instagram: adds support for share urls

ext/instagram/main.go

@@ -29,6 +29,23 @@ const (
 	// to get the API key and timestamp
 )
 
+var igHeaders = map[string]string{
+	"Accept":                    "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7",
+	"Accept-Language":           "en-GB,en;q=0.9",
+	"Cache-Control":             "max-age=0",
+	"Dnt":                       "1",
+	"Priority":                  "u=0, i",
+	"Sec-Ch-Ua":                 `Chromium";v="124", "Google Chrome";v="124", "Not-A.Brand";v="99`,
+	"Sec-Ch-Ua-Mobile":          "?0",
+	"Sec-Ch-Ua-Platform":        "macOS",
+	"Sec-Fetch-Dest":            "document",
+	"Sec-Fetch-Mode":            "navigate",
+	"Sec-Fetch-Site":            "none",
+	"Sec-Fetch-User":            "?1",
+	"Upgrade-Insecure-Requests": "1",
+	"User-Agent":                util.ChromeUA,
+}
+
 var HTTPClient = &http.Client{
 	Transport: &http3.Transport{
 		TLSClientConfig: &tls.Config{
@@ -73,6 +90,37 @@ var StoriesExtractor = &models.Extractor{
 	},
 }
 
+var ShareURLExtractor = &models.Extractor{
+	Name:       "Instagram Share URL",
+	CodeName:   "instagram:share",
+	Type:       enums.ExtractorTypeSingle,
+	Category:   enums.ExtractorCategorySocial,
+	URLPattern: regexp.MustCompile(`https?:\/\/(www\.)?instagram\.com\/share\/((reels?|video|s|p)\/)?(?P<id>[^\/\?]+)`),
+	IsRedirect: true,
+
+	Run: func(ctx *models.DownloadContext) (*models.ExtractorResponse, error) {
+		req, err := http.NewRequest(
+			http.MethodGet,
+			ctx.MatchedContentURL,
+			nil,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("failed to create request: %w", err)
+		}
+		for k, v := range igHeaders {
+			req.Header.Set(k, v)
+		}
+		resp, err := HTTPClient.Do(req)
+		if err != nil {
+			return nil, fmt.Errorf("failed to send request: %w", err)
+		}
+		defer resp.Body.Close()
+		return &models.ExtractorResponse{
+			URL: resp.Request.URL.String(),
+		}, nil
+	},
+}
+
 func MediaListFromAPI(
 	ctx *models.DownloadContext,
 	stories bool,