Parse GIFs for in the GetTweet API

I am writing an app that needs to get info about all media in a tweet and forward it to a Telegram chat.

Today animated GIFs are ignored in the response of TweetDetail, although the are there (exept for the caveat mentioned below). So without this change the GIFs are not present in the twitterscraper.Tweet struct.

Following the analogy with the split between Photos and Videos I added GIFs to the Tweet type.

There is one caveat that I found during testing that I can't really explain. But GIFs don't occur in the response unless the bearerToken2 is set. I don't know what this token means, maybe it somehow identifies a destop-browser variant of twitter frontend, but with this token the GIFs are present in the response.

Please note that I never wrote Go code before in my life. I am using this library via the FFI to link it to my Rust codebase.

timeline_v2.go

@@ -261,6 +261,26 @@ func parseLegacyTweet(user *legacyUser, tweet *legacyTweet) *Tweet {
 			}
 
 			tw.Videos = append(tw.Videos, video)
+		} else if media.Type == "animated_gif" {
+			gif := GIF{
+				ID:      media.IDStr,
+				Preview: media.MediaURLHttps,
+			}
+
+			// Twitter's API doesn't provide bitrate for GIFs, (it's always set to zero).
+			// Therefore we check for `>=` instead of `>` in the loop below.
+			// Also, GIFs have just a single variant today. Just in case that changes in the future,
+			// and there will be multiple variants, we'll pick the one with the highest bitrate,
+			// if other one will have a non-zero bitrate.
+			maxBitrate := 0
+			for _, variant := range media.VideoInfo.Variants {
+				if variant.Bitrate >= maxBitrate {
+					gif.URL = variant.URL
+					maxBitrate = variant.Bitrate
+				}
+			}
+
+			tw.GIFs = append(tw.GIFs, gif)
 		}
 
 		if !tw.SensitiveContent {
@@ -315,6 +335,13 @@ func parseLegacyTweet(user *legacyUser, tweet *legacyTweet) *Tweet {
 		}
 		tw.HTML += fmt.Sprintf(`<br><img src="%s"/>`, url)
 	}
+	for _, gif := range tw.GIFs {
+		url := gif.Preview
+		if stringInSlice(url, foundedMedia) {
+			continue
+		}
+		tw.HTML += fmt.Sprintf(`<br><img src="%s"/>`, url)
+	}
 	tw.HTML = strings.Replace(tw.HTML, "\n", "<br>", -1)
 	return tw
 }