IOTA API error when making send transaction call with Node.js client library

Question

I made some test codes to send transactions with Node.js client library, and received the below error response. I cannot find the cause of this error. Did this happen to anyone before? And can anyone explain what went wrong here?

Error: Request Error: Request too long
    at Object.requestError (/var/iota-node/node_modules/iota.lib.js/lib/errors/requestErrors.js:11:12)
    at makeRequest.prepareResult (/var/iota-node/node_modules/iota.lib.js/lib/utils/makeRequest.js:293:24)
    at exports.XMLHttpRequest.request.onreadystatechange (/var/iota-node/node_modules/iota.lib.js/lib/utils/makeRequest.js:71:25)
    at exports.XMLHttpRequest.dispatchEvent (/var/iota-node/node_modules/xmlhttprequest/lib/XMLHttpRequest.js:591:25)
    at setState (/var/iota-node/node_modules/xmlhttprequest/lib/XMLHttpRequest.js:610:14)
    at IncomingMessage.<anonymous> (/var/iota-node/node_modules/xmlhttprequest/lib/XMLHttpRequest.js:447:13)
    at emitNone (events.js:111:20)
    at IncomingMessage.emit (events.js:208:7)
    at endReadableNT (_stream_readable.js:1064:12)
    at _combinedTickCallback (internal/process/next_tick.js:138:11)

Codes I used to make transactions

    const IOTA = require('iota.lib.js');
    const fs=require("fs");

    const iota = new IOTA({ provider: 'http://iota.node.com:14265' })

    var content = fs.readFileSync("site.pdf", "base64");
    const trytes = 'MYADDRESS';
    var messageToSend = {
        'name': 'Test',
        'message': 'test message',
        'file_content': content
    }

    var messageStringified = JSON.stringify(messageToSend);
    var message = iota.utils.toTrytes(messageStringified);
    var tag = iota.utils.toTrytes('testtag');

    const transfers = [
        {
            value: 0,
            address: trytes,
            message: message,
            tag: tag
        }
    ];

    iota.api.sendTransfer(trytes, 3, 14, transfers, (error, success) => {
        if (error) {
            console.log(error)
        } else {
            console.log(success)
        }
    });

Answer 1

It seems to be a client error, because of a large request size. Besides, publishing large files as transactions requires a large amount of Proof-of-Work, which may take time or cause the connection to close depending on remote node settings. It might be a good idea to split file contents into multiple chunks and attach to tangle in a more granular manner.