npm package: @kontakta/parse-mail-adapter
Description: Universal Mail Adapter for Parse Server, supports any email provider REST API, with localization and templates.
Author: Manuel Trezza
Latest version: 2.1.0-alpha.9

# Parse Server API Mail Adapter <!-- omit in toc -->

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---

The Parse Server API Mail Adapter enables Parse Server to send emails using any 3rd party API with built-in dynamic templates and localization.

## Transfer <!-- omit in toc -->

ℹ️ This repository has been tranferred to the Parse Platform Organization on May 15, 2022. Please update any links that you may have to this repository, for example if you cloned or forked this repository and maintain a remote link to this orginal repository, or if you are referencing a GitHub commit directly as your dependency.

---

# Content <!-- omit in toc -->

- [Installation](#installation)
- [Demo](#demo)
- [Configuration](#configuration)
- [Templates](#templates)
- [Placeholders](#placeholders)
    - [Password Reset and Email Verification](#password-reset-and-email-verification)
- [Localization](#localization)
- [Cloud Code](#cloud-code)
  - [Example](#example)
  - [Parameters](#parameters)
- [Supported APIs](#supported-apis)
  - [Providers](#providers)
    - [Example for Mailgun](#example-for-mailgun)
    - [Example for AWS Simple Email Service](#example-for-aws-simple-email-service)
  - [Custom API](#custom-api)
- [Need help?](#need-help)

# Installation

1. Install adapter:
    ```
    npm install --save parse-server-api-mail-adapter
    ```
2. Add [template files](#templates) to a subdirectory.
2. Add [adapter configuration](#configuration) to Parse Server.

# Demo

The demo script makes it easy to test adapter configurations and templates by sending emails without Parse Server via the email service provider [Mailgun](https://www.mailgun.com):

1. Create a file `mailgun.json` in the `demo` directory with the following content:
    ```js
    {
        "key": "MAILGUN_API_KEY", // e.g. abc123
        "domain": "MAILGUN_DOMAIN", // e.g. sandbox-example@mailgun.org
        "sender": "SENDER_EMAIL", // e.g. sender@example.com
        "recipient": "RECIPIENT_EMAIL" // e.g. recipient@example.com
    }
    ```
2. Run `node ./demo` to execute the script and send an email.

You can modify the script to use any other API you like or debug-step through the sending process to better understand the adapter internals.

# Configuration

An example configuration to add the API Mail Adapter to Parse Server could look like this:

```js
const Mailgun = require('mailgun.js');
const formData = require('form-data');
const { ApiPayloadConverter } = require('parse-server-api-mail-adapter');

// Configure mail client
const mailgun = new Mailgun(formData);
const mailgunClient = mailgun.client({ username: 'api', key: process.env.MAILGUN_API_KEY });
const mailgunDomain = process.env.MAILGUN_DOMAIN;

// Configure Parse Server
const server = new ParseServer({
    ...otherServerOptions,

    emailAdapter: {
        module: 'parse-server-api-mail-adapter',
        options: {
            // The email address from which emails are sent.
            sender: 'sender@example.com',
            // The email templates.
            templates: {
                // The template used by Parse Server to send an email for password
                // reset; this is a reserved template name.
                passwordResetEmail: {
                    subjectPath: './files/password_reset_email_subject.txt',
                    textPath: './files/password_reset_email.txt',
                    htmlPath: './files/password_reset_email.html'
                },
                // The template used by Parse Server to send an email for email
                // address verification; this is a reserved template name.
                verificationEmail: {
                    subjectPath: './files/verification_email_subject.txt',
                    textPath: './files/verification_email.txt',
                    htmlPath: './files/verification_email.html'
                },
                // A custom email template that can be used when sending emails
                // from Cloud Code; the template name can be chosen freely; it
                // is possible to add various custom templates.
                customEmail: {
                    subjectPath: './files/custom_email_subject.txt',
                    textPath: './files/custom_email.txt',
                    htmlPath: './files/custom_email.html',
                    // Placeholders are filled into the template file contents.
                    // For example, the placeholder `{{appName}}` in the email
                    // will be replaced the value defined here.
                    placeholders: {
                        appName: "ExampleApp"
                    },
                    // Extras to add to the email payload that is accessible in the
                    // `apiCallback`.
                    extra: {
                        replyTo: 'no-reply@example.com'
                    },
                    // A callback that makes the Parse User accessible and allows
                    // to return user-customized placeholders that will override
                    // the default template placeholders. It also makes the user
                    // locale accessible, if it was returned by the `localeCallback`,
                    // and the current placeholders that will be augmented.
                    placeholderCallback: async ({ user, locale, placeholders }) => {
                        return {
                            phone: user.get('phone');
                        };
                    },
                    // A callback that makes the Parse User accessible and allows
                    // to return the locale of the user for template localization.
                    localeCallback: async (user) => {
                        return user.get('locale');
                    }
                }
            },
            // The asynchronous callback that contains the composed email payload to
            // be passed on to an 3rd party API and optional meta data. The payload
            // may need to be converted specifically for the API; conversion for
            // common APIs is conveniently available in the `ApiPayloadConverter`.
            // Below is an example for the Mailgun client.
            apiCallback: async ({ payload, locale }) => {
                const mailgunPayload = ApiPayloadConverter.mailgun(payload);
                await mailgunClient.messages.create(mailgunDomain, mailgunPayload);
            }
        }
    }
});
```

# Templates

Emails are composed using templates. A template defines the paths to its content files, for example:

```js
templates: {
    exampleTemplate: {
        subjectPath: './files/custom_email_subject.txt',
        textPath: './files/custom_email.txt',
        htmlPath: './files/custom_email.html',
    }
},
```

There are different files for different parts of the email:
- subject (`subjectPath`)
- plain-text content (`textPath`)
- HTML content (`htmlPath`)

See the [templates](https://github.com/parse-community/parse-server-api-mail-adapter/tree/main/spec/templates) for examples how placeholders can be used.

# Placeholders
Placeholders allow to dynamically insert text into the template content. The placeholder values are filled in according to the key-value definitions returned by the placeholder callback in the adapter configuration.

This is using the [mustache](http://mustache.github.io/mustache.5.html) template syntax. The most commonly used tags are:
- `{{double-mustache}}`: The most basic form of tag; inserts text as HTML escaped by default.
- `{{{triple-mustache}}}`: Inserts text with unescaped HTML, which is required to insert a URL for example.

### Password Reset and Email Verification

By default, the following placeholders are available in the password reset and email verification templates:
- `{{appName}}`: The app name as set in the Parse Server configuration.
- `{{username}}`: The username of the user who requested the email.
- `{{link}}`: The URL to the Parse Server endpoint for password reset or email verification.

# Localization

Localization allows to use a specific template depending on the user locale. To turn on localization for a template, add a `localeCallback` to the template configuration.

The locale returned by `localeCallback` will be used to look for locale-specific template files. If the callback returns an invalid locale or nothing at all (`undefined`), localization will be ignored and the default files will be used.

The locale-specific files are placed in sub-folders with the name of either the whole locale (e.g. `de-AT`), or only the language (e.g. `de`). The locale has to be in format `[language]-[country]` as specified in [IETF BCP 47](https://tools.ietf.org/html/bcp47), e.g. `de-AT`.

Localized files are placed in sub-folders of the given path, for example:
```js
base/
├── example.html         // default file
└── de/                  // de language folder
│   └── example.html     // de localized file
└── de-AT/               // de-AT locale folder
│   └── example.html     // de-AT localized file
```

Files are matched with the user locale in the following order:
1. **Locale** (locale `de-AT` matches file in folder `de-AT`)
2. **Language** (locale `de-AT` matches file in folder `de` if there is no file in folder `de-AT`)
3. **Default** (default file in base folder is returned if there is no file in folders `de-AT` and `de`)

# Cloud Code

Sending an email directly from Cloud Code is possible since Parse Server > 4.5.0. This adapter supports this convenience method.

## Example

If the `user` provided has an email address set, it is not necessary to set a `recipient` because the mail adapter will by default use the mail address of the `user`.

```js
Parse.Cloud.sendEmail({
  templateName: "next_level_email",
  placeholders: { gameScore: 100, nextLevel: 2 },
  user: parseUser // user with email address
});
```

## Parameters

| Parameter      | Type         | Optional | Default Value | Example Value               | Description                                                                                    |
|----------------|--------------|----------|---------------|-----------------------------|------------------------------------------------------------------------------------------------|
| `sender`       | `String`     |          | -             | `from@example.com`          | The email sender address; overrides the sender address specified in the adapter configuration. |
| `recipient`    | `String`     |          | -             | `to@example.com`            | The email recipient; if set overrides the email address of the `user`.                         |
| `subject`      | `String`     |          | -             | `Welcome`                   | The email subject.                                                                             |
| `text`         | `String`     |          | -             | `Thank you for signing up!` | The plain-text email content.                                                                  |
| `html`         | `String`     | yes      | `undefined`   | `<html>...</html>`          | The HTML email content.                                                                        |
| `templateName` | `String`     | yes      | `undefined`   | `customTemplate`            | The template name.                                                                             |
| `placeholders` | `Object`     | yes      | `{}`          | `{ key: value }`            | The template placeholders.                                                                     |
| `extra`        | `Object`     | yes      | `{}`          | `{ key: value }`            | Any additional variables to pass to the mail provider API.                                     |
| `user`         | `Parse.User` | yes      | `undefined`   | -                           | The Parse User that the is the recipient of the email.                                         |

# Supported APIs

This adapter supports any REST API by adapting the API payload in the adapter configuration `apiCallback` according to the API specification.

## Providers

For convenience, support for common APIs is already built into this adapter and available via the `ApiPayloadConverter`. The following is a list of currently supported API providers:

- [Mailgun](https://www.mailgun.com)
- [AWS Simple Email Service (AWS JavaScript SDK v3)](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-ses/index.html)

If the provider you are using is not already supported, please feel free to open a PR.

### Example for Mailgun

This is an example for the Mailgun client:

```js
// Configure mail client
const mailgun = require('mailgun.js');
const mailgunClient = mailgun.client({ username: 'api', key: process.env.MAILGUN_API_KEY });
const mailgunDomain = process.env.MAILGUN_DOMAIN;

// Configure Parse Server
const server = new ParseServer({
    ...otherServerOptions,

    emailAdapter: {
        module: 'parse-server-api-mail-adapter',
        options: {
            ... otherAdapterOptions,

            apiCallback: async ({ payload, locale }) => {
                const mailgunPayload = ApiPayloadConverter.mailgun(payload);
                await mailgunClient.messages.create(mailgunDomain, mailgunPayload);
            }
        }
    }
});
```

### Example for AWS Simple Email Service

This is an example for the AWS Simple Email Service client using the AWS JavaScript SDK v3:

```js
// Configure mail client
const { SES, SendEmailCommand } = require('@aws-sdk/client-ses');

const {
  fromInstanceMetadata, // Get credentials via IMDS from the AWS instance (when deployed on AWS instance)
  fromEnv, // Get AWS credentials from environment variables (when testing locally)
} = require('@aws-sdk/credential-providers');

// Get AWS credentials depending on environment
const credentialProvider= process.env.NODE_ENV == 'production' ? fromInstanceMetadata() : fromEnv();
const credentials = await credentialProvider();

const sesClient = new SES({
    credentials,
    region: 'eu-west-1',
    apiVersion: '2010-12-01'
});

// Configure Parse Server
const server = new ParseServer({
    ...otherServerOptions,

    emailAdapter: {
        module: 'parse-server-api-mail-adapter',
        options: {
            ... otherAdapterOptions,

            apiCallback: async ({ payload, locale }) => {
                const awsSesPayload = ApiPayloadConverter.awsSes(payload);
                const command = new SendEmailCommand(awsSesPayload);
                await sesClient.send(command);
            }
        }
    }
});
```

## Custom API

This is an example of how the API payload can be adapted in the adapter configuration `apiCallback` according to a custom email provider's API specification.

```js
// Configure mail client
const customMail = require('customMail.js');
const customMailClient = customMail.configure({ ... });

// Configure Parse Server
const server = new ParseServer({
    ...otherOptions,

    emailAdapter: {
        module: 'parse-server-api-mail-adapter',
        options: {
            ... otherOptions,

            apiCallback: async ({ payload, locale }) => {
                const customPayload = {
                    customFrom: payload.from,
                    customTo: payload.to,
                    customSubject: payload.subject,
                    customText: payload.text
                };
                await customMailClient.sendEmail(customPayload);
            }
        }
    }
});
```

# Need help?

- Ask on StackOverflow using the [parse-server](https://stackoverflow.com/questions/tagged/parse-server) tag.
- Search through existing [issues](https://github.com/parse-community/parse-server-api-mail-adapter/issues) or open a new issue.