feat(cards): validate card security code and expiration (#874)

Co-authored-by: Sanchith Hegde <[email protected]>

crates/cards/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "cards"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[features]
+default = ["serde"]
+
+[dependencies]
+time = { version = "0.3.20" }
+error-stack = "0.3.1"
+serde = { version = "1", features = ["derive"], optional = true }
+
+# First Party crates
+masking = { version = "0.1.0", path = "../masking" }
+common_utils = { version = "0.1.0", path = "../common_utils" }
+
+[dev-dependencies]
+serde_json = "1.0.94"

crates/cards/src/lib.rs

@@ -0,0 +1,190 @@
+use std::ops::Deref;
+
+use common_utils::{date_time, errors};
+use error_stack::report;
+use masking::{PeekInterface, StrongSecret};
+use serde::{
+    de::{self},
+    Deserialize, Serialize,
+};
+use time::{util::days_in_year_month, Date, Duration, PrimitiveDateTime, Time};
+
+#[derive(Serialize)]
+pub struct CardSecurityCode(StrongSecret<u16>);
+
+impl TryFrom<u16> for CardSecurityCode {
+    type Error = error_stack::Report<errors::ValidationError>;
+    fn try_from(csc: u16) -> Result<Self, Self::Error> {
+        if (100..=9999).contains(&csc) {
+            Ok(Self(StrongSecret::new(csc)))
+        } else {
+            Err(report!(errors::ValidationError::InvalidValue {
+                message: "invalid card security code".to_string()
+            }))
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for CardSecurityCode {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let csc = u16::deserialize(deserializer)?;
+        csc.try_into().map_err(de::Error::custom)
+    }
+}
+
+#[derive(Serialize)]
+pub struct CardExpirationMonth(StrongSecret<u8>);
+
+impl CardExpirationMonth {
+    pub fn two_digits(&self) -> String {
+        format!("{:02}", self.peek())
+    }
+}
+
+impl TryFrom<u8> for CardExpirationMonth {
+    type Error = error_stack::Report<errors::ValidationError>;
+    fn try_from(month: u8) -> Result<Self, Self::Error> {
+        if (1..=12).contains(&month) {
+            Ok(Self(StrongSecret::new(month)))
+        } else {
+            Err(report!(errors::ValidationError::InvalidValue {
+                message: "invalid card expiration month".to_string()
+            }))
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for CardExpirationMonth {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let month = u8::deserialize(deserializer)?;
+        month.try_into().map_err(de::Error::custom)
+    }
+}
+
+#[derive(Serialize)]
+pub struct CardExpirationYear(StrongSecret<u16>);
+
+impl CardExpirationYear {
+    pub fn four_digits(&self) -> String {
+        self.peek().to_string()
+    }
+
+    pub fn two_digits(&self) -> String {
+        let year = self.peek() % 100;
+        year.to_string()
+    }
+}
+
+impl TryFrom<u16> for CardExpirationYear {
+    type Error = error_stack::Report<errors::ValidationError>;
+    fn try_from(year: u16) -> Result<Self, Self::Error> {
+        let curr_year = u16::try_from(date_time::now().year()).map_err(|_| {
+            report!(errors::ValidationError::InvalidValue {
+                message: "invalid year".to_string()
+            })
+        })?;
+
+        if year >= curr_year {
+            Ok(Self(StrongSecret::<u16>::new(year)))
+        } else {
+            Err(report!(errors::ValidationError::InvalidValue {
+                message: "invalid card expiration year".to_string()
+            }))
+        }
+    }
+}
+
+impl<'de> Deserialize<'de> for CardExpirationYear {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let year = u16::deserialize(deserializer)?;
+        year.try_into().map_err(de::Error::custom)
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct CardExpiration {
+    pub month: CardExpirationMonth,
+    pub year: CardExpirationYear,
+}
+
+impl CardExpiration {
+    pub fn is_expired(&self) -> Result<bool, error_stack::Report<errors::ValidationError>> {
+        let current_datetime_utc = date_time::now();
+
+        let expiration_month = (*self.month.peek()).try_into().map_err(|_| {
+            report!(errors::ValidationError::InvalidValue {
+                message: "invalid month".to_string()
+            })
+        })?;
+
+        let expiration_year = *self.year.peek();
+
+        let expiration_day = days_in_year_month(i32::from(expiration_year), expiration_month);
+
+        let expiration_date =
+            Date::from_calendar_date(i32::from(expiration_year), expiration_month, expiration_day)
+                .map_err(|_| {
+                    report!(errors::ValidationError::InvalidValue {
+                        message: "error while constructing calendar date".to_string()
+                    })
+                })?;
+
+        let expiration_time = Time::MIDNIGHT;
+
+        // actual expiry date specified on card w.r.t. local timezone
+        // max diff b/w utc and other timezones is 14 hours
+        let mut expiration_datetime_utc = PrimitiveDateTime::new(expiration_date, expiration_time);
+
+        // compensating time difference b/w local and utc timezone by adding a day
+        expiration_datetime_utc = expiration_datetime_utc.saturating_add(Duration::days(1));
+
+        Ok(current_datetime_utc > expiration_datetime_utc)
+    }
+
+    pub fn get_month(&self) -> &CardExpirationMonth {
+        &self.month
+    }
+
+    pub fn get_year(&self) -> &CardExpirationYear {
+        &self.year
+    }
+}
+
+impl TryFrom<(u8, u16)> for CardExpiration {
+    type Error = error_stack::Report<errors::ValidationError>;
+    fn try_from(items: (u8, u16)) -> errors::CustomResult<Self, errors::ValidationError> {
+        let month = CardExpirationMonth::try_from(items.0)?;
+        let year = CardExpirationYear::try_from(items.1)?;
+        Ok(Self { month, year })
+    }
+}
+
+impl Deref for CardSecurityCode {
+    type Target = StrongSecret<u16>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Deref for CardExpirationMonth {
+    type Target = StrongSecret<u8>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl Deref for CardExpirationYear {
+    type Target = StrongSecret<u16>;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}

crates/cards/tests/basic.rs

@@ -0,0 +1,101 @@
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+
+use cards::{CardExpiration, CardExpirationMonth, CardExpirationYear, CardSecurityCode};
+use common_utils::date_time;
+use masking::PeekInterface;
+
+#[test]
+fn test_card_security_code() {
+    // no panic
+    let valid_card_security_code = CardSecurityCode::try_from(1234).unwrap();
+
+    // will panic on unwrap
+    let invalid_card_security_code = CardSecurityCode::try_from(12);
+
+    assert_eq!(*valid_card_security_code.peek(), 1234);
+    assert!(invalid_card_security_code.is_err());
+
+    let serialized = serde_json::to_string(&valid_card_security_code).unwrap();
+    assert_eq!(serialized, "1234");
+
+    let derialized = serde_json::from_str::<CardSecurityCode>(&serialized).unwrap();
+    assert_eq!(*derialized.peek(), 1234);
+
+    let invalid_deserialization = serde_json::from_str::<CardSecurityCode>("12");
+    assert!(invalid_deserialization.is_err());
+}
+
+#[test]
+fn test_card_expiration_month() {
+    // no panic
+    let card_exp_month = CardExpirationMonth::try_from(12).unwrap();
+
+    // will panic on unwrap
+    let invalid_card_exp_month = CardExpirationMonth::try_from(13);
+
+    assert_eq!(*card_exp_month.peek(), 12);
+    assert!(invalid_card_exp_month.is_err());
+
+    let serialized = serde_json::to_string(&card_exp_month).unwrap();
+    assert_eq!(serialized, "12");
+
+    let derialized = serde_json::from_str::<CardExpirationMonth>(&serialized).unwrap();
+    assert_eq!(*derialized.peek(), 12);
+
+    let invalid_deserialization = serde_json::from_str::<CardExpirationMonth>("13");
+    assert!(invalid_deserialization.is_err());
+}
+
+#[test]
+fn test_card_expiration_year() {
+    let curr_date = date_time::now();
+    let curr_year = u16::try_from(curr_date.year()).expect("valid year");
+
+    // no panic
+    let card_exp_year = CardExpirationYear::try_from(curr_year).unwrap();
+
+    // will panic on unwrap
+    let invalid_card_exp_year = CardExpirationYear::try_from(curr_year - 1);
+
+    assert_eq!(*card_exp_year.peek(), curr_year);
+    assert!(invalid_card_exp_year.is_err());
+
+    let serialized = serde_json::to_string(&card_exp_year).unwrap();
+    assert_eq!(serialized, curr_year.to_string());
+
+    let derialized = serde_json::from_str::<CardExpirationYear>(&serialized).unwrap();
+    assert_eq!(*derialized.peek(), curr_year);
+
+    let invalid_deserialization = serde_json::from_str::<CardExpirationYear>("123");
+    assert!(invalid_deserialization.is_err());
+}
+
+#[test]
+fn test_card_expiration() {
+    let curr_date = date_time::now();
+    let curr_year = u16::try_from(curr_date.year()).expect("valid year");
+
+    // no panic
+    let card_exp = CardExpiration::try_from((3, curr_year + 1)).unwrap();
+
+    // will panic on unwrap
+    let invalid_card_exp = CardExpiration::try_from((13, curr_year + 1));
+
+    assert_eq!(*card_exp.get_month().peek(), 3);
+    assert_eq!(*card_exp.get_year().peek(), curr_year + 1);
+    assert!(card_exp.is_expired().unwrap());
+
+    assert!(invalid_card_exp.is_err());
+
+    let serialized = serde_json::to_string(&card_exp).unwrap();
+    let expected_string = format!(r#"{{"month":{},"year":{}}}"#, 3, curr_year + 1);
+    assert_eq!(serialized, expected_string);
+
+    let derialized = serde_json::from_str::<CardExpiration>(&serialized).unwrap();
+    assert_eq!(*derialized.get_month().peek(), 3);
+    assert_eq!(*derialized.get_year().peek(), curr_year + 1);
+
+    let invalid_serialized_string = r#"{"month":13,"year":123}"#;
+    let invalid_deserialization = serde_json::from_str::<CardExpiration>(invalid_serialized_string);
+    assert!(invalid_deserialization.is_err());
+}

crates/masking/src/serde.rs

@@ -23,6 +23,8 @@ pub trait SerializableSecret: Serialize {}
 // pub trait NonSerializableSecret: Serialize {}
 
 impl SerializableSecret for serde_json::Value {}
+impl SerializableSecret for u8 {}
+impl SerializableSecret for u16 {}
 
 impl<'de, T, I> Deserialize<'de> for Secret<T, I>
 where