1package invidious
  2
  3import (
  4	"bytes"
  5	"encoding/json"
  6	"fmt"
  7	"io"
  8	"net/http"
  9	"net/url"
 10	"regexp"
 11	"strconv"
 12	"time"
 13
 14	"github.com/sirupsen/logrus"
 15)
 16
 17const timeoutDuration = 10 * time.Minute
 18const maxSizeMB = 50
 19const instancesEndpoint = "https://api.invidious.io/instances.json?sort_by=api,type"
 20const videosEndpoint = "https://%s/api/v1/videos/%s?fields=videoId,title,description,author,lengthSeconds,size,formatStreams"
 21
 22var expireRegex = regexp.MustCompile(`(?i)expire=(\d+)`)
 23var logger = logrus.New()
 24
 25type Timeout struct {
 26	Instance  string
 27	Timestamp time.Time
 28}
 29
 30type Client struct {
 31	http     *http.Client
 32	timeouts []Timeout
 33	Instance string
 34}
 35
 36type Format struct {
 37	VideoId   string
 38	Name      string `json:"qualityLabel"`
 39	Height    int
 40	Width     int
 41	Url       string `json:"url"`
 42	Container string `json:"container"`
 43	Size      string `json:"size"`
 44}
 45
 46type Video struct {
 47	VideoId     string   `json:"videoId"`
 48	Title       string   `json:"title"`
 49	Description string   `json:"description"`
 50	Uploader    string   `json:"author"`
 51	Duration    int      `json:"lengthSeconds"`
 52	Formats     []Format `json:"formatStreams"`
 53	Timestamp   time.Time
 54	Expire      time.Time
 55	FormatIndex int
 56}
 57
 58func filter[T any](ss []T, test func(T) bool) (ret []T) {
 59	for _, s := range ss {
 60		if test(s) {
 61			ret = append(ret, s)
 62		}
 63	}
 64	return
 65}
 66
 67func parseOrZero(number string) int {
 68	res, err := strconv.Atoi(number)
 69	if err != nil {
 70		return 0
 71	}
 72	return res
 73}
 74
 75type HTTPError struct {
 76	StatusCode int
 77}
 78
 79func (e HTTPError) Error() string {
 80	return fmt.Sprintf("HTTP error: %d", e.StatusCode)
 81}
 82
 83func (c *Client) fetchVideo(videoId string) (*Video, error) {
 84	if c.Instance == "" {
 85		err := c.NewInstance()
 86		if err != nil {
 87			logger.Fatal(err, "Could not get a new instance.")
 88		}
 89	}
 90	endpoint := fmt.Sprintf(videosEndpoint, c.Instance, url.QueryEscape(videoId))
 91	resp, err := c.http.Get(endpoint)
 92	if err != nil {
 93		return nil, err
 94	}
 95	defer resp.Body.Close()
 96
 97	body, err := io.ReadAll(resp.Body)
 98	if err != nil {
 99		return nil, err
100	}
101
102	if resp.StatusCode != http.StatusOK {
103		return nil, HTTPError{resp.StatusCode}
104	}
105
106	res := &Video{}
107	err = json.Unmarshal(body, res)
108	if err != nil {
109		return nil, err
110	}
111
112	mp4Test := func(f Format) bool { return f.Container == "mp4" }
113	res.Formats = filter(res.Formats, mp4Test)
114
115	expireString := expireRegex.FindStringSubmatch(res.Formats[0].Url)
116	expireTimestamp, err := strconv.ParseInt(expireString[1], 10, 64)
117	if err != nil {
118		fmt.Println("Error:", err)
119		return nil, err
120	}
121	res.Expire = time.Unix(expireTimestamp, 0)
122
123	return res, err
124}
125
126func (c *Client) GetVideo(videoId string) (*Video, error) {
127	logger.Info("Video https://youtu.be/", videoId, " was requested.")
128
129	video, err := GetVideoDB(videoId)
130	if err == nil {
131		logger.Info("Found a valid cache entry.")
132		return video, nil
133	}
134
135	video, err = c.fetchVideo(videoId)
136
137	if err != nil {
138		if httpErr, ok := err.(HTTPError); ok {
139			// handle HTTPError
140			if httpErr.StatusCode == http.StatusNotFound {
141				logger.Debug("Video does not exist.")
142				return nil, err
143			}
144			logger.Debug("Invidious HTTP error: ", httpErr.StatusCode)
145		}
146		// handle generic error
147		logger.Error(err)
148		err = c.NewInstance()
149		if err != nil {
150			logger.Error("Could not get a new instance: ", err)
151			time.Sleep(10 * time.Second)
152		}
153		return c.GetVideo(videoId)
154	}
155	logger.Info("Retrieved by API.")
156
157	CacheVideoDB(*video)
158	return video, nil
159}
160
161func (c *Client) isNotTimedOut(instance string) bool {
162	for i := range c.timeouts {
163		cur := c.timeouts[i]
164		if instance == cur.Instance {
165			return false
166		}
167	}
168	return true
169}
170
171func (c *Client) NewInstance() error {
172	now := time.Now()
173
174	timeoutsTest := func(t Timeout) bool { return now.Sub(t.Timestamp) < timeoutDuration }
175	c.timeouts = filter(c.timeouts, timeoutsTest)
176
177	timeout := Timeout{c.Instance, now}
178	c.timeouts = append(c.timeouts, timeout)
179
180	resp, err := c.http.Get(instancesEndpoint)
181	if err != nil {
182		return err
183	}
184	defer resp.Body.Close()
185
186	body, err := io.ReadAll(resp.Body)
187	if err != nil {
188		return err
189	}
190
191	if resp.StatusCode != http.StatusOK {
192		return fmt.Errorf(string(body))
193	}
194
195	var jsonArray [][]interface{}
196	err = json.Unmarshal(body, &jsonArray)
197	if err != nil {
198		return err
199	}
200
201	for i := range jsonArray {
202		instance := jsonArray[i][0].(string)
203		instanceTest := func(t Timeout) bool { return t.Instance == instance }
204		result := filter(c.timeouts, instanceTest)
205		if len(result) == 0 {
206			c.Instance = instance
207			logger.Info("Using new instance: ", c.Instance)
208			return nil
209		}
210	}
211	logger.Error("Cannot find a valid instance.")
212	return err
213}
214
215func (c *Client) ProxyVideo(w http.ResponseWriter, videoId string, formatIndex int) error {
216	video, err := GetVideoDB(videoId)
217	if err != nil {
218		logger.Debug("Cannot proxy a video that is not cached: https://youtu.be/", videoId)
219		http.Error(w, "Bad Request", http.StatusBadRequest)
220		return err
221	}
222
223	fmtAmount := len(video.Formats)
224	idx := formatIndex % fmtAmount
225	url := video.Formats[fmtAmount-1-idx].Url
226	req, err := http.NewRequest(http.MethodGet, url, nil)
227	if err != nil {
228		logger.Error(err)
229		new_video, err := c.fetchVideo(videoId)
230		if err != nil {
231			logger.Error("Url for", videoId, "expired:", err)
232			return err
233		}
234		return c.ProxyVideo(w, new_video.VideoId, formatIndex)
235	}
236
237	req.Header.Add("Range", fmt.Sprintf("bytes=0-%d000000", maxSizeMB))
238	resp, err := c.http.Do(req)
239	if err != nil {
240		logger.Error(err)
241		http.Error(w, err.Error(), http.StatusInternalServerError)
242		return err
243	}
244	defer resp.Body.Close()
245
246	w.Header().Set("content-type", "video/mp4")
247	w.Header().Set("Status", "200")
248
249	temp := bytes.NewBuffer(nil)
250	_, err = io.Copy(temp, resp.Body)
251	if err == nil { // done
252		_, err = io.Copy(w, temp)
253		return err
254	}
255
256	newIndex := formatIndex + 1
257	if newIndex < fmtAmount {
258		return c.ProxyVideo(w, videoId, newIndex)
259	}
260	_, err = io.Copy(w, temp)
261	return err
262}
263
264func NewClient(httpClient *http.Client) *Client {
265	InitDB()
266	return &Client{
267		http:     httpClient,
268		timeouts: []Timeout{},
269		Instance: "",
270	}
271}