whatsapp-web.js

# Handling Attachments

# Downloading Media

Sometimes your client may need to download and process media files that have been attached to messages it receives. This library includes some useful functions to download these files in base64 format.

You can detect which messages have attached media by checking its hasMedia property. Then, you can actually download the data by using downloadMedia method of a Message object:

client.on('message', async (msg) => {
    if (msg.hasMedia) {
        const media = await msg.downloadMedia();
        // do something with the media data here
    }
});

The downloadMedia function returns an object of type MessageMedia (opens new window). This will give you access to its mimetype, base64 data and filename, if specified.

IMPORTANT

You shouldn't assume that the download will be successful. In cases where the media is not able to be downloaded (for example, if the media has been deleted from the phone or can no longer be downloaded), the downloadMedia method will return undefined.

# Sending Media

You can easily send photos, audio, videos and gifs by using the library. To do this, you'll just need to construct a MessageMedia (opens new window) object, exactly like the one you get by downloading media. This requires the mimetype for the file you'll send, as well as a base64-encoded string representing the data:

const { MessageMedia } = require('whatsapp-web.js');

// client initialization...

client.on('message', async (msg) => {
    if (msg.body === '!send-media') {
        const media = new MessageMedia('image/png', base64Image);
        await client.sendMessage(msg.from, media);
    }
});

TIP

You can send a caption along with the file by specifying the caption option while sending the message:

// your code here...
await client.sendMessage(chatId, media, { caption: 'this is my caption' });

For more additional information, check available message send options (opens new window).

# Sending Local Files

If you're sending files from your computer, you can use a helper function to automatically read the file in base64, compute its mime type and get its filename:

const { MessageMedia } = require('whatsapp-web.js');

client.on('message', async (msg) => {
    if (msg.body === '!send-media') {
        const media = MessageMedia.fromFilePath('./path/to/image.png');
        await client.sendMessage(msg.from, media);
    }
});

# Sending Files from a URL

A similar helper function is also available for sending files based on a remote URL:

const { MessageMedia } = require('whatsapp-web.js');

client.on('message', async (msg) => {
    if (msg.body === '!send-media') {
        const media = await MessageMedia.fromUrl('https://via.placeholder.com/350x150.png');
        await client.sendMessage(msg.from, media);
    }
});

# Caveat for Sending Videos and GIFs

Whatsapp-web.js uses Puppeteer (opens new window), which comes bundled with the Chromium browser, an open source version of the popular Google Chrome browser. Since AAC and H.264 are licensed formats, they are not supported by Chromium. More info on this can be found on the Puppeteer documentation (opens new window).

Because of this, you'll need to point Puppeteer to use a separately installed Chrome browser if you intend to use this functionality. This can be done by passing the executablePath option to Puppeteer while creating the client:

const client = new Client({
    puppeteer: {
        executablePath: '/path/to/Chrome',
    }
})

The executablePath value will depend on your OS and install location for Chrome, but here are some defaults by OS:

  • macOS: /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
  • Windows: C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe
  • Linux: /usr/bin/google-chrome-stable

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