gluetun-qbitt-sidecar/pkg/qbitt/client.go

package qbitt

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/http/cookiejar"
	"net/url"
	"strconv"
	"strings"
)

/*
Need to make a request to the qbittorrent API
	POST /api/v2/app/setPreferences
with structure:

	{
		"listen_port": 58925
	}

*/

const (
	LOGIN_PATH       = "/api/v2/auth/login"
	LOGOUT_PATH      = "/api/v2/auth/logout"
	PREFERENCES_PATH = "/api/v2/app/setPreferences"
	CONFIG_PATH      = "/api/v2/app/preferences"
)

type ListenPortRequest struct {
	ListenPort int `json:"listen_port"`
}

type Configuration struct {
	ListenPort int  `json:"listen_port"`
	RandomPort bool `json:"random_port"`
	Upnp       bool `json:"upnp"`
	Pex        bool `json:"pex"`
	Dht        bool `json:"dht"`
}

func makeListenPortRequest(port int) (string, error) {
	b, err := json.Marshal(ListenPortRequest{ListenPort: port})
	if err != nil {
		return "", err
	}
	return string(b), nil

}

type server struct {
	proto string // http or https
	host  string // just the domain name, like 'qbit.local.lan' or whatever
	port  int    // port that the web ui listens on
}

func (s server) format() string {
	return fmt.Sprintf("%s://%s:%v", s.proto, s.host, s.port)
}

func (s server) formatWith(path string) string {
	return fmt.Sprintf("%s%s", s.format(), path)
}

type QbittorrentClient struct {
	server server
	client *http.Client // plumbing
}

// takes string s and returns the host and port
func splitServerPort(s string) (string, int) {
	splitPort := strings.Split(s, ":")
	if len(splitPort) < 1 {
		// add log here
		log.Fatal("unhandled for now")
	}
	host := splitPort[0]
	port, err := strconv.Atoi(splitPort[1])
	if err != nil {
		log.Fatal("couldnt parse port. unhandled for now.")
	}
	return host, port

}

// strips everything but the port number and hostname from a string
func parseServer(s string) (server, error) {
	var proto, host string
	var port int
	if strings.Contains(s, "https") {
		proto = "https"
	} else {
		proto = "http"
	}
	protoStripped := strings.ReplaceAll(
		strings.ReplaceAll(
			strings.ReplaceAll(
				s, "https", "",
			), "http", "",
		), "://", "",
	)
	splitHost := strings.Split(protoStripped, "/")
	host, port = splitServerPort(splitHost[0])
	return server{proto: proto, host: host, port: port}, nil

}

/*
	 create a new qbit client
		:param username: username for your qbittorrent Web UI
		:param password: password for your qbittorrent Web UI
		:param host: the host/url of the server. should be in format: <protocol>://<host>:<port>
*/
func NewQbittorrentClient(username, password, host string) (QbittorrentClient, error) {
	ckJar, err := cookiejar.New(nil)
	client := http.Client{Jar: ckJar}
	srv, err := parseServer(host)
	if err != nil {
		return QbittorrentClient{}, err
	}
	formattedUrl := srv.formatWith(LOGIN_PATH)
	data := url.Values{}
	data.Set("username", username)
	data.Set("password", password)
	body := strings.NewReader(data.Encode())
	req, err := http.NewRequest(http.MethodPost, formattedUrl, body)
	if err != nil {
		return QbittorrentClient{}, err
	}
	req.Header.Add("Referer", srv.format())
	req.Header.Add("Origin", srv.format())
	req.Header.Add("Host", srv.host)
	// req.Header.Add("Content-Type", "text/plain")
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
	resp, err := client.Do(req)
	if err != nil {
		return QbittorrentClient{}, err
	}
	if resp.StatusCode != 200 {
		return QbittorrentClient{}, errors.New(fmt.Sprintf("Authentication failed.\n  Host: %s\n  Status Code: %s\n", srv.format(), resp.Status))
	}

	client.Jar.SetCookies(resp.Request.URL, resp.Cookies())
	return QbittorrentClient{server: srv, client: &client}, nil

}

// updates the listening port for incoming bittorrent requests to 'port' on your server
// :param port: the port to update for incoming connections
func (q QbittorrentClient) UpdateIncomingPort(port int) error {
	body, err := makeListenPortRequest(port)
	if err != nil {
		return err
	}
	data := url.Values{}
	data.Set("json", body)
	req, err := http.NewRequest(http.MethodPost, q.server.formatWith(PREFERENCES_PATH), strings.NewReader(data.Encode()))
	req.Header.Add("Origin", q.server.format())
	req.Header.Add("Referer", q.server.format())
	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
	resp, err := q.client.Do(req)
	if err != nil {
		return err
	}
	if resp.StatusCode != 200 {
		return errors.New(fmt.Sprintf("Update request failed.\n  Host: %s\n  Status Code: %s\n", q.server.format(), resp.Status))
	}
	return nil
}

// gets the running configuration
func (q QbittorrentClient) GetRunningConfiguration() (Configuration, error) {
	var cfg Configuration
	req, err := http.NewRequest(http.MethodGet, q.server.formatWith(CONFIG_PATH), nil)
	if err != nil {
		return cfg, err
	}
	req.Header.Add("Origin", q.server.format())
	req.Header.Add("Referer", q.server.format())
	resp, err := q.client.Do(req)
	if err != nil {
		return cfg, err
	}
	defer resp.Body.Close()
	b, err := io.ReadAll(resp.Body)
	if err != nil {
		return cfg, err
	}
	err = json.Unmarshal(b, &cfg)
	if err != nil {
		return cfg, err
	}
	return cfg, nil
}

// verify that the listening port was modified
func (q QbittorrentClient) VerifyPortChange(port int) (bool, error) {
	cfg, err := q.GetRunningConfiguration()
	if err != nil {
		return false, err
	}
	if cfg.ListenPort != port {
		return false, errors.New(fmt.Sprintf("Listening port on server: '%v' did not match what was supplied: '%v'\n", cfg.ListenPort, port))
	}
	return true, nil

}