Date: 2026-04-04
MOV video support for iOS
iOS records video as QuickTime MOV files. The backend extension allowlist only had .mp4 for video — .mov wasn't accepted at all. Adding it was more involved than just appending to the list.
Go's http.DetectContentType uses the MIME sniffing spec, which doesn't recognize the QuickTime ftyp brand. It returns application/octet-stream for valid MOV files. The solution is a secondary validation step: if the detected MIME is application/octet-stream and the extension is .mov, read bytes 4–8 of the file and check the 4CC box type. Valid QuickTime/MP4 containers start with ftyp, moov, free, wide, or mdat. This is a tight enough check to accept real MOV files while rejecting arbitrary binary blobs masquerading as video.
Video thumbnail generation
After upload, the server generates a JPEG thumbnail from the first frame using ffmpeg via exec.Command. The thumbnail is served as a static file alongside the video and included in the post response so the feed can show a preview image without loading the full video. The generation happens in a goroutine so it doesn't block the upload response.
Audio file uploads
image_picker only handles images and video. For audio, switched to the file_picker package which opens the system file picker with FileType.audio. On iOS Safari this surfaces the Files app (and iCloud Drive) where downloaded or saved audio lives.
The backend accepts .mp3, .wav, and .flac with proper MIME validation.
Audio player widget
Built a custom audio player using the audioplayers package: gradient play/pause button, scrubber slider with mm:ss timestamps for current position and duration. Styled to match the app theme with violet/pink gradients and a subtle glassmorphism container. The player listens to onPlayerStateChanged, onPositionChanged, and onDurationChanged streams from AudioPlayer and rebuilds only the relevant parts of the widget tree on each tick.