Storing a file in Companion

[Sanghuuuun]

I am trying to send a text file to a companion(simulator) from device(simulator). 

With the sample code in "https://dev.fitbit.com/build/guides/communications/file-transfer/", the companion only reads the contents of file via console.log. 

When I try to import "fs" in compaion, I got error that "cannot resolve fs". 

Is there an example code to save the file in folder related to the companion?

[Gondwana · Accepted solution]

fs is device-only.

The companion uses file-transfer.

This isn't sufficient to save the file into an accessible folder. For that, you'll need to use fetch() with a web server.

[JasonWoha]

Does the companion store the files received from the devices locally? Or it uploads it to the cloud automatically. And the developer needs to query them using the Web API?

[Gondwana]

@JasonWohaWhat files are you referring to?

[JasonWoha]

Files received from the device through file transfer.

[Gondwana]

In the companion, 'files' are actually received as a variable in memory.

[JasonWoha]

What are the ways to access those files from an external source?

[Gondwana]

Send it to a server using fetch().

[ac_devel]

Related to this topic .. I have a file that I get using fetch from aws. I am trying to send that data to my device but I get 

[4:31:12 PM] Companion: Failed to queue session_config.json: TypeError: Failed to execute 'enqueue' on 'FileTransferOutbox': The value provided as parameter 2 is not a valid buffer source                                                                                                                                                          (companion/index.js:82,7)

my code is this: 

 console.log('Enqueue file to device');
  outbox.enqueue(config_fname, config_data)
    .then((ft) => {
      console.log(`Transfer of ${ft.name} successfully queued.`);
    })
    .catch((error) => {
      console.log(`Failed to queue ${config_fname}: ${error}`);
    })

 where config_data is what I get from my fetch. What am I missing?  

[Gondwana]

Did you convert config_data into an ArrayBuffer or ArrayBufferView? See this.

[ac_devel]

@Gondwana ah! I missed that part. I was trying JSON.stringify thinking it was enough. I'll check it out. 
Would it it be possible to run fetch directly? 

[Gondwana]

---

@ac_devel wrote:

...Would it it be possible to run fetch directly? 

---

Not sure what you mean.

[ac_devel]

so I ran fetch on companion app and I was wondering if I can run the same thing on the watch directy. 

going back to the transfer, I was able to transfer the file but when I try to read it using

fs.readFileSync(configFilename)

I get 

 App: Unhandled exception: Error: Couldn't find file: undefined

[Gondwana]

No, the fetch API only exists in the companion. The watch doesn't have direct access to networking.

Where did you get configFilename from? When are you trying to read the file?

[ac_devel]

So the filename is hardcoded since it is one known file.
The processing of the queue is done after pushing a button and then I read
it right away.
Is it possible that the file is not available right away?

[Gondwana]

Documentation.