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https://github.com/luckyframework/carbon
Email library for Crystal. Testable, adapter-based, and catches bugs for you. Comes with an adapter for SendGrid.
https://github.com/luckyframework/carbon
crystal email
Last synced: about 2 months ago
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Email library for Crystal. Testable, adapter-based, and catches bugs for you. Comes with an adapter for SendGrid.
- Host: GitHub
- URL: https://github.com/luckyframework/carbon
- Owner: luckyframework
- License: mit
- Created: 2018-04-06T16:57:37.000Z (about 6 years ago)
- Default Branch: main
- Last Pushed: 2024-02-25T20:36:47.000Z (4 months ago)
- Last Synced: 2024-02-25T21:29:32.214Z (4 months ago)
- Topics: crystal, email
- Language: Crystal
- Homepage:
- Size: 293 KB
- Stars: 84
- Watchers: 8
- Forks: 18
- Open Issues: 12
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists
- awesome-crystal - carbon - Fun, testable, and adapter-based email library (Email)
- awesome-crystal - carbon - Fun, testable, and adapter-based email library (Email)
- awesome-crystal - carbon - Fun, testable, and adapter-based email library (Email)
README
# Carbon
[](https://luckyframework.github.io/carbon)
Email library written in Crystal.
## Installation
Add this to your application's `shard.yml`:
```yaml
dependencies:
carbon:
github: luckyframework/carbon
```
## Adapters
- `Carbon::SendGridAdapter`- See [luckyframework/carbon_sendgrid_adapter](https://github.com/luckyframework/carbon_sendgrid_adapter).
- `Carbon::SmtpAdapter` - See [luckyframework/carbon_smtp_adapter](https://github.com/luckyframework/carbon_smtp_adapter).
- `Carbon::AwsSesAdapter` - See [keizo3/carbon_aws_ses_adapter](https://github.com/keizo3/carbon_aws_ses_adapter).
- `Carbon::SendInBlueAdapter` - See [atnos/carbon_send_in_blue_adapter](https://github.com/atnos/carbon_send_in_blue_adapter).
- `Carbon::MailgunAdapter` - See [atnos/carbon_mailgun_adapter](https://github.com/atnos/carbon_mailgun_adapter).
- `Carbon::SparkPostAdapter` - See [Swiss-Crystal/carbon_sparkpost_adapter](https://github.com/Swiss-Crystal/carbon_sparkpost_adapter).
- `Carbon::PostmarkAdapter` - See [makisu/carbon_postmark_adapter](https://github.com/makisu/carbon_postmark_adapter).
- `Carbon::MailersendAdapter` - See [balakhorvathnorbert/carbon_mailersend_adapter](https://github.com/balakhorvathnorbert/carbon_mailersend_adapter).
## Usage
### First, create a base class for your emails
```crystal
require "carbon"
# You can setup defaults in this class
abstract class BaseEmail < Carbon::Email
# For example, set up a default 'from' address
from Carbon::Address.new("My App Name", "[email protected]")
# Use a string if you just need the email address
from "[email protected]"
end
```
### Configure the mailer class
```crystal
BaseEmail.configure do |settings|
settings.adapter = Carbon::DevAdapter.new(print_emails: true)
end
```
### Create a class for your email
```crystal
# Create an email class
class WelcomeEmail < BaseEmail
def initialize(@name : String, @email_address : String)
end
to @email_address
subject "Welcome, #{@name}!"
header "My-Custom-Header", "header-value"
reply_to "[email protected]"
# You can also do just `text` or `html` if you don't want both
templates text, html
end
```
### Create templates
Templates go in the same folder the email is in:
- Text email: `/templates//text.ecr`
- HTML email: `/templates//html.ecr`
So if your email class is in `src/emails/welcome_email.cr`, then your
templates would go in `src/emails/templates/welcome_email/text|html.ecr`.
```
# in /templates/welcome_email/text.ecr
# Templates have access to instance variables and methods in the email.
Welcome, <%= @name %>!
```
```
# in /templates/welcome_email/html.ecr
Welcome, <%= @name %>!
```
For more information on what you can do with Embedded Crystal (ECR), see [the official Crystal documentation](https://crystal-lang.org/api/latest/ECR.html).
### Template layouts
Layouts are optional allowing you to specify how each email template looks individually.
If you'd like to have the same layout on each, you can create a layout template in
`/templates//layout.ecr`
In this file, you'll yield the main email body with `<%= content %>`. Then in your `BaseEmail`, you can specify the name of the layout.
```crystal
abstract class BaseEmail < Carbon::Email
macro inherited
from default_from
layout :application_layout
end
end
```
```
# in src/emails/templates/application_layout/layout.ecr
Our Email
<%= content %>
footer
```
### Deliver the email
```
# Send the email right away!
WelcomeEmail.new("Kate", "[email protected]").deliver
# Send the email in the background using `spawn`
WelcomeEmail.new("Kate", "[email protected]").deliver_later
```
### Delay email delivery
The built-in delay uses the `deliver_later_strategy` setting set to `Carbon::SpawnStrategy`. You can create your own custom delayed strategy
that inherits from `Carbon::DeliverLaterStrategy` and defines a `run` method that takes a `Carbon::Email` and a block.
One example might be a job processor:
```crystal
# Define your new delayed strategy
class SendEmailInJobStrategy < Carbon::DeliverLaterStrategy
# `block.call` will run `deliver`, but you can call
# `deliver` yourself on the `email` when you need.
def run(email : Carbon::Email, &block)
EmailJob.perform_later(email)
end
end
class EmailJob < JobProcessor
def perform(email : Carbon::Email)
email.deliver
end
end
# configure to use your new delayed strategy
BaseEmail.configure do |settings|
settings.deliver_later_strategy = SendEmailInJobStrategy.new
end
```
## Testing
### Change the adapter
```crystal
# In spec/spec_helper.cr or wherever you configure your code
BaseEmail.configure do
# This adapter will capture all emails in memory
settings.adapter = Carbon::DevAdapter.new
end
```
### Reset emails before each spec and include expectations
```crystal
# In spec/spec_helper.cr
# This gives you the `be_delivered` expectation
include Carbon::Expectations
Spec.before_each do
Carbon::DevAdapter.reset
end
```
### Integration testing
```crystal
# Let's say we have a class that signs the user up and sends the welcome email
# that was described at the beginning of the README
class SignUpUser
def initialize(@name : String, @email_address : String)
end
def run
sign_user_up
WelcomeEmail.new(name: @name, email_address: @email_address).deliver
end
end
it "sends an email after the user signs up" do
SignUpUser.new(name: "Emily", email_address: "[email protected]").run
# Test that this email was sent
WelcomeEmail.new(name: "Emily", email_address: "[email protected]").should be_delivered
end
# or we can just check that some emails were sent
it "sends some emails" do
SignUpUser.new(name: "Emily", email_address: "[email protected]").run
Carbon.should have_delivered_emails
end
```
### Unit testing
Unit testing is simple. Instantiate your email and test the fields you care about.
```crystal
it "builds a nice welcome email" do
email = WelcomeEmail.new(name: "David", email_address: "[email protected]")
# Note that recipients are converted to an array of Carbon::Address
# So if you use a string value for the `to` field, you'll get an array of
# Carbon::Address instead.
email.to.should eq [Carbon::Address.new("[email protected]")]
email.text_body.should contain "Welcome"
email.html_body.should contain "Welcome"
end
```
> Note that unit testing can be superfluous in most cases. Instead, try
> unit testing just fields that have complex logic. The compiler will catch most
> other issues.
## Development
- `shards install`
- Make changes
- `./script/test`
- `./bin/ameba`
## Contributing
1. Fork it ( https://github.com/luckyframework/carbon/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Make your changes
4. Run `./script/test` to run the specs, build shards, and check formatting
5. Commit your changes (git commit -am 'Add some feature')
6. Push to the branch (git push origin my-new-feature)
7. Create a new Pull Request
## Contributors
- [paulcsmith](https://github.com/paulcsmith) Paul Smith - creator