Use TryInto.

Cargo.lock

@@ -701,6 +701,25 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "env_logger"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "44533bbbb3bb3c1fa17d9f2e4e38bbbaf8396ba82193c4cb1b6445d711445d36"
+dependencies = [
+ "log",
+ "regex",
+]
+
+[[package]]
+name = "fake"
+version = "2.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6479fa2c7e83ddf8be7d435421e093b072ca891b99a49bc84eba098f4044f818"
+dependencies = [
+ "rand",
+]
+
 [[package]]
 name = "flate2"
 version = "1.0.19"
@@ -1609,6 +1628,29 @@ version = "1.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
 
+[[package]]
+name = "quickcheck"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a44883e74aa97ad63db83c4bf8ca490f02b2fc02f92575e720c8551e843c945f"
+dependencies = [
+ "env_logger",
+ "log",
+ "rand",
+ "rand_core",
+]
+
+[[package]]
+name = "quickcheck_macros"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "608c156fd8e97febc07dc9c2e2c80bf74cfc6ef26893eae3daf8bc2bc94a4b7f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "quote"
 version = "1.0.7"
@@ -2921,7 +2963,10 @@ dependencies = [
  "chrono",
  "claim",
  "config",
+ "fake",
  "lazy_static",
+ "quickcheck",
+ "quickcheck_macros",
  "reqwest",
  "serde",
  "serde-aux",

Cargo.toml

@@ -30,8 +30,11 @@ tracing-actix-web = "0.2.0"
 serde-aux = "1.0.1"
 unicode-segmentation = "1.7.1"
 validator = "0.12.0"
+quickcheck_macros = "0.9.1"
 
 [dev-dependencies]
 reqwest = { version = "0.10.7", features = ["json"] }
 lazy_static = "1.4.0"
 claim = "0.4.0"
+quickcheck = "0.9.2"
+fake = "2.3.0"

src/domain/mod.rs

@@ -1,6 +1,7 @@
-mod subscriber_name;
-mod subscriber_email;
 mod new_subscriber;
+mod subscriber_email;
+mod subscriber_name;
 
-pub use subscriber_name::SubscriberName;
 pub use new_subscriber::NewSubscriber;
+pub use subscriber_email::SubscriberEmail;
+pub use subscriber_name::SubscriberName;

src/domain/new_subscriber.rs

@@ -1,6 +1,8 @@
 use crate::domain::subscriber_name::SubscriberName;
+use crate::domain::subscriber_email::SubscriberEmail;
 
 pub struct NewSubscriber {
-    pub email: String,
+    // We are not using `String` anymore!
+    pub email: SubscriberEmail,
     pub name: SubscriberName,
 }

src/domain/subscriber_email.rs

@@ -23,6 +23,8 @@ impl AsRef<str> for SubscriberEmail {
 mod tests {
     use super::SubscriberEmail;
     use claim::assert_err;
+    use fake::Fake;
+    use fake::faker::internet::en::SafeEmail;
 
     #[test]
     fn empty_string_is_rejected() {
@@ -41,4 +43,19 @@ mod tests {
         let email = "@domain.com".to_string();
         assert_err!(SubscriberEmail::parse(email));
     }
+
+    #[derive(Debug, Clone)]
+    struct ValidEmailFixture(pub String);
+
+    impl quickcheck::Arbitrary for ValidEmailFixture {
+        fn arbitrary<G: quickcheck::Gen>(g: &mut G) -> Self {
+            let email = SafeEmail().fake_with_rng(g);
+            Self(email)
+        }
+    }
+
+    #[quickcheck_macros::quickcheck]
+    fn valid_emails_are_parsed_successfully(valid_email: ValidEmailFixture) -> bool {
+        SubscriberEmail::parse(valid_email.0).is_ok()
+    }
 }

src/routes/subscriptions.rs

@@ -1,7 +1,8 @@
-use crate::domain::{NewSubscriber, SubscriberName};
+use crate::domain::{NewSubscriber, SubscriberEmail, SubscriberName};
 use actix_web::{web, HttpResponse};
 use chrono::Utc;
 use sqlx::PgPool;
+use std::convert::TryInto;
 use uuid::Uuid;
 
 #[derive(serde::Deserialize)]
@@ -10,6 +11,16 @@ pub struct FormData {
     name: String,
 }
 
+impl TryInto<NewSubscriber> for FormData {
+    type Error = String;
+
+    fn try_into(self) -> Result<NewSubscriber, Self::Error> {
+        let name = SubscriberName::parse(self.name)?;
+        let email = SubscriberEmail::parse(self.email)?;
+        Ok(NewSubscriber { email, name })
+    }
+}
+
 #[tracing::instrument(
     name = "Adding a new subscriber",
     skip(form, pool),
@@ -22,12 +33,10 @@ pub async fn subscribe(
     form: web::Form<FormData>,
     pool: web::Data<PgPool>,
 ) -> Result<HttpResponse, HttpResponse> {
-    let name =
-        SubscriberName::parse(form.0.name).map_err(|_| HttpResponse::BadRequest().finish())?;
-    let new_subscriber = NewSubscriber {
-        email: form.0.email,
-        name,
-    };
+    let new_subscriber = form
+        .0
+        .try_into()
+        .map_err(|_| HttpResponse::BadRequest().finish())?;
     insert_subscriber(&pool, &new_subscriber)
         .await
         .map_err(|_| HttpResponse::InternalServerError().finish())?;
@@ -48,7 +57,7 @@ pub async fn insert_subscriber(
     VALUES ($1, $2, $3, $4)
             "#,
         Uuid::new_v4(),
-        new_subscriber.email,
+        new_subscriber.email.as_ref(),
         new_subscriber.name.as_ref(),
         Utc::now()
     )