cache-mailer

cache-mailer

Simple email sender with handlebars / ejs

Installation

$ npm install cache-mailer

Simple and easy way to register templates

cache-mailer provides a easy way to register teamplates by key and send emails with minimum required information.

const mailer = require('cache-mailer');

mailer.createTransport({
  host: "smtp.ethereal.email",
  port: 587,
  secure: false,
  auth: {
    user: ...,
    pass: ...,
  }
});

await mailer.registerTemplates([{
  key: 'signup',
  template: '<p>Dear {{user.name}},<br>...',
  subject: 'Welcome',
}, {
  key: 'checkout',
  template: '<p>Dear {{user.name}},<br>...',
  subject: 'Checked out',
}]);

await mailer.sendEmail({
  key: 'signup',
  receiver: '[e-mail]',
  sender: '[e-mail]'
});

Table of contents

• createTransport
• getTransport
• clearTransports
• registerTemplate
• registerTemplates
• sendMail
• sendEmail
• setLocals
• setOptions
• Express Middleware

---

createTransport

You can set node-mailer's SMTP transport options. (https://nodemailer.com/smtp/).

mailer.createTransport({
  host: "smtp.ethereal.email",
  port: 587,
  secure: false,
  auth: {
    user: ...,
    pass: ...,
  }
});

It also allows to create more than one transports by key.

mailer.createTransport('provider1', {
  host: "smtp.ethereal.email",
  port: 587,
  secure: false,
  auth: {
    user: ...,
    pass: ...,
  }
});

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---

getTransport

You can retrieve a mailer transport by its key.

const myTransport = mailer.getTransport('provider1');

It returns the default mailer transport if defined with empty key.

const defaultTransport = mailer.getTransport();

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---

clearTransports

It clears all registered mailer transports.

mailer.clearTransports();

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---

registerTemplate

registerTemplates

You can register template(s) by key in various ways.

• as template string
• as template path
• as async function returning a template string and a subject

This method takes single template or array of templates.

await mailer.registerTemplate({
  key: 'signup',
  template: '<p>Dear {{user.name}},<br>...',
  subject: 'Welcome',
});

await mailer.registerTemplates([{
  key: 'signup',
  template: '<p>Dear {{user.name}},<br>...',
  subject: 'Welcome',
}, {
  key: 'checkout',
  template: '<p>Dear {{user.name}},<br>...',
  subject: 'Checked out',
}]);

You can specify a template engine for each template. It will override the default template engine defined by 'setOptions' method.

await mailer.registerTemplate({
  key: 'invitation',
  template: '<p>Dear <%= user.name %>,<br>...',
  subject: 'Invitation to ...',
  templateEngine: 'ejs',
});

Register a template as a template string

await mailer.registerTemplate({
  key: 'signup',
  template: '<p>Dear {{user.name}},<br>...',
  subject: 'Welcome',
});

Register a template as a template path

The template path is an absolute path and using 'path.resolve' is a suggested way to get the path.

const path = require('path');

await mailer.registerTemplate({
  key: 'signup',
  templatePath: path.resolve('./signup.email.html'),
  subject: 'Welcome',
});

Register a template as a value function

The value function is expected to return both template and subject to cover a case of retrieving them from db. In case of db is the source of the templates, disable 'cache' option to get the current ones when sending emails.

await mailer.registerTemplate({
  key: 'signup',
  valueFn: () => Promise.resolve({ template: '<p>Dear {{user.name}},<br>...', subject: 'Welcome' }),
});

await mailer.registerTemplate({
  key: 'signup',
  valueFn: () => {
    const Template = mongoose.model('Template');
    return Template.findOne({ key: 'signup' }).then(({ template, subject }) => { template, subject });   
  }),
});

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---

sendMail

You can send an email directry without templating.

await mailer.sendMail({
  from: '[e-mail]', // sender address
  to: '[e-mail], [e-mail]', // list of receivers
  subject: 'Hello World!', // Subject line
  html: '<b>Hello There?</b>', // html body
  text: Hello There?, // plain text body; optional
});

'text' is an optional argument, and it will be derived from html string if omitted.

You can also send an email with a specific mailer transport.

const myTransport = mailer.getTransport('provider1');
await myTransport.sendMail({
  ...
});

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---

sendEmail

You can send an email by key with template data.

await mailer.sendEmail({
  key: 'signup',
  receiver: '[e-mail]',
  sender: '[e-mail]',
  data: { token: 'abcdefg' }
});

Before sending an email, subject and template html will be interpolated with data. (the below example use 'handlebars' syntax)

<p>You can find your link below.</p>
<a href="http://www.test.com/api/signup/{{token}}" target="_blank">Link</a>

will be interpolated with data { token: 'abcdefg' }

<p>You can find your link below.</p>
<a href="http://www.test.com/api/signup/abcdefg" target="_blank">Link</a>

You can also send an email with a specific mailer transport.

const myTransport = mailer.getTransport('provider1');
await myTransport.sendEmail({
  ...
});

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---

setLocals

You can set global template data to use in any email templates.

mailer.setLocals({ sender: '[e-mail]' });
await mailer.sendEmail({
  key: 'signup',
  receiver: '[e-mail]',
  data: { token: 'abcdefg' }
});

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---

setOptions

1. 'cache' option; defaults to false

• if true, it caches handlebar/ ejs instances created with subject and template html

• it won't update cached templates once cached, so in case of db changes, need to register the template again or just disable 'cache' option.

1. 'templateEngine' option; defaults to 'none' (no templating)

• cache-mailer supports two template engines for now; 'handlebars' and 'ejs'
• since 'handlebars' and 'ejs' are peer dependencies of cache-mailer, it is required to install one or both to set engine and interpolate templates.

mailer.setOptions({ cache: true, templateEngine: 'handlebars' });
await mailer.registerTemplate(...);

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Express Middleware

You can bind 'sendMail' and 'sendEmail' method to request instances and find request-specific data into the templates.

const app = express();

mailer.createTransport({...});
mailer.setOptions({...});
mailer.setLocals({...});

app.use(mailer({...})); // optional transport option to create one instead of using 'createTransport' method

await mailer.registerTemplate({
  key: 'request-send-email',
  template: '<p>Your requested path is {{req.path}}</p>',
  subject: 'Request Path',
});

app.get('/api/test/request-send-email', function(req, res, next) {
  req.sendEmail({
    key: 'request-send-email',
    receiver: '[e-mail]',
    sender: '[e-mail]'
  })
});

The request data you can find in a template are below:

• domain
• protocol
• hostname
• ip
• baseUrl
• originalUrl
• path
• body
• query
• params
• headers
• httpVersion

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MIT Licensed