Rust Actix-Web Example

This is a simple example of a Rust web application built using the Actix-Web framework. The application consists of two routes: an index page and a form submission page.

Usage

1. Setting up your SMTP and server credentials in .env file

2. Start the server:

   • cargo build
   • cargo run

NOTE: I recommend to use a cargo-watch for checking code changes. It will increase compiling time.

3. Open a web browser and navigate to <your domain> to view the index page.

4. Click the "Submit" button to go to the form submission page.

5. Enter some data into the form and click "Submit" to see the submitted data on the page.

Endpoints and code overview

• main() (EP: / ) function sets up the Actix-Web server and defines the two routes.
• index() (EP: /templates/index ) function handles requests to the root URL and renders the index.tera template using the Tera templating engine.
• form() (EP: /templates/form ) function handles form submissions and renders the form.tera template with the submitted data.

Form Process Module

This module contains the process_form function which processes form data and sends an email using the SMTP protocol.

Quick code description

The process_form function takes in a web::Form object containing a HashMap of form data. It then creates a new Tera context and inserts the name and context into it.

The SMTP server credentials are defined as static variables using the env::var function to retrieve their values from the .env file. These variables are SMTP_USER, SMTP_PASS, and SMTP_HOST.

The function then iterates over the form data and checks if any of the values are empty. If a value is empty, an error message is inserted into the context. If all values are non-empty, the function creates an email message using the Message::builder method and sends it using an SMTP transport.

The part of the code where you can change the sent message is where the email message is created using the Message::builder method. The part of the code where the SMTP credentials are declared is where the static variables SMTP_USER, SMTP_PASS, and SMTP_HOST are defined:

let SMTP_USER = env::var("SMTP_USER").expect("SMTP_USER must be set"); // get the SMTP_USER from the .env file
let SMTP_PASS = env::var("SMTP_PASS").expect("SMTP_PASS must be set"); // get the SMTP_PASS from the .env file
let SMTP_HOST = env::var("SMTP_HOST").expect("SMTP_HOST must be set"); // get the SMTP_HOST from the .env file | WITHOUT SSL:// OR TLS://!!!

These values will be readen from .env config file from program parent directory or root project dir.

Dependencies

This code uses the following dependencies:

• actix-web: for handling web requests and responses
• lettre: for sending emails via SMTP
• tera: for rendering templates

Code usage

1. Set the SMTP server and server credentials by replacing the values of the SMTP_SERVER, SMTP_USER, and SMTP_PASS, SERVER_IP static variables with your own (host should not include ssl:// or tls://):

SERVER_IP=127.0.0.1:8080
SMTP_USER=your_smtp_user
SMTP_PASS=your_smtp_pass
SMTP_HOST=your_smtp_host

2. The process_form function takes in a web::Form object containing form data as a key-value pair and returns an HttpResponse.
3. The function checks if the form data is empty and inserts an error message into the Tera context if it is.
4. The function iterates over the form data and checks if any value is empty. If a value is empty, an error message is inserted into the context and the iteration continues.
5. If all values are present, the function creates an email message using the Lettre crate and sends it using the provided SMTP server credentials.

Error handler

The error_handler module contains all possible (for my opinion) web errors, but if you want to modify it, here's how can you do this:

let response = match error.as_response_error().error_response().status() {
    StatusCode::<STATUS CODE> => {
        HttpResponse::BadRequest().json(json!({
             "error": "<error>",
             "message": <error_message>
        }))
    },
   // and some code below

Note that all of the StatusCode:: errors should be declared in let response = ... construction.

Form Configuration Module

This module provides a global form configuration and handler. It allows you to set and retrieve form data such as email, name, and message body. It also provides methods for validating email and non-empty input.

Usage

To use this module, you need to create an instance of FormConfigImpl:

use crate::form_config::{FormConfig, FormConfigImpl};
// ..
let mut form_config = FormConfigImpl::new();

You can retrieve the form data using the corresponding getter methods:

let email = form_config.email();
let name = form_config.name();
let message_body = form_config.message_body();

You can also access the SMTP configuration by calling the smtp_user, smtp_pass, and smtp_host methods.

The module also provides an input_validator method that returns a reference to a NonEmptyInputValidator instance, and an email_validator method that returns a reference to an EmailValidator instance.

Adding Custom Variables

To add custom variables to the form configuration, you can modify the FormConfigImpl struct and add new fields. You can then implement the corresponding setter and getter methods in the FormConfig trait and provide an implementation in the FormConfigImpl struct.

For example, to add a phone number field, you can do the following:

pub trait FormConfig {
    // ...
    fn set_phone(&mut self, phone: String);
    fn phone(&self) -> String;
}

pub struct FormConfigImpl {
    // ...
    phone: String,
}

impl FormConfig for FormConfigImpl {
    // ...
    fn set_phone(&mut self, phone: String) {
        self.phone = phone;
    }

    fn phone(&self) -> String {
        self.phone.clone()
    }
}

Note that adding config variables like SMS-service requires adding them as env. variables in .env file and you should change the const of default config to your own:

const DEFAULT_CONFIG: &str = 
r#"# !! LOCALHOST: 127.0.0.1:8080
# !! IP SHOULD BE DECLARED IN FORMAT IP:PORT
SERVER_IP=your_ip
SMTP_USER=your_smtp_user
SMTP_PASS=your_smtp_pass
SMTP_HOST=your_smtp_host
DATABASE_URL=postgres://user:password@host/database"#;
#some of your datas

Context

The FormConfigImpl struct also contains a context field that holds a Context instance from the tera crate. You can access and modify this context using the context method:

let mut context = form_config.context();
context.insert("key", "value");

This allows you to add custom data to the context that can be used when rendering templates.

Validation

The module provides two validators: an email validator and a non-empty input validator. You can access these validators using the email_validator and input_validator methods:

let email_validator = form_config.email_validator();
let input_validator = form_config.input_validator();

You can also then use these validators to validate form data:

let is_email_valid = email_validator.is_valid(&form_config.email());
let is_name_valid = input_validator.is_valid(&form_config.name());

Notes

• This code contains some debug messages that can be removed or commented out.
• The Tera template used to render the response is located in the templates/form.tera file.
• I have some TODO here

TODO:

Later I want to add an:

• authorization system
• the ability to upload files
• cookies; But this requires a lot of work. For example, I already have a files upload:

pub async fn upload(mut payload: Multipart) -> Result<HttpResponse, Error> {
    // iterate over the multipart fields and save each one to a file
    while let Ok(Some(field)) = payload.try_next().await {
        save_field(field).await?;
    }

    Ok(HttpResponse::Ok().into())
}
pub fn init<T>(app: App<T>) -> App<T>
where
    T: ServiceFactory<ServiceRequest, Config = (), Response = actix_web::dev::ServiceResponse, Error = actix_web::Error, InitError = ()>,
{
    app.route("/upload", web::post().to(upload))
}

But for now it gives a bunch of errors that I’m too lazy to solve, and the problem is traits. I’m not strong in Rust and I’m still a beginner, so it’s a bit difficult for me. There is also an option to connect to the database and serialize data via JSON now:

async fn get_data(query: web::Query<Query>) -> HttpResponse {
    // Retrieve data from database using the provided id
    let data = get_data_from_database(query.id).await;

    // Return data as a JSON response
    HttpResponse::Ok().json(data)
}
async fn get_data_from_database(id: i32) -> serde_json::Value {
    // Example data retrieval from database
    json!({
        "id": id,
        "name": "Example Data",
        "value": 42
    })
}

I think I will definitely add this later, but not now.

Credits

This code is based on the Actix-Web Getting Started guide and uses the Tera templating engine.