Add Go command implementations

internal/matrix/constants.go

@@ -0,0 +1,21 @@
+// Copyright Jan Dittberner
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+package matrix
+
+const (
+	TextMessage = "m.text"
+	HTMLFormat  = "org.matrix.custom.html"
+)

internal/matrix/message.go

@@ -0,0 +1,95 @@
+// Copyright Jan Dittberner
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+package matrix
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+)
+
+const transactionIDLength = 16
+
+type Message struct {
+	Type          string `json:"msgtype"`
+	Body          string `json:"body"`
+	FormattedBody string `json:"formatted_body"`
+	Format        string `json:"format"`
+}
+
+func SendMessage(server *url.URL, room string, token string, message string) error {
+	messageBytes, err := json.Marshal(Message{
+		Type:          TextMessage,
+		Body:          message,
+		FormattedBody: message,
+		Format:        HTMLFormat,
+	})
+	if err != nil {
+		return fmt.Errorf("could not build JSON message: %w", err)
+	}
+
+	transaction, err := generateTransactionID()
+	if err != nil {
+		return err
+	}
+
+	postURL := server.JoinPath("/_matrix/client/r0/rooms/", room, "/send/m.room.message/", transaction)
+
+	request, err := http.NewRequest(http.MethodPut, postURL.String(), bytes.NewBuffer(messageBytes))
+	if err != nil {
+		return fmt.Errorf("could not build request: %w", err)
+	}
+
+	request.Header.Set("Accept", "application/json")
+	request.Header.Set("Content-Type", "application/json")
+	request.Header.Set("Authorization", "Bearer "+token)
+
+	response, err := http.DefaultClient.Do(request)
+	if err != nil {
+		return fmt.Errorf("could not send request: %w", err)
+	}
+
+	defer func() {
+		_ = response.Body.Close()
+	}()
+
+	if response.StatusCode > http.StatusBadRequest {
+		responseBody, err := io.ReadAll(response.Body)
+		if err != nil {
+			return fmt.Errorf("received an error: %s, could not read response body: %w", response.Status, err)
+		}
+
+		return fmt.Errorf("received an error: %s %s", response.Status, string(responseBody))
+	}
+
+	return nil
+}
+
+func generateTransactionID() (string, error) {
+	IDBytes := make([]byte, transactionIDLength)
+
+	_, err := rand.Read(IDBytes)
+	if err != nil {
+		return "", fmt.Errorf("could not generate transaction id: %w", err)
+	}
+
+	return base64.RawURLEncoding.EncodeToString(IDBytes), nil
+}