ext-send-chunked-message

A library enabling the transmission of large messages via chrome.runtime in Chrome Extensions with Manifest V3.

Standard chrome.runtime.sendMessage has a message size limit ~32Mb. When you exceed the limit you will receive an error "Uncaught Error: Message length exceeded maximum allowed length". This library resolves the problem and allows you to send messages without a limit.

Installation

npm i ext-send-chunked-message

Usage - send large message from content script to backround:

content.js:

import { sendChunkedMessage } from 'ext-send-chunked-message'

sendChunkedMessage(largeMessage)
    .then(response => {
        // response received, can be either normal or large in size
        ...
    })

Usage - receive large message on background and send normal (unchunked) response

background.js:

import { addOnChunkedMessageListener } from 'ext-send-chunked-message'

addOnChunkedMessageListener((message, sender, sendResponse) => {
    // "message" is a large message, received in chunks and restored

    const normalResponse = ...;

    sendResponse(normalResponse);

    // return true for async listener
})

Usage - receive large message on background and send large response

background.js:

import { addOnChunkedMessageListener, sendChunkedResponse } from 'ext-send-chunked-message'

addOnChunkedMessageListener((message, sender, sendResponse) => {
    // "message" is a large message, received in chunks and restored

    const largeResponse = ...;

    sendChunkedResponse({
        sendMessageFn: message =>
            chrome.tabs.sendMessage(sender.tab.id, message)
    })(largeResponse, sendResponse);

    return true; // async listener
})

Supported environment variables

EXT_SEND_CHUNKED_MESSAGE_MAX_CHUNK_SIZE - max chunk size in bytes. Default is 32 * 1024 * 1024 (32Mb)

Examples

See Example README

Author

Alexey Belozerov alex@welldonecode.com