Introducing 'sparkpost' a Rust Crate for email API

[dependencies] sparkpost="0.4" serde_json="1.0" serde_derive = "1.0" serde = "1.0" chrono = { version = "0.4", features = ["serde"] } dotenv = "0.13" 

// main.rs #[macro_use] extern crate serde_derive; extern crate chrono; // for setting dateTime option to an email extern crate dotenv; // optional- to read api key from .env file extern crate serde; extern crate sparkpost; use chrono::prelude::*; use sparkpost::transmission::{ Attachment, EmailAddress, Message, Options, Recipient, Transmission, TransmissionResponse, }; // this could be any Type to replace vlaues in sparkpost template // only requirement is that it implements Serialize from serde #[derive(Debug, Serialize)] struct Data { name: String, } #[allow(unused)] fn get_api_key() -> String { use dotenv::dotenv; use std::env; dotenv().ok(); env::var("SPARKPOST_API_KEY").expect("SPARKPOST_API_KEY must be set") } fn main() { // for eu servers use  // let tm = Transmission::new_eu(get_api_key()); let tm = Transmission::new(get_api_key()); // new email message with sender name and email let mut email = Message::new(EmailAddress::new( "marketing@example.sink.sparkpostmail.com", "Example Company", )); let options = Options { open_tracking: true, click_tracking: true, transactional: false, sandbox: false, inline_css: false, start_time: Some(Utc.ymd(2019, 1, 1).and_hms(0, 0, 0)), }; // recipient with substitute data for the template let recipient = Recipient::with_substitution( EmailAddress::new("bob@company.com", "Bob"), Data { name: "Bob".into() }, ); let attachment = Attachment { file_type: "image/png".into(), name: "AnImage.png".into(), // data is base64 encoded string data: "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAAXNSR0IArs4c6QAAAAlwSFlzAAAmCC".into(), }; // complete the email message with details email .add_recipient(recipient) .add_attachment(attachment) .options(options) .campaign_id("marketing_blitz") .subject("My Awesome email 😎") .html("<h1>hello {name}</h1>") .text("hello {name}"); let result = tm.send(&email); match result { Ok(res) => { match res { TransmissionResponse::ApiResponse(api_res) => { println!("API Response: \n {:#?}", api_res); assert_eq!(1, api_res.total_accepted_recipients); assert_eq!(0, api_res.total_rejected_recipients); } TransmissionResponse::ApiError(errors) => { println!("Response Errors: \n {:#?}", &errors); } } } Err(error) => { println!("error \n {:#?}", error); } } }