feat: make isViewOnce messages downloadable

[alechkos]

PR Details

Make isViewOnce messages downloadable.

Description

The PR makes isViewOnce messages (image, video and ptt) downloadable.
Works for messages sent from both the web client and mobile.

Related Issue

closes #3275

How Has This Been Tested

const fs = require('fs');

// client initialization...

client.on('message', async (msg) => {
    if (msg._data.isViewOnce) {
        const media = await msg.downloadMedia();

        fs.writeFileSync(
            `${msg.type === 'image'
                ? `./image-${Date.now()}.png`
                : msg.type === 'video'
                    ? `./video-${Date.now()}.mp4`
                    : `./ptt-${Date.now()}.mp3`}`,
            Buffer.from(media.data, 'base64')
        );
    }
}

You can try the feature by running one of the following commands:

• NPM

npm install github:alechkos/whatsapp-web.js#downloadable-view-once-msgs

• YARN

yarn add github:alechkos/whatsapp-web.js#downloadable-view-once-msgs

Types of changes

• Dependency change
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• I have updated the documentation accordingly (index.d.ts).
• I have updated the usage example accordingly (example.js)

[rafaelsupport]

it worked for me
thx a lot

[alexduca]

Thank you so much for this!
But i have some problems with video.

This is my code:

...
var path_contact = 'path/to/folder/';
const media = await message.downloadMedia();
const mediaBufferData = Buffer.from(media.data, 'base64');
		    
if(message.type === 'image'){
    var mediaPatchName = 'image-' + Date.now() + '.png';
    var mediaPath = path_contact+'/'+mediaPatchName;
} else if(message.type === 'video'){
    var mediaPatchName = 'video-' + Date.now() + '.mp4';
    var mediaPath = path_contact+'/'+mediaPatchName;
} else if(message.type === 'ptt'){
    var mediaPatchName = 'ptt-' + Date.now() + '.mp3';
    var mediaPath = path_contact+'/'+mediaPatchName;
}
fs.writeFileSync(mediaPath,mediaBufferData);
...

This save an .mp4 file but I cant open it, and if I open it i see nothing!

[alechkos]

@alexduca

This PR only makes view-once messages downloadable (like regular media messages), as they were before the WhatsApp patch.
If you have problems downloading the files, you'll need to figure out how to download them yourself.

I also tested all file types (images .png, videos .mp4 and audio (ptt) .mp3), and they all opened successfully. Maybe you have to check the sent file itself.

[opssemnik]

I can confirm it works until 2.3000.1017322261-alpha
Afterwards videos stop working as the above commented mentioned

Reverting to older wweb version works.

On this version, the video media does properly appear but fails to be decrypted, altough i am able to download the encrypted media just fine

The weird thing is photos still work, and the properties of the message are the same (aside from the different media types etc) - meaning - it does not miss any fields. , it just does not decrypt the media , so downloadMedia fails. The media body is sill a valid encrypted media url

Reverting to older wweb version fixes the videos