burgerbackup/lib/client/main.go

package client

import (
	"bytes"
	"concord.hectabit.org/Hectabit/burgerbackup/lib/common"
	"encoding/base64"
	"encoding/json"
	"errors"
	"golang.org/x/crypto/argon2"
	"io"
	"log"
	"mime/multipart"
	"net/http"
	"os"
	"strconv"
)

func PerformBackup(fileLocation string, backupKey string, cryptoKey string, remoteURL string) (error, int) {
	fileContent, err := os.ReadFile(fileLocation)
	if err != nil {
		log.Println("[CRITICAL] Unknown in PerformBackup() file read:", err)
		return err, 0
	}

	fileInfo, err := os.Stat(fileLocation)
	if err != nil {
		log.Println("[CRITICAL] Unknown in PerformBackup() file stat:", err)
		return err, 1
	}
	filename := fileInfo.Name()

	content := map[string]interface{}{
		"filename": filename,
		"content":  base64.StdEncoding.EncodeToString(fileContent),
	}

	marshaledContent, err := json.Marshal(content)
	if err != nil {
		log.Println("[CRITICAL] Unknown in PerformBackup() content marshal:", err)
		return err, 2
	}

	cryptoKeyHashed := argon2.IDKey([]byte(cryptoKey), []byte("burgerbackup"), 1, 64*1024, 4, 32)
	encryptedContent, err := common.EncryptAES(cryptoKeyHashed, marshaledContent)
	if err != nil {
		log.Println("[CRITICAL] Unknown in PerformBackup() content encryption", err)
		return err, 3
	}

	encryptedFile := io.NopCloser(bytes.NewReader(encryptedContent))
	err, errCode := SendFileToServer(encryptedFile, backupKey, remoteURL, filename)
	if err != nil {
		return err, errCode + 4
	}

	log.Println("[INFO] Backup completed at:")
	return nil, -1
}

func SendFileToServer(file io.Reader, backupKey string, remoteURL string, filename string) (error, int) {
	sendBody := &bytes.Buffer{}
	writer := multipart.NewWriter(sendBody)
	part, err := writer.CreateFormFile("file", filename)
	if err != nil {
		return err, 0
	}

	_, err = io.Copy(part, file)
	if err != nil {
		return err, 1
	}

	err = writer.Close()
	if err != nil {
		return err, 3
	}

	req, err := http.NewRequest("POST", remoteURL, sendBody)
	if err != nil {
		return err, 4
	}

	salt, err := common.GenSalt(16)
	hashedBackupKey, err := common.Hash(backupKey, salt)
	if err != nil {
		return err, 5
	}
	req.Header.Set("Authorization", hashedBackupKey)
	req.Header.Set("Content-Type", writer.FormDataContentType())
	req.Header.Set("Content-Length", strconv.Itoa(sendBody.Len()))

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return err, 6
	}
	defer func(Body io.ReadCloser) {
		err := Body.Close()
		if err != nil {
			log.Println("[ERROR] Error in sendFileToServer() response defer:", err)
		}
	}(resp.Body)

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return err, 7
	}

	var response map[string]interface{}
	err = json.Unmarshal(body, &response)
	if err != nil {
		return err, 8
	}

	if resp.StatusCode != 200 {
		err, ok := response["goErr"].(string)
		if !ok {
			err = "error not sent by server"
		}
		return errors.New(err), 9
	}

	return nil, -1
}