camera-event-broker/index.ts

import {HttpRequest} from "@aws-sdk/protocol-http";
import {S3RequestPresigner} from "@aws-sdk/s3-request-presigner";
import {parseUrl} from "@aws-sdk/url-parser";
import {Hash} from "@aws-sdk/hash-node";
import {fromEnv} from "@aws-sdk/credential-provider-env";
import {formatUrl} from "@aws-sdk/util-format-url";

// Minio set-up variables
const minioSchema = process.env.MINIO_SCHEMA;
const minioHostname = process.env.MINIO_HOSTNAME;
const minioPort = process.env.MINIO_PORT;
const minioBucket = process.env.MINIO_BUCKET;

const signer = async function (asset: string) {
    const baseUrl = minioSchema + '://' + minioHostname + ((minioPort === '443' || minioPort === '80') ? '' : `:${minioPort}`)
     + '/' + minioBucket + '/'
    const s3ObjectUrl = parseUrl(baseUrl + asset);
    const presigner = new S3RequestPresigner({
        credentials: fromEnv(), // AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are read here.
        region: 'us-east-1',
        sha256: Hash.bind(null, "sha256"), // In Node.js
    });
    // Create a GET request from S3 url.
    return await presigner.presign(new HttpRequest(s3ObjectUrl));
}

const shots = 5
const reduceScreenshots = function (screenshots: Array<any>) {
    if (screenshots.length <= shots)
        return screenshots
    else
        var sc = []
        for (let i = 0; i < shots; i++) {
            sc.push(screenshots[i * Math.floor((screenshots.length - 1) / (shots - 1))])
        }
        return sc
}

const getScreenshots = async function (resp: object, path: string): Promise<any> {
    const screenshots = resp.screenshots ? resp.screenshots : []
    if (path === '/details/') {
        return screenshots.map(async (x) => {
            return {
                thumb: formatUrl(await signer(`thumb/${x}`)),
                orig: formatUrl(await signer(`${x}`))
            }
        });
    } else if (path === '/initial/' || path === '/query/' || path === '/streaming/') {
        return reduceScreenshots(screenshots).map(async (x) => {
            return {
                thumb: formatUrl(await signer(`thumb/${x}`)),
            }
        });
    }
}

export default {
    port: 3000,
    async fetch(request: Request) {
        await new Promise((r) => setTimeout(r, 1)); // https://github.com/oven-sh/bun/issues/1600
        let reqUrl = await parseUrl(request.url)
        let req = await request.json();

        return Promise.all(await getScreenshots(req, reqUrl.path)).then((r) => {
            let resp = Object.assign({}, req)
            resp.screenshots = r
            return resp
        }).then((resp) => {
            return new Response(JSON.stringify(resp))
        });
    },
};