rooms.
 func (cli *Client) JoinedRooms() (resp *RespJoinedRooms, err error) {
 	u := cli.BuildURL("joined_rooms")
-	_, err = cli.MakeRequest("GET", u, nil, &resp)
+	err = cli.MakeRequest("GET", u, nil, &resp)
 	return
 }
 
@@ -667,7 +665,7 @@ func (cli *Client) Messages(roomID, from, to string, dir rune, limit int) (resp
 	}
 
 	urlPath := cli.BuildURLWithQuery([]string{"rooms", roomID, "messages"}, query)
-	_, err = cli.MakeRequest("GET", urlPath, nil, &resp)
+	err = cli.MakeRequest("GET", urlPath, nil, &resp)
 	return
 }
 
@@ -675,7 +673,7 @@ func (cli *Client) Messages(roomID, from, to string, dir rune, limit int) (resp
 // See http://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-r0-voip-turnserver
 func (cli *Client) TurnServer() (resp *RespTurnServer, err error) {
 	urlPath := cli.BuildURL("voip", "turnServer")
-	_, err = cli.MakeRequest("GET", urlPath, nil, &resp)
+	err = cli.MakeRequest("GET", urlPath, nil, &resp)
 	return
 }