handler.js

'use strict';

const execFile = require('child_process').execFile;
const fs = require('fs');

var config = {
    default_timeoutms : process.env.default_timeoutms || 29000,
    default_preloadevaldelayms : process.env.default_preloadevaldelayms || 10,
    default_preloaddelayms : process.env.default_preloaddelayms || 100,
    default_evaldelayms : process.env.defaulteval_delayms || 10,
    default_iframescrolldelayms : process.env.default_iframescrolldelayms || 50,
    default_delayms : process.env.default_delayms || 100,
    default_width : process.env.default_width || 1280,
    default_height : process.env.default_height || 1024,
    required_secret : process.env.required_secret || 'none',
};

module.exports.config = config;

module.exports.get = (event, context, callback) => {
    let data = event.queryStringParameters || {};
    const errorcb = function( code, message ) {
        callback(null, { statusCode: code, body: message, headers: { "Content-Type" : "text/plain" } } );
    }

    if ( ! data.url ) {
        return errorcb( 400, 'Missing url' );
    }
    if ( config.required_secret && config.required_secret != 'none' ) {
        if ( ! data.secret || config.required_secret != data.secret ) {
            return errorcb( 401, 'Wrong secret' );
        }
    }

    const tmpfilename = new Date().getTime();

    const opts = {
        preloadurl : data.preloadurl || '',
        preloadevalcode : data.preloadevalcode || '',
        preloadevaldelay : data.preloadevaldelayms || config.default_preloadevaldelayms || 0,
        preloaddelay : data.preloaddelayms || config.default_preloaddelayms || 0,
        url : data.url,
        file : `/tmp/${tmpfilename}.png`,
        width : data.width || config.default_width || 1280,
        height : data.height || config.default_height || 1024,
        clip : data.clip || '',
        clipheight : data.clipheight || 0,
        clipwidth : data.clipwidth || 0,
        cliptop : data.cliptop || 0,
        clipleft : data.clipleft || 0,
        clipwithiframe : data.clipwithiframe || '',
        iframescrollto : data.iframescrollto || 0,
        iframescrolldelay : data.iframescrolldelayms || config.default_iframescrolldelayms || 0,
        evalcode : data.evalcode || '',
        evaldelay : data.evaldelayms || config.default_evaldelayms || 0,
        delay : data.delayms || config.default_delayms || 0,
        timeout : data.timeoutms || config.default_timeoutms || 29000,
    }

    let childProcess;
    let timeoutHandler;

    timeoutHandler = setTimeout( function() {
        timeoutHandler = false;
        if ( childProcess ) {
            childProcess.kill();
        }
    }, parseInt( opts.timeout ) );

    childProcess = execFile( __dirname + '/phantomjs/phantomjs-2.1.1-linux-x86_64', ['--ignore-ssl-errors=true', __dirname + '/phantomscript.js', JSON.stringify(opts) ], { timeout : parseInt( opts.timeout ) }, (error, stdout, stderr) => {
        childProcess = false;
        if ( ! timeoutHandler ) {
            return errorcb( 408, 'ERROR: Timeout of '+ opts.timeout +"ms exceeded\n\nSTDERR:\n\n" + error + "\n\nSTDOUT:\n\n" + stdout );
        }

        clearTimeout( timeoutHandler );

        if ( error ) {
            return errorcb( 500, error + "\n\nSTDOUT:\n\n" + stdout );
        }
        else {
            const fb = fs.readFileSync( opts.file );
            return callback(null, { statusCode: 200, body: fb.toString('base64'), isBase64Encoded: true, headers: { "Content-Type" : "image/png" } } );
        }
    } );
};