Download files generated in a WebView

nuthinking

I'm still trying to figure out how to download files (video, gif) generated in a WebView. Tried many options. Ultimately, the WebView seems to prevent downloads and also to send complex data back to the plugin. Ideas? 🙏

kevgski

Spent a little time trying to figure this one out but since I can’t seem to get the web inspector working to debug the webview context making it pretty hard to help you...

Personally, I wouldn’t use a webview. Seems like there are some changes Sketch has made to the app runtime that make downloading things via a webview much harder. While there is a steeper learning curve, the cocoa apis offer quite a bit of flexibility and make this quite a bit simpler.

That being said I think you are on the right track.

You can use the FileReader api to create a base64 representation.
Send that over to the plugin js context via window.postMessage
Convert that bas64 string to a NSData object NSData.dataFromBase64String(string)
Then write the data file to disc using data.writeToFile_ atomically(‘\path_to_where_video_will_be.mp4’,false)

nuthinking

Is there any size limit for the base64 representation or it's simply the RAM? If so, I guess dozens of MBs will be ok, hundreds probably not. Thanks!

nuthinking

Looks like I can pass the base64 string to the plugin, but then can't save it neither use NSData or convert it to Array buffer and using Node. Unfortunately debugging is impossible, also because of: The extension “sketch-dev-tools” is not compatible with your computer’s CPU architecture. Please contact this extension’s developer directly for assistance.

nuthinking

Had to strip out the initial bit from the base64 string(data:application/octet-stream;base64,) and use NSData.alloc().initWithBase64Encoding. It also throws a weird exception, still not sure what it is, but I think I can say that overall it works. Thanks a lot! 🙏