Ghost/ghost/email-service/lib/email-renderer.js
Simon Backx 8dfa490638
Added outbound link tagging for web posts (#16201)
fixes https://github.com/TryGhost/Team/issues/2433

- Moved all outbound link tagging code to separate OutboundLinkTagger
- Because a site can easily enable/disable this feature, we don't store
the ?refs in the HTML but add them on the fly for now in the Content
API.
2023-02-16 11:26:35 +01:00

685 lines
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/* eslint-disable no-unused-vars */
const logging = require('@tryghost/logging');
const fs = require('fs').promises;
const path = require('path');
const {isUnsplashImage, isLocalContentImage} = require('@tryghost/kg-default-cards/lib/utils');
const {Color, textColorForBackgroundColor, darkenToContrastThreshold} = require('@tryghost/color-utils');
const {DateTime} = require('luxon');
const htmlToPlaintext = require('@tryghost/html-to-plaintext');
/**
* @typedef {string|null} Segment
* @typedef {object} Post
* @typedef {object} Newsletter
*/
/**
* @typedef {object} MemberLike
* @prop {string} id
* @prop {string} uuid
* @prop {string} email
* @prop {string} name
*/
/**
* @typedef {object} ReplacementDefinition
* @prop {string} id
* @prop {RegExp} token
* @prop {(member: MemberLike) => string} getValue
*/
/**
* @typedef {object} EmailRenderOptions
* @prop {boolean} clickTrackingEnabled
*/
/**
* @typedef {object} EmailBody
* @prop {string} html
* @prop {string} plaintext
* @prop {ReplacementDefinition[]} replacements
*/
class EmailRenderer {
#settingsCache;
#settingsHelpers;
#renderers;
#imageSize;
#urlUtils;
#getPostUrl;
#storageUtils;
#handlebars;
#renderTemplate;
#linkReplacer;
#linkTracking;
#memberAttributionService;
#outboundLinkTagger;
#audienceFeedbackService;
/**
* @param {object} dependencies
* @param {object} dependencies.settingsCache
* @param {{getNoReplyAddress(): string, getMembersSupportAddress(): string}} dependencies.settingsHelpers
* @param {object} dependencies.renderers
* @param {{render(object, options): string}} dependencies.renderers.lexical
* @param {{render(object, options): string}} dependencies.renderers.mobiledoc
* @param {{getImageSizeFromUrl(url: string): Promise<{width: number}>}} dependencies.imageSize
* @param {{urlFor(type: string, optionsOrAbsolute, absolute): string, isSiteUrl(url, context): boolean}} dependencies.urlUtils
* @param {{isLocalImage(url: string): boolean}} dependencies.storageUtils
* @param {(post: Post) => string} dependencies.getPostUrl
* @param {object} dependencies.linkReplacer
* @param {object} dependencies.linkTracking
* @param {object} dependencies.memberAttributionService
* @param {object} dependencies.audienceFeedbackService
* @param {object} dependencies.outboundLinkTagger
*/
constructor({
settingsCache,
settingsHelpers,
renderers,
imageSize,
urlUtils,
storageUtils,
getPostUrl,
linkReplacer,
linkTracking,
memberAttributionService,
audienceFeedbackService,
outboundLinkTagger
}) {
this.#settingsCache = settingsCache;
this.#settingsHelpers = settingsHelpers;
this.#renderers = renderers;
this.#imageSize = imageSize;
this.#urlUtils = urlUtils;
this.#storageUtils = storageUtils;
this.#getPostUrl = getPostUrl;
this.#linkReplacer = linkReplacer;
this.#linkTracking = linkTracking;
this.#memberAttributionService = memberAttributionService;
this.#audienceFeedbackService = audienceFeedbackService;
this.#outboundLinkTagger = outboundLinkTagger;
}
getSubject(post) {
return post.related('posts_meta')?.get('email_subject') || post.get('title');
}
getFromAddress(_post, newsletter) {
let senderName = this.#settingsCache.get('title') ? this.#settingsCache.get('title').replace(/"/g, '\\"') : '';
if (newsletter.get('sender_name')) {
senderName = newsletter.get('sender_name');
}
let fromAddress = this.#settingsHelpers.getNoReplyAddress();
if (newsletter.get('sender_email')) {
fromAddress = newsletter.get('sender_email');
}
// For local development, rewrite the fromAddress to a proper domain
if (process.env.NODE_ENV !== 'production') {
if (/@localhost$/.test(fromAddress) || /@ghost.local$/.test(fromAddress)) {
const localAddress = 'localhost@example.com';
logging.warn(`Rewriting bulk email from address ${fromAddress} to ${localAddress}`);
fromAddress = localAddress;
}
}
return senderName ? `"${senderName}" <${fromAddress}>` : fromAddress;
}
/**
* @param {Post} post
* @param {Newsletter} newsletter
* @returns {string|null}
*/
getReplyToAddress(post, newsletter) {
if (newsletter.get('sender_reply_to') === 'support') {
return this.#settingsHelpers.getMembersSupportAddress();
}
return this.getFromAddress(post, newsletter);
}
/**
Returns all the segments that we need to render the email for because they have different content.
WARNING: The sum of all the returned segments should always include all the members. Those members are later limited if needed based on the recipient filter of the email.
@param {Post} post
@returns {Segment[]}
*/
getSegments(post) {
const allowedSegments = ['status:free', 'status:-free'];
const html = this.renderPostBaseHtml(post);
/**
* Always add free and paid segments if email has paywall card
*/
if (html.indexOf('<!--members-only-->') !== -1) {
// We have different content between free and paid members
return allowedSegments;
}
const cheerio = require('cheerio');
const $ = cheerio.load(html);
let allSegments = $('[data-gh-segment]')
.get()
.map(el => el.attribs['data-gh-segment']);
const segments = [...new Set(allSegments)].filter(segment => allowedSegments.includes(segment));
if (segments.length === 0) {
// No difference in email content between free and paid
return [null];
}
// We have different content between free and paid members
return allowedSegments;
}
renderPostBaseHtml(post) {
const postUrl = this.#getPostUrl(post);
let html;
if (post.get('lexical')) {
html = this.#renderers.lexical.render(
post.get('lexical'), {target: 'email', postUrl}
);
} else {
html = this.#renderers.mobiledoc.render(
JSON.parse(post.get('mobiledoc')), {target: 'email', postUrl}
);
}
return html;
}
/**
*
* @param {Post} post
* @param {Newsletter} newsletter
* @param {Segment} segment
* @param {EmailRenderOptions} options
* @returns {Promise<EmailBody>}
*/
async renderBody(post, newsletter, segment, options) {
let html = this.renderPostBaseHtml(post);
// We don't allow the usage of the %%{uuid}%% replacement in the email body (only in links and special cases)
// So we need to filter them before we introduce the real %%{uuid}%%
html = html.replace(/%%{uuid}%%/g, '{uuid}');
// Paywall and members only content handling
const isPaidPost = post.get('visibility') === 'paid' || post.get('visibility') === 'tiers';
const membersOnlyIndex = html.indexOf('<!--members-only-->');
const hasMembersOnlyContent = membersOnlyIndex !== -1;
let addPaywall = false;
if (isPaidPost && hasMembersOnlyContent) {
if (segment === 'status:free') {
// Add paywall
addPaywall = true;
// Remove the members-only content
html = html.slice(0, membersOnlyIndex);
}
}
const templateData = await this.getTemplateData({
post,
newsletter,
html,
addPaywall
});
html = await this.renderTemplate(templateData);
// Link tracking
if (options.clickTrackingEnabled) {
html = await this.#linkReplacer.replace(html, async (url) => {
// We ignore all links that contain %%{uuid}%%
// because otherwise we would add tracking to links that need to be replaced first
if (url.toString().indexOf('%%{uuid}%%') !== -1) {
return url.toString();
}
// Add newsletter source attribution
const isSite = this.#urlUtils.isSiteUrl(url);
if (isSite) {
// Add newsletter name as ref to the URL
url = this.#outboundLinkTagger.addToUrl(url, newsletter);
// Only add post attribution to our own site (because external sites could/should not process this information)
url = this.#memberAttributionService.addPostAttributionTracking(url, post);
} else {
// Add email source attribution without the newsletter name
url = this.#outboundLinkTagger.addToUrl(url);
}
// Add link click tracking
url = await this.#linkTracking.service.addTrackingToUrl(url, post, '--uuid--');
// We need to convert to a string at this point, because we need invalid string characters in the URL
const str = url.toString().replace(/--uuid--/g, '%%{uuid}%%');
return str;
});
}
// Juice HTML (inline CSS)
const juice = require('juice');
html = juice(html, {inlinePseudoElements: true});
// happens after inlining of CSS so we can change element types without worrying about styling
const cheerio = require('cheerio');
const $ = cheerio.load(html);
// force all links to open in new tab
$('a').attr('target', '_blank');
// convert figure and figcaption to div so that Outlook applies margins
$('figure, figcaption').each((i, elem) => !!(elem.tagName = 'div'));
// Remove/hide parts of the email based on segment data attributes
$('[data-gh-segment]').get().forEach((node) => {
// TODO: replace with NQL interpretation
if (node.attribs['data-gh-segment'] !== segment) {
$(node).remove();
} else {
// Getting rid of the attribute for a cleaner html output
$(node).removeAttr('data-gh-segment');
}
});
// Convert DOM back to HTML
html = $.html(); // () Fix for vscode syntax highlighter
// Replacement strings
const replacementDefinitions = this.buildReplacementDefinitions({html, newsletter});
// TODO: normalizeReplacementStrings (replace unsupported replacement strings)
// Convert HTML to plaintext
const plaintext = htmlToPlaintext.email(html);
// Fix any unsupported chars in Outlook
html = html.replace(/&apos;/g, '&#39;');
html = html.replace(/→/g, '&rarr;');
html = html.replace(//g, '&ndash;');
html = html.replace(/“/g, '&ldquo;');
html = html.replace(/”/g, '&rdquo;');
return {
html,
plaintext,
replacements: replacementDefinitions
};
}
/**
* @private
* createUnsubscribeUrl
*
* Takes a member and newsletter uuid. Returns the url that should be used to unsubscribe
* In case of no member uuid, generates the preview unsubscribe url - `?preview=1`
*
* @param {string} [uuid] post uuid
* @param {Object} [options]
* @param {string} [options.newsletterUuid] newsletter uuid
* @param {boolean} [options.comments] Unsubscribe from comment emails
*/
createUnsubscribeUrl(uuid, options = {}) {
const siteUrl = this.#urlUtils.urlFor('home', true);
const unsubscribeUrl = new URL(siteUrl);
unsubscribeUrl.pathname = `${unsubscribeUrl.pathname}/unsubscribe/`.replace('//', '/');
if (uuid) {
unsubscribeUrl.searchParams.set('uuid', uuid);
} else {
unsubscribeUrl.searchParams.set('preview', '1');
}
if (options.newsletterUuid) {
unsubscribeUrl.searchParams.set('newsletter', options.newsletterUuid);
}
if (options.comments) {
unsubscribeUrl.searchParams.set('comments', '1');
}
return unsubscribeUrl.href;
}
/**
* @private
* Note that we only look in HTML because plaintext and HTML are essentially the same content
* @returns {ReplacementDefinition[]}
*/
buildReplacementDefinitions({html, newsletter}) {
const baseDefinitions = [
{
id: 'unsubscribe_url',
getValue: (member) => {
return this.createUnsubscribeUrl(member.uuid, {newsletterUuid: newsletter.get('uuid')});
}
},
{
id: 'uuid',
getValue: (member) => {
return member.uuid;
}
},
{
id: 'first_name',
getValue: (member) => {
return member.name?.split(' ')[0];
}
}
];
// Now loop through all the definenitions to see which ones are actually used + to add fallbacks if needed
const EMAIL_REPLACEMENT_REGEX = /%%\{(.*?)\}%%/g;
const REPLACEMENT_STRING_REGEX = /^(?<recipientProperty>\w+?)(?:,? *(?:"|&quot;)(?<fallback>.*?)(?:"|&quot;))?$/;
function escapeRegExp(string) {
return string.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}
// Stores the definitions that we are actually going to use
const replacements = [];
let result;
while ((result = EMAIL_REPLACEMENT_REGEX.exec(html)) !== null) {
const [replacementMatch, replacementStr] = result;
// Did we already found this match and added it to the replacements array?
if (replacements.find(r => r.id === replacementStr)) {
continue;
}
const match = replacementStr.match(REPLACEMENT_STRING_REGEX);
if (match) {
const {recipientProperty, fallback} = match.groups;
const definition = baseDefinitions.find(d => d.id === recipientProperty);
if (definition) {
replacements.push({
id: replacementStr,
originalId: recipientProperty,
token: new RegExp(escapeRegExp(replacementMatch), 'g'),
getValue: fallback ? (member => definition.getValue(member) || fallback) : definition.getValue
});
}
}
}
// Now loop any replacements with possible invalid characters and replace them with a clean id
let counter = 1;
for (const replacement of replacements) {
if (replacement.id.match(/[^a-zA-Z0-9_]/)) {
counter += 1;
replacement.id = replacement.originalId + '_' + counter;
}
delete replacement.originalId;
}
return replacements;
}
async renderTemplate(data) {
if (this.#renderTemplate) {
return this.#renderTemplate(data);
}
this.#handlebars = require('handlebars');
// Helpers
this.#handlebars.registerHelper('if', function (conditional, options) {
if (conditional) {
return options.fn(this);
} else {
return options.inverse(this);
}
});
this.#handlebars.registerHelper('and', function () {
const len = arguments.length - 1;
for (let i = 0; i < len; i++) {
if (!arguments[i]) {
return false;
}
}
return true;
});
this.#handlebars.registerHelper('not', function () {
const len = arguments.length - 1;
for (let i = 0; i < len; i++) {
if (!arguments[i]) {
return true;
}
}
return false;
});
this.#handlebars.registerHelper('or', function () {
const len = arguments.length - 1;
for (let i = 0; i < len; i++) {
if (arguments[i]) {
return true;
}
}
return false;
});
// Partials
const cssPartialSource = await fs.readFile(path.join(__dirname, './email-templates/partials/', `styles.hbs`), 'utf8');
this.#handlebars.registerPartial('styles', cssPartialSource);
const paywallPartial = await fs.readFile(path.join(__dirname, './email-templates/partials/', `paywall.hbs`), 'utf8');
this.#handlebars.registerPartial('paywall', paywallPartial);
const feedbackButtonPartial = await fs.readFile(path.join(__dirname, './email-templates/partials/', `feedback-button.hbs`), 'utf8');
this.#handlebars.registerPartial('feedbackButton', feedbackButtonPartial);
// Actual template
const htmlTemplateSource = await fs.readFile(path.join(__dirname, './email-templates/', `template.hbs`), 'utf8');
this.#renderTemplate = this.#handlebars.compile(Buffer.from(htmlTemplateSource).toString());
return this.#renderTemplate(data);
}
/**
* Get email preheader text from post model
* @param {object} postModel
* @returns
*/
#getEmailPreheader(postModel) {
let plaintext = postModel.get('plaintext');
let customExcerpt = postModel.get('custom_excerpt');
if (customExcerpt) {
return customExcerpt;
} else {
if (plaintext) {
return plaintext.substring(0, 500);
} else {
return `${postModel.get('title')} `;
}
}
}
/**
* @private
*/
async getTemplateData({post, newsletter, html, addPaywall}) {
let accentColor = this.#settingsCache.get('accent_color') || '#15212A';
let adjustedAccentColor;
let adjustedAccentContrastColor;
try {
adjustedAccentColor = accentColor && darkenToContrastThreshold(accentColor, '#ffffff', 2).hex();
adjustedAccentContrastColor = accentColor && textColorForBackgroundColor(adjustedAccentColor).hex();
} catch (e) {
logging.error(e);
accentColor = '#15212A';
}
const {href: headerImage, width: headerImageWidth} = await this.limitImageWidth(newsletter.get('header_image'));
const {href: postFeatureImage, width: postFeatureImageWidth} = await this.limitImageWidth(post.get('feature_image'));
const timezone = this.#settingsCache.get('timezone');
const publishedAt = (post.get('published_at') ? DateTime.fromJSDate(post.get('published_at')) : DateTime.local()).setZone(timezone).setLocale('en-gb').toLocaleString({
year: 'numeric',
month: 'short',
day: 'numeric'
});
let authors;
const postAuthors = await post.getLazyRelation('authors');
if (postAuthors?.models) {
if (postAuthors.models.length <= 2) {
authors = postAuthors.models.map(author => author.get('name')).join(' & ');
} else {
authors = `${postAuthors.models[0].get('name')} & ${postAuthors.models.length - 1} others`;
}
}
const postUrl = this.#getPostUrl(post);
// Signup URL is the post url with a hash added to it
const signupUrl = new URL(postUrl);
signupUrl.hash = `/portal/signup`;
// Audience feedback
const positiveLink = this.#audienceFeedbackService.buildLink(
'--uuid--',
post.id,
1
).href.replace('--uuid--', '%%{uuid}%%');
const negativeLink = this.#audienceFeedbackService.buildLink(
'--uuid--',
post.id,
0
).href.replace('--uuid--', '%%{uuid}%%');
const data = {
site: {
title: this.#settingsCache.get('title'),
url: this.#urlUtils.urlFor('home', true),
iconUrl: this.#settingsCache.get('icon') ?
this.#urlUtils.urlFor('image', {
image: this.#settingsCache.get('icon')
}, true) : null
},
preheader: this.#getEmailPreheader(post),
html,
post: {
title: post.get('title'),
url: postUrl,
authors,
publishedAt,
feature_image: postFeatureImage,
feature_image_width: postFeatureImageWidth,
feature_image_alt: post.related('posts_meta')?.get('feature_image_alt'),
feature_image_caption: post.related('posts_meta')?.get('feature_image_caption')
},
newsletter: {
name: newsletter.get('name')
},
//CSS
accentColor: accentColor, // default to #15212A
adjustedAccentColor: adjustedAccentColor || '#3498db', // default to #3498db
adjustedAccentContrastColor: adjustedAccentContrastColor || '#ffffff', // default to #ffffff
showBadge: newsletter.get('show_badge'),
headerImage,
headerImageWidth,
showHeaderIcon: newsletter.get('show_header_icon') && this.#settingsCache.get('icon'),
showHeaderTitle: newsletter.get('show_header_title'),
showHeaderName: newsletter.get('show_header_name'),
showFeatureImage: newsletter.get('show_feature_image') && !!postFeatureImage,
footerContent: newsletter.get('footer_content'),
classes: {
title: 'post-title' + (newsletter.get('title_font_category') === 'serif' ? ` post-title-serif` : ``) + (newsletter.get('title_alignment') === 'left' ? ` post-title-left` : ``),
titleLink: 'post-title-link' + (newsletter.get('title_alignment') === 'left' ? ` post-title-link-left` : ``),
meta: 'post-meta' + (newsletter.get('title_alignment') === 'left' ? ` post-meta-left` : ``),
body: newsletter.get('body_font_category') === 'sans_serif' ? `post-content-sans-serif` : `post-content`
},
// Audience feedback
feedbackButtons: newsletter.get('feedback_enabled') ? {
likeHref: positiveLink,
dislikeHref: negativeLink
} : null,
// Paywall
paywall: addPaywall ? {
signupUrl: signupUrl.href
} : null,
year: new Date().getFullYear().toString()
};
return data;
}
/**
* @private
* Sets and limits the width of an image + returns the width
* @returns {Promise<{href: string, width: number}>}
*/
async limitImageWidth(href) {
if (!href) {
return {
href,
width: 0
};
}
if (isUnsplashImage(href)) {
// Unsplash images have a minimum size so assuming 1200px is safe
const unsplashUrl = new URL(href);
unsplashUrl.searchParams.set('w', '1200');
return {
href: unsplashUrl.href,
width: 600
};
} else {
try {
const size = await this.#imageSize.getImageSizeFromUrl(href);
if (size.width >= 600) {
// keep original image, just set a fixed width
size.width = 600;
}
if (this.#storageUtils.isLocalImage(href)) {
// we can safely request a 1200px image - Ghost will serve the original if it's smaller
return {
href: href.replace(/\/content\/images\//, '/content/images/size/w1200/'),
width: size.width
};
}
return {
href,
width: size.width
};
} catch (err) {
// log and proceed. Using original header image without fixed width isn't fatal.
logging.error(err);
}
}
return {
href,
width: 0
};
}
}
module.exports = EmailRenderer;