zotero-api-client-upload-override-example.js

const api = require('zotero-api-client'); // >= 0.36.0
const fs = require('fs');
const SparkMD5 = require('spark-md5');

const filedata1 = fs.readFileSync('picture-v1.jpg');
const filedata2 = fs.readFileSync('picture-v2.jpg');

const APIKEY = '';
const USERID = '';
const ITEM_KEY = '';

(async () => {
	try {
		// get attachment item template
		const template = (await api()
			.template('attachment')
			.get({ linkMode: 'imported_file' })).getData();
		
		console.log('template', template);
		
		// create attachment item
		const item = {
			...template,
			title: 'attached picture will override',
			parentItem: ITEM_KEY,
			filename: 'picture.jpg',
			contentType: 'image/jpeg',
		};
		const attachmentItem = (await api(APIKEY)
			.library(USERID)
			.items()
			.post([item])).getEntityByIndex(0);

		console.log('attachmentItem', attachmentItem);

		// upload first version of the file
		const response1 = await api(APIKEY)
			.library(USERID)
			.items(attachmentItem.key)
			.attachment('picture.jpg', filedata1.buffer)
			.post();

		console.log(response1);


		// calculate checksum of the first attachment file
		const md5sum = SparkMD5.ArrayBuffer.hash(filedata1.buffer);

		// upload second version of the file overriding previous one
		const response2 = await api(APIKEY)
			.library(USERID)
			.items(attachmentItem.key)
			.attachment('picture.jpg', filedata2.buffer, null, md5sum)
			.post();

		console.log(response2);

	} catch(e) {
		console.warn(e, e.reason, e.message, e.options);
	}
})();