bugfix parsing empty string and sending singlepart plaintext emails

crates/web-form/src/main.rs

@@ -5,37 +5,62 @@ use axum::{
     Extension, Form, Router,
 };
 
-use lettre::message::Mailbox;
+use lettre::message::{header::ContentType, Mailbox, SinglePart};
 use lettre::transport::smtp::AsyncSmtpTransport;
 use lettre::{AsyncTransport, Message, Tokio1Executor};
-use serde::Deserialize;
+use serde::{Deserialize, Deserializer};
 use std::error::Error;
 use std::net::SocketAddr;
 use std::sync::Arc;
 
+fn deserialize_empty_string_as_none<'de, D, T>(de: D) -> Result<Option<T>, D::Error>
+where
+    D: Deserializer<'de>,
+    T: std::str::FromStr + std::fmt::Debug,
+    T::Err: std::fmt::Display + std::fmt::Debug,
+{
+    let opt: Option<String> = Option::deserialize(de)?;
+    match opt.as_deref() {
+        None | Some("") => Ok(None),
+        Some(s) => std::str::FromStr::from_str(s)
+            .map_err(serde::de::Error::custom)
+            .map(Some),
+    }
+}
+
 #[derive(Deserialize)]
 #[serde(rename_all = "kebab-case")]
 struct FormData {
+    #[serde(default, deserialize_with = "deserialize_empty_string_as_none")]
     name: Option<String>,
     email: String,
+    #[serde(default, deserialize_with = "deserialize_empty_string_as_none")]
     company_name: Option<String>,
     service: String,
     help: String,
+    #[serde(default, deserialize_with = "deserialize_empty_string_as_none")]
     hear_about: Option<String>,
+    #[serde(default, deserialize_with = "deserialize_empty_string_as_none")]
     other_source: Option<String>,
 }
 
 struct State {
     username: String,
     password: String,
+    target_address: String,
 }
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let username = std::env::var("WEBMAIL_USERNAME")?;
     let password = std::env::var("WEBMAIL_PASSWORD")?;
+    let target_address = std::env::var("WEBMAIL_TARGET")?;
 
-    let state = State { username, password };
+    let state = State {
+        username,
+        password,
+        target_address,
+    };
 
     let app = Router::new()
         .route("/submit-email", post(handle_form))
@@ -105,10 +130,13 @@ async fn send_email(form_data: FormData, state: &State) -> Result<(), Box<dyn Er
     let email = Message::builder()
         .from(username.parse()?)
         .reply_to(email)
-        .to("ryan@distrust.co".parse()?)
-        .cc("anton@distrust.co".parse()?)
+        .to(state.target_address.parse()?)
         .subject("New Website Form Inquiry")
-        .body(body)?;
+        .singlepart(
+            SinglePart::builder()
+                .header(ContentType::TEXT_PLAIN)
+                .body(body),
+        )?;
 
     let credentials = lettre::transport::smtp::authentication::Credentials::new(
         username.clone(),