Struct Mailer 

pub struct Mailer { /* private fields */ }

The primary entry point for sending transactional email.

Mailer loads Markdown templates, performs variable substitution, renders HTML and plain-text bodies, applies a layout, and delivers the resulting message over SMTP.

Cloning is cheap (Arc-based) and shares the SMTP connection, template source, and preloaded layouts.

Construction

• Mailer::new — uses a FileSource (optionally cached) derived from EmailConfig::templates_path.
• Mailer::with_source — accepts any custom TemplateSource.
• Mailer::with_stub_transport — in-memory stub for tests (requires feature "test-helpers" or #[cfg(test)]).

Implementations

impl Mailer

pub fn new(config: &EmailConfig) -> Result<Self>

Create a new Mailer with the default FileSource.

If config.cache_templates is true, the file source is wrapped in a CachedSource with config.template_cache_size capacity.

Errors

Returns an error if the SMTP transport cannot be built (e.g., invalid host, mismatched credentials) or if the layouts directory cannot be read.

pub fn with_source( config: &EmailConfig, source: Arc<dyn TemplateSource>, ) -> Result<Self>

Create a new Mailer with a custom TemplateSource.

Use this to supply an in-memory source, a database-backed source, or any other custom implementation.

Errors

Returns an error if the SMTP transport cannot be built or if the layouts directory cannot be read.

pub fn render(&self, email: &SendEmail) -> Result<RenderedEmail>

Render a template without sending.

Performs variable substitution, parses the YAML frontmatter, converts the Markdown body to HTML (with button syntax support), applies the layout, and generates the plain-text fallback.

Returns a RenderedEmail containing the subject, HTML, and text.

Errors

Returns an error if the template cannot be loaded, the frontmatter is missing or malformed, or the requested layout is not found.

pub async fn send(&self, email: SendEmail) -> Result<()>

Render and send an email via SMTP.

Calls Self::render internally, then builds a multipart/alternative MIME message (text/plain + text/html) and delivers it over the configured transport.

Errors

Returns an error if the recipient list is empty, if any address is malformed, if the template cannot be rendered, or if the SMTP delivery fails.

Trait Implementations

impl Clone for Mailer

fn clone(&self) -> Mailer

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.