aws lambda iot-update-handler signed s3 update file

iot-update-handler.js

'use strict';

var AWS = require('aws-sdk');

AWS.config.update({
    accessKeyId: process.env.S3_ACCESS_KEY_ID,
    secretAccessKey: process.env.S3_ACCESS_KEY_SECRET,
    region: 'us-east-1'
});

var s3 = new AWS.S3();

var supportedDevices = {
    "18:FE:AA:AA:AA:AA": "ah.m3u",
    "18:FE:34:A5:4E:56": {
        bucket: process.env.S3_BUCKET_NAME,
        latestFirmwareFilename: "httpUpdate.ino.bin"
    }
}

////[HTTP_USER_AGENT] => ESP8266-http-Update [HTTP_X_ESP8266_STA_MAC] => 18:FE:AA:AA:AA:AA [HTTP_X_ESP8266_AP_MAC] => 1A:FE:AA:AA:AA:AA [HTTP_X_ESP8266_FREE_SPACE] => 671744 [HTTP_X_ESP8266_SKETCH_SIZE] => 373940 [HTTP_X_ESP8266_CHIP_SIZE] => 524288 [HTTP_X_ESP8266_SDK_VERSION] => 1.3.0 [HTTP_X_ESP8266_VERSION] => DOOR-7-g14f53a19
var getRequestHandler = function(event, context, callback) {

    //Used in testing using query params
    if (!event.queryStringParameters ||
        !event.queryStringParameters.sketch ||
        !event.queryStringParameters.mac ||
        !supportedDevices[event.queryStringParameters.mac]
    ) {
        return callback(null, {
            statusCode: 403,
            body: JSON.stringify({ message: `Unsupported params` }),
            headers: {
                'Content-Type': 'application/json',
            }
        })
    }
    var sketchName = event.queryStringParameters.sketch;
    var deviceMacAddress = event.queryStringParameters.mac;
    var firmwareDetails = supportedDevices[event.queryStringParameters.mac];

    // if (!event.headers ||
    //     !event.headers["HTTP_X_ESP8266_VERSION"] ||
    //     !event.headers["HTTP_X_ESP8266_STA_MAC"] ||
    //     !supportedDevices[event.headers["HTTP_X_ESP8266_STA_MAC"]]
    // ) {
    //     return callback(null, {
    //         statusCode: 403,
    //         body: JSON.stringify({ message: `Unsupported params` }),
    //         headers: {
    //             'Content-Type': 'application/json',
    //         }
    //     })
    // }
    // var sketchName = event.headers["HTTP_X_ESP8266_VERSION"] ;
    // var deviceMacAddress = event.headers["HTTP_X_ESP8266_STA_MAC"];
    // var firmwareDetails = supportedDevices[event.headers["HTTP_X_ESP8266_STA_MAC"]];

    if (firmwareDetails.latestFirmwareFilename == sketchName) {
        var response = {
            statusCode: 304
        };

        return callback(null, response);
    }

    var options = {
        Bucket: firmwareDetails.bucket,
        Key: firmwareDetails.latestFirmwareFilename,
        Expires: 60
    };
    var url = s3.getSignedUrl('getObject', options);

    //testing
    var response = {
        statusCode: 200,
        headers: {
            'Content-Type': 'text/plain'
        },
        body: url
    };

    //Unfortunatly unsupported by esp, so using a "hack" to get the s3 url first then calling for the file.
    //https://github.com/esp8266/Arduino/issues/3811
    // var response = {
    //     statusCode: 301,
    //     headers: {
    //         "Location": url
    //     },
    //     body: null
    // };

    return callback(null, response);
};

exports.handler = (event, context, callback) => {
    console.log(event);
    if (event.httpMethod != 'GET') {
        return callback(null, {
            statusCode: 403,
            body: JSON.stringify({ message: `Unsupported method "${event.httpMethod}"` }),
            headers: {
                'Content-Type': 'application/json',
            }
        })
    }

    return getRequestHandler(event, context, callback);
};