Cornally/prod_audify_gateway_opengraph_processor

## prod_audify_gateway_opengraph_processor
"use strict";

const https = require("https");

// These UAs receive the special page for OpenGraph
const opengraphUAs = [
    'facebookexternalhit/1.1',
    'Twitterbot',
    'Googlebot',
    'Slack',
    'LinkedInBot/1.0',
    'Pinterest'
];

// This will work on Node 8.10 environment
function requestArticle(guid) {
    return new Promise((resolve) => {
        const options = {
            host : "api.audify.fm",
            port : "443",
            path : `/stream/${guid}?language=en`,
            headers : {
                "Content-Type" : "application/json"
            }
        };

        https.get(options, (res) => {
            res.setEncoding("utf8");
            let body = "";

            res.on("data", data => {
                body += data;
            });

            res.on("end", () => {
                body = JSON.parse(body);
                resolve(body.items[0]);
            });
        });
    });
}

async function fetchArticle(guid) {
    try {
        let response = await requestArticle(guid);
        return response;
    }
    catch(error) {
        return error;
    }
}

// Return full URL, 'https://app.audify.fm/article/something-title/:guid'
function getUrl(article, guid) {
    const readableTitle = article.title.replace(/[\W_]\s*$/, '').replace(/[\W_]+/g, '-').toLowerCase();
    return `https://app.audify.fm/article/${readableTitle}/${guid}`
}

// Generate resulting markup for clients being served OG.  Replace double-quotes with html entities to ensure
// tag values are not cut short if a double-quote exists in the field's value.  Add a prefix to summary and truncate
// to 240 words so we're not spilling the beans.
function getBodyHtml(data, ua, url, uri) {
  const title = data.title.replace(/"/g, "&quot;");
  const summary = 'TL;DR — ' + data.summary.replace(/^(.{240}[^\s]*).*/, "$1").replace(/"/g, "&quot;") + '…';
    return `<!DOCTYPE html>
       <html>
        <head>
          <!-- COMMON TAGS -->
          <meta charset="utf-8">
          <title>${data.title} - Audify.FM</title>

          <!-- Search Engine -->
          <meta name="description" content="${summary}">
          <meta name="image" content="${data.image_url}">

          <!-- Schema.org for Google -->
          <meta itemprop="name" content="${title}">
          <meta itemprop="description" content="${summary}">
          <meta itemprop="image" content="${data.image_url}">

          <!-- Open Graph general (Facebook, Pinterest & Google+) -->
          <meta prefix="og: http://ogp.me/ns#" name="og:type" content="website">
          <meta prefix="og: http://ogp.me/ns#" name="og:audio" content="${data.audio_url}" />
          <meta prefix="og: http://ogp.me/ns#" name="og:title" content="${title}">
          <meta prefix="og: http://ogp.me/ns#" name="og:description" content="${summary}">
          <meta prefix="og: http://ogp.me/ns#" name="og:image" content="${data.image_url}">
          <meta prefix="og: http://ogp.me/ns#" name="og:url" content="${url}">
          <meta prefix="og: http://ogp.me/ns#" name="og:site_name" content="${title}">
        </head>
        <body>
          <p>uri: ${uri}</p>
          <p>agent: ${ua}</p>
          <p>name: ${title}</p>
          <p>description: ${summary} </p>
        </body>
     </html>`;
}

exports.handler = async (event, context, callback) => {
    const request = event.Records[0].cf.request;

    // Store user-agent of viewer request
    const requestUA = request.headers['user-agent'][0].value;

    const serveOpenGraphContent = !!opengraphUAs.find(ua => {
        if (requestUA.indexOf(ua) !== -1) return true;
    });

    // Uncomment for debugging
    console.log('serve opengraph content: ' + serveOpenGraphContent + ' to ' + requestUA);

    // If the request is not for an article, return early.
    const uri = request.uri;
    const splitUri = uri.split('/');
    if (!serveOpenGraphContent) {
        callback(null, request);
    }

    // Get article guid.  When split out, the guid is the third param in the URI, '/article/fake-title-here/:guid'
    const idx = splitUri.indexOf('article') + 2;
    const guid = splitUri[idx];

    // Fetch a single article
    let article = await fetchArticle(guid);

    // Get URL ... even though we have it in the original request
    const url = getUrl(article);

    // Generate resulting markup for OG-enabled UAs
    const body = getBodyHtml(article, requestUA, url, uri);

    const response = {
      status: '200',
      statusDescription: 'HTTP OK',
      body,
        headers: {
        'cache-control': [{
          key: 'Cache-Control',
          value: 'max-age=100'
         }],
        'content-type': [{
          key: 'Content-Type',
          value: 'text/html'
         }]
        }
    };

    return response;
};
	"use strict";

	const https = require("https");

	// These UAs receive the special page for OpenGraph
	const opengraphUAs = [
	'facebookexternalhit/1.1',
	'Twitterbot',
	'Googlebot',
	'Slack',
	'LinkedInBot/1.0',
	'Pinterest'
	];

	// This will work on Node 8.10 environment
	function requestArticle(guid) {
	return new Promise((resolve) => {
	const options = {
	host : "api.audify.fm",
	port : "443",
	path : `/stream/${guid}?language=en`,
	headers : {
	"Content-Type" : "application/json"
	}
	};

	https.get(options, (res) => {
	res.setEncoding("utf8");
	let body = "";

	res.on("data", data => {
	body += data;
	});

	res.on("end", () => {
	body = JSON.parse(body);
	resolve(body.items[0]);
	});
	});
	});
	}

	async function fetchArticle(guid) {
	try {
	let response = await requestArticle(guid);
	return response;
	}
	catch(error) {
	return error;
	}
	}

	// Return full URL, 'https://app.audify.fm/article/something-title/:guid'
	function getUrl(article, guid) {
	const readableTitle = article.title.replace(/[\W_]\s*$/, '').replace(/[\W_]+/g, '-').toLowerCase();
	return `https://app.audify.fm/article/${readableTitle}/${guid}`
	}

	// Generate resulting markup for clients being served OG. Replace double-quotes with html entities to ensure
	// tag values are not cut short if a double-quote exists in the field's value. Add a prefix to summary and truncate
	// to 240 words so we're not spilling the beans.
	function getBodyHtml(data, ua, url, uri) {
	const title = data.title.replace(/"/g, """);
	const summary = 'TL;DR — ' + data.summary.replace(/^(.{240}[^\s])./, "$1").replace(/"/g, """) + '…';
	return `<!DOCTYPE html>
	<html>
	<head>
	<!-- COMMON TAGS -->
	<meta charset="utf-8">
	<title>${data.title} - Audify.FM</title>

	<!-- Search Engine -->
	<meta name="description" content="${summary}">
	<meta name="image" content="${data.image_url}">

	<!-- Schema.org for Google -->
	<meta itemprop="name" content="${title}">
	<meta itemprop="description" content="${summary}">
	<meta itemprop="image" content="${data.image_url}">

	<!-- Open Graph general (Facebook, Pinterest & Google+) -->
	<meta prefix="og: http://ogp.me/ns#" name="og:type" content="website">
	<meta prefix="og: http://ogp.me/ns#" name="og:audio" content="${data.audio_url}" />
	<meta prefix="og: http://ogp.me/ns#" name="og:title" content="${title}">
	<meta prefix="og: http://ogp.me/ns#" name="og:description" content="${summary}">
	<meta prefix="og: http://ogp.me/ns#" name="og:image" content="${data.image_url}">
	<meta prefix="og: http://ogp.me/ns#" name="og:url" content="${url}">
	<meta prefix="og: http://ogp.me/ns#" name="og:site_name" content="${title}">
	</head>
	<body>
	<p>uri: ${uri}</p>
	<p>agent: ${ua}</p>
	<p>name: ${title}</p>
	<p>description: ${summary} </p>
	</body>
	</html>`;
	}

	exports.handler = async (event, context, callback) => {
	const request = event.Records[0].cf.request;

	// Store user-agent of viewer request
	const requestUA = request.headers['user-agent'][0].value;

	const serveOpenGraphContent = !!opengraphUAs.find(ua => {
	if (requestUA.indexOf(ua) !== -1) return true;
	});

	// Uncomment for debugging
	console.log('serve opengraph content: ' + serveOpenGraphContent + ' to ' + requestUA);

	// If the request is not for an article, return early.
	const uri = request.uri;
	const splitUri = uri.split('/');
	if (!serveOpenGraphContent) {
	callback(null, request);
	}

	// Get article guid. When split out, the guid is the third param in the URI, '/article/fake-title-here/:guid'
	const idx = splitUri.indexOf('article') + 2;
	const guid = splitUri[idx];

	// Fetch a single article
	let article = await fetchArticle(guid);

	// Get URL ... even though we have it in the original request
	const url = getUrl(article);

	// Generate resulting markup for OG-enabled UAs
	const body = getBodyHtml(article, requestUA, url, uri);

	const response = {
	status: '200',
	statusDescription: 'HTTP OK',
	body,
	headers: {
	'cache-control': [{
	key: 'Cache-Control',
	value: 'max-age=100'
	}],
	'content-type': [{
	key: 'Content-Type',
	value: 'text/html'
	}]
	}
	};

	return response;
	};