feat: add `file-transfer` plugin

[robingenz]

Is your feature request related to a problem? Please describe:

Currently there is no Capacitor 4 compatible plugin that can be used to upload and download files.

Describe the solution you'd like:

Create a plugin that allows you to upload and download files.

Describe alternatives you've considered:

Additional context:

Related to https://github.com/ionic-team/capacitor/issues/5964

[Tragio]

@robingenz there is this plugin https://github.com/AlwaysLoveme/capacitor-plugin-filedownload not sure if can help or contribute to it.

[muuvmuuv]

Capacitor Filesystem will soon be able to download files and Http has been updated to handle FormData and files in FormData.

[robingenz]

This plugin will offer advanced features. That is why it is still on the roadmap, at least for now.

[muuvmuuv]

Cool! Then I will add my "request" for an advanced-feature: progress event callback for each download instead/(additionally) of a listener on all request (like it is with the current implementation by Ionic-Team).

Our use-case is a download-widget which downloads >1800 files in parallel in batches and I would like to have a proper kb/s and estimated time progress in it. Our current implementation works but it requires to cache the url and loaded bytes in a Set and other hacky stuff to make it work.

[robingenz]

My current implementation (Android is done, iOS & Web is pending) also uses a listener for all uploads/downloads, but instead of using url to identify a request, I currently use a unique requestId. I may change this. There are of course more features to come. Be prepared and subscribe to the issue! Feel free to let me know if you have more ideas.

[muuvmuuv]

Ah, great, that would work a little better if it is returned with each event.

Just sharing my listener here for anyone looking for that:

Http download listener

private createHttpListener() {
  return Filesystem.addListener("progress", ({ url, bytes, contentLength }) => {
    const progress = new DownloadProgress(
      this.remaining,
      this.bytesTotal,
      this.bytesLoaded,
      contentLength,
    )

    if (!url.includes("your-domain.")) {
      // Files coming from other servers have no file size so we need to get that
      // value during file download.
      if (contentLength === 0) {
        // Some servers do not respond with a content length.
        this.event.downloadProgressChange.next(progress)
        return
      }
      if (!this.previousBytes.has(url)) {
        this.bytesTotal += contentLength
        this.previousBytes.set(url, 0)
      }
    }

    this.bytesLoaded += bytes - (this.previousBytes.get(url) || 0)
    this.previousBytes.set(url, bytes)

    this.event.downloadProgressChange.next(progress)
  })
}

[SchneMa]

Are there any infos when or in which version Upload/Download will be available?

[robingenz]

@SchneMa ETA is next month.

[coderpradp]

Any news on this?

[robingenz]

Any news on this?

I prioritized the development of another plugin for a sponsor (see https://github.com/capawesome-team/capacitor-firebase/pull/434). Therefore, the development of this plugin has been postponed.

[lsolano2707]

Any news?, I want to upload large files (videos) with capacitor without Ionic and I read "The File Handling Guide for Capacitor" and here mentions that there are plugins to upload files directly to server but I have no idea what they are

[robingenz]

@lsolano2707 A few plugins are:

• Firebase Cloud Storage
• Cloudinary

But this plugin is not yet available.