From d41a92d07a6eed48f5e22dfba9b911bb6a0f591f Mon Sep 17 00:00:00 2001
From: "Z. Charles Dziura" <zachary@dziura.email>
Date: Sat, 5 Oct 2024 08:09:46 -0400
Subject: [PATCH] Adding a service to handle caching

---
 api/.env                                      |  1 +
 api/Cargo.toml                                | 11 ++-
 api/src/db/mod.rs                             |  4 +-
 api/src/db/user.rs                            | 24 +++++-
 api/src/main.rs                               | 21 +++--
 api/src/models/api_response.rs                |  2 +-
 api/src/models/environment.rs                 | 78 ++++++++++++++-----
 api/src/models/error.rs                       | 56 +++++++++----
 api/src/models/mod.rs                         |  2 +
 api/src/models/session.rs                     | 32 ++++++++
 api/src/requests/auth/login/handler.rs        | 32 +++++++-
 api/src/requests/auth/login/mod.rs            |  1 +
 api/src/requests/auth/login/models/mod.rs     |  5 ++
 api/src/requests/auth/login/models/request.rs | 20 +++++
 .../requests/auth/login/models/response.rs    | 19 +++++
 api/src/requests/mod.rs                       | 32 +++++---
 api/src/requests/user/create/handler.rs       | 43 +++++++---
 api/src/requests/user/create/models/mod.rs    |  8 +-
 .../{registration_request.rs => request.rs}   |  0
 .../{registration_response.rs => response.rs} |  2 +-
 api/src/requests/user/verify/handler.rs       |  3 +-
 .../requests/user/verify/models/response.rs   |  4 +-
 api/src/services/auth_token.rs                | 32 ++++----
 api/src/services/cache.rs                     | 64 +++++++++++++++
 api/src/services/hasher.rs                    | 14 ----
 api/src/services/mod.rs                       |  8 +-
 api/src/services/password_hasher.rs           | 25 ++++++
 api/src/services/user_session.rs              | 38 +++++++++
 28 files changed, 466 insertions(+), 115 deletions(-)
 create mode 100644 api/src/models/session.rs
 create mode 100644 api/src/requests/auth/login/models/mod.rs
 create mode 100644 api/src/requests/auth/login/models/request.rs
 create mode 100644 api/src/requests/auth/login/models/response.rs
 rename api/src/requests/user/create/models/{registration_request.rs => request.rs} (100%)
 rename api/src/requests/user/create/models/{registration_response.rs => response.rs} (91%)
 create mode 100644 api/src/services/cache.rs
 delete mode 100644 api/src/services/hasher.rs
 create mode 100644 api/src/services/password_hasher.rs
 create mode 100644 api/src/services/user_session.rs

diff --git a/api/.env b/api/.env
index b0548e2..d86f937 100644
--- a/api/.env
+++ b/api/.env
@@ -1,4 +1,5 @@
 ASSETS_DIR=/home/zcdziura/Documents/Projects/debt-pirate/api/assets
+CACHE_URL=redis://debt_pirate:H553jOui2734@192.168.122.251:6379
 DATABASE_URL=postgres://debt_pirate:HRURqlUmtjIy@192.168.122.251/debt_pirate
 HOSTNAME=localhost
 MAINTENANCE_USER_ACCOUNT=debt_pirate:HRURqlUmtjIy
diff --git a/api/Cargo.toml b/api/Cargo.toml
index e1c3b75..52f2c3a 100644
--- a/api/Cargo.toml
+++ b/api/Cargo.toml
@@ -11,10 +11,12 @@ axum = { version = "0.7", features = [
 	"ws",
 ] }
 base64 = "0.22"
+bb8-redis = "0.17"
+blake3 = { version = "1.5", features = ["serde"] }
 dotenvy = "0.15"
 futures = "0.3"
 http = "1.0"
-humantime = "2.1.0"
+humantime = "2.1"
 humantime-serde = "1.1"
 hyper = { version = "1.1", features = ["full"] }
 lettre = { version = "0.11", default-features = false, features = [
@@ -27,6 +29,7 @@ lettre = { version = "0.11", default-features = false, features = [
 ] }
 num_cpus = "1.16"
 pasetors = "0.7"
+redis = { version = "0.27", features = ["aio"] }
 serde = { version = "1.0", features = ["derive", "rc", "std"] }
 serde_json = "1.0"
 serde_with = "3.9"
@@ -37,11 +40,11 @@ sqlx = { version = "0.8", features = [
 	"runtime-tokio",
 ] }
 syslog-tracing = "0.3.1"
-time = { version = "0.3.36", features = ["formatting", "macros"] }
+time = { version = "0.3", features = ["formatting", "macros"] }
 tokio = { version = "1.35", features = ["full"] }
 tower = "0.5"
 tower-http = { version = "0.6", features = ["full"] }
 tracing = "0.1.40"
-tracing-subscriber = { version = "0.3.18", features = ["env-filter", "time"] }
-ulid = "1.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter", "time"] }
+url = { version = "2.5.2", features = ["expose_internals"] }
 uuid = { version = "1.10", features = ["serde", "v7"] }
diff --git a/api/src/db/mod.rs b/api/src/db/mod.rs
index 6903f20..c03d04d 100644
--- a/api/src/db/mod.rs
+++ b/api/src/db/mod.rs
@@ -7,12 +7,12 @@ use crate::models::AppError;
 
 pub type DbPool = Pool<Postgres>;
 
-pub async fn create_connection_pool(connection_uri: &str) -> DbPool {
+pub async fn create_db_connection_pool(connection_uri: String) -> DbPool {
     let num_cpus = num_cpus::get() as u32;
 
     PgPoolOptions::new()
         .max_connections(num_cpus)
-        .connect(connection_uri)
+        .connect(connection_uri.as_str())
         .await
         .unwrap()
 }
diff --git a/api/src/db/user.rs b/api/src/db/user.rs
index fc4f13d..e71b62c 100644
--- a/api/src/db/user.rs
+++ b/api/src/db/user.rs
@@ -59,13 +59,35 @@ pub async fn insert_new_user(
 		})
 }
 
+#[derive(Debug, FromRow)]
+pub struct UserIdAndHashedPassword {
+    pub id: i32,
+    pub password: String,
+}
+
+pub async fn get_username_and_password_by_username(
+    pool: &DbPool,
+    username: String,
+) -> Result<UserIdAndHashedPassword, AppError> {
+    sqlx::query_as::<_, UserIdAndHashedPassword>(
+        "SELECT id, password FROM public.user WHERE username = $1;",
+    )
+    .bind(username)
+    .fetch_one(pool)
+    .await
+    .map_err(|err| {
+        error!(%err, "Unable to find user");
+        AppError::from(err)
+    })
+}
+
 pub async fn verify_user(pool: &DbPool, user_id: i32) -> Result<(), AppError> {
     sqlx::query("UPDATE public.user SET status_id = 1, updated_at = now() WHERE id = $1;")
         .bind(user_id)
         .execute(pool)
         .await
         .map_err(|err| {
-            eprintln!("Error verifying user with id '{user_id}'.");
+            error!(%err, user_id, "Error verifying user");
             AppError::from(err)
         })
         .map(|_| ())
diff --git a/api/src/main.rs b/api/src/main.rs
index 8e483bd..295fcd8 100644
--- a/api/src/main.rs
+++ b/api/src/main.rs
@@ -7,11 +7,13 @@ mod models;
 mod requests;
 mod services;
 
-use db::{create_connection_pool, run_migrations};
+use db::{create_db_connection_pool, run_migrations};
 use requests::start_app;
-use services::{initialize_logger, start_emailer_service, UserConfirmationMessage};
+use services::{
+    create_cache_connection_pool, initialize_logger, start_emailer_service, UserConfirmationMessage,
+};
 use tokio::runtime::Handle;
-use tracing::info;
+use tracing::{error, info};
 
 #[tokio::main]
 async fn main() {
@@ -28,11 +30,18 @@ async fn main() {
     initialize_logger(&env);
 
     info!("Initializing database connection pool...");
-    let pool = create_connection_pool(env.db_connection_uri()).await;
+    let db_pool = create_db_connection_pool(env.db_connection_uri().to_string()).await;
     info!("Database connection pool created successfully.");
 
+    info!("Initializing cache service connection pool...");
+    let cache_pool = create_cache_connection_pool(env.cache_url().to_string())
+        .await
+        .inspect_err(|err| error!(?err))
+        .unwrap();
+    info!("Cache service connection pool created successfully.");
+
     info!("Running database schema migrations...");
-    if let Err(err) = run_migrations(&pool).await {
+    if let Err(err) = run_migrations(&db_pool).await {
         eprintln!("{err:?}");
         process::exit(2);
     }
@@ -42,7 +51,7 @@ async fn main() {
     start_emailer_service(Handle::current(), env.assets_dir(), rx);
     info!("Email service started successfully.");
 
-    if let Err(err) = start_app(pool, env).await {
+    if let Err(err) = start_app(db_pool, cache_pool, env).await {
         eprintln!("{err:?}");
         process::exit(3);
     }
diff --git a/api/src/models/api_response.rs b/api/src/models/api_response.rs
index 9fb0c73..d2c6493 100644
--- a/api/src/models/api_response.rs
+++ b/api/src/models/api_response.rs
@@ -50,7 +50,7 @@ impl ApiResponse<()> {
         }
     }
 
-    pub fn error(error: &'static str) -> Self {
+    pub fn _error(error: &'static str) -> Self {
         Self {
             meta: None,
             data: None,
diff --git a/api/src/models/environment.rs b/api/src/models/environment.rs
index b33cd1d..e79d7a8 100644
--- a/api/src/models/environment.rs
+++ b/api/src/models/environment.rs
@@ -4,6 +4,8 @@ use std::{
 };
 
 use pasetors::{keys::SymmetricKey, version4::V4};
+use tracing::trace;
+use url::Url;
 
 use crate::services::UserConfirmationMessage;
 
@@ -12,7 +14,8 @@ use super::AppError;
 #[derive(Clone)]
 pub struct Environment {
     assets_dir: PathBuf,
-    database_url: String,
+    cache_url: Url,
+    database_url: Url,
     email_sender: Sender<UserConfirmationMessage>,
     hostname: String,
     port: u32,
@@ -29,6 +32,7 @@ impl Environment {
             .filter_map(|item| item.ok())
             .for_each(|(key, value)| match key.as_str() {
                 "ASSETS_DIR" => builder.with_assets_dir(value),
+                "CACHE_URL" => builder.with_cache_url(value),
                 "DATABASE_URL" => builder.with_database_url(value),
                 "HOSTNAME" => builder.with_hostname(value),
                 "PORT" => builder.with_port(value),
@@ -46,6 +50,22 @@ impl Environment {
         }
     }
 
+    pub fn assets_dir(&self) -> &Path {
+        self.assets_dir.as_path()
+    }
+
+    pub fn cache_url(&self) -> &Url {
+        &self.cache_url
+    }
+
+    pub fn db_connection_uri(&self) -> &Url {
+        &self.database_url
+    }
+
+    pub fn email_sender(&self) -> &Sender<UserConfirmationMessage> {
+        &self.email_sender
+    }
+
     pub fn hostname(&self) -> &str {
         self.hostname.as_str()
     }
@@ -54,22 +74,6 @@ impl Environment {
         self.port
     }
 
-    pub fn token_key(&self) -> &SymmetricKey<V4> {
-        &self.token_key
-    }
-
-    pub fn db_connection_uri(&self) -> &str {
-        self.database_url.as_str()
-    }
-
-    pub fn assets_dir(&self) -> &Path {
-        self.assets_dir.as_path()
-    }
-
-    pub fn email_sender(&self) -> &Sender<UserConfirmationMessage> {
-        &self.email_sender
-    }
-
     pub fn rust_log(&self) -> &str {
         self.rust_log.as_str()
     }
@@ -77,12 +81,17 @@ impl Environment {
     pub fn send_verification_email(&self) -> bool {
         self.send_verification_email
     }
+
+    pub fn token_key(&self) -> &SymmetricKey<V4> {
+        &self.token_key
+    }
 }
 
 impl From<EnvironmentObjectBuilder> for Environment {
     fn from(builder: EnvironmentObjectBuilder) -> Self {
         let EnvironmentObjectBuilder {
             assets_dir,
+            cache_url,
             database_url,
             email_sender,
             hostname,
@@ -94,6 +103,7 @@ impl From<EnvironmentObjectBuilder> for Environment {
 
         Self {
             assets_dir: assets_dir.unwrap(),
+            cache_url: cache_url.unwrap(),
             database_url: database_url.unwrap(),
             email_sender: email_sender.unwrap(),
             hostname: hostname.unwrap(),
@@ -108,7 +118,8 @@ impl From<EnvironmentObjectBuilder> for Environment {
 #[derive(Debug, Default)]
 pub struct EnvironmentObjectBuilder {
     pub assets_dir: Option<PathBuf>,
-    pub database_url: Option<String>,
+    pub cache_url: Option<Url>,
+    pub database_url: Option<Url>,
     pub email_sender: Option<Sender<UserConfirmationMessage>>,
     pub hostname: Option<String>,
     pub port: Option<u32>,
@@ -128,13 +139,20 @@ impl EnvironmentObjectBuilder {
     pub fn uninitialized_variables(&self) -> Option<Vec<&'static str>> {
         let mut missing_vars = [
             ("HOSTNAME", self.hostname.as_deref()),
-            ("DATABASE_URL", self.database_url.as_deref()),
             ("RUST_LOG", self.rust_log.as_deref()),
         ]
         .into_iter()
         .filter_map(|(key, value)| value.map(|_| key).xor(Some(key)))
         .collect::<Vec<&'static str>>();
 
+        if self.cache_url.is_none() {
+            missing_vars.push("CACHE_URL");
+        }
+
+        if self.database_url.is_none() {
+            missing_vars.push("DATABASE_URL");
+        }
+
         if self.token_key.is_none() {
             missing_vars.push("TOKEN_KEY");
         }
@@ -170,8 +188,28 @@ impl EnvironmentObjectBuilder {
         };
     }
 
+    pub fn with_cache_url(&mut self, url: String) {
+        trace!(?url);
+
+        let cache_url = url
+            .parse::<Url>()
+            .expect("The 'CACHE_URL' variable is not in valid URI format");
+
+        trace!(?cache_url);
+
+        if cache_url.scheme().to_lowercase() != "redis" {
+            panic!("The 'CACHE_URL' must be a valid Redis connection string; it must use the 'redis://' scheme");
+        }
+
+        self.cache_url = Some(cache_url);
+    }
+
     pub fn with_database_url(&mut self, url: String) {
-        self.database_url = Some(url);
+        let database_url = url
+            .parse::<Url>()
+            .expect("The 'DATABASE_URL' variable is not in valid URI format");
+
+        self.database_url = Some(database_url);
     }
 
     pub fn with_assets_dir(&mut self, assets_dir_path: String) {
diff --git a/api/src/models/error.rs b/api/src/models/error.rs
index 2df809d..6002ae1 100644
--- a/api/src/models/error.rs
+++ b/api/src/models/error.rs
@@ -1,8 +1,11 @@
 use std::{borrow::Cow, error::Error, fmt::Display, io};
 
 use axum::response::IntoResponse;
+use bb8_redis::bb8::RunError;
 use http::StatusCode;
+use redis::RedisError;
 use sqlx::{error::DatabaseError, migrate::MigrateError, Error as SqlxError};
+use tracing::trace;
 
 use super::ApiResponse;
 
@@ -11,6 +14,8 @@ pub struct AppError {
     kind: ErrorKind,
 }
 
+impl Error for AppError {}
+
 impl AppError {
     fn new(kind: ErrorKind) -> Self {
         Self { kind }
@@ -20,17 +25,20 @@ impl AppError {
         Self::new(ErrorKind::AppStartupError(error))
     }
 
+    pub fn connection_info(service_name: &'static str) -> Self {
+        Self::new(ErrorKind::ConnectionInfo(service_name))
+    }
+
     pub fn duplicate_record(message: &str) -> Self {
         Self::new(ErrorKind::DuplicateRecord(message.to_owned()))
     }
 
-    pub fn invalid_token() -> Self {
-        Self::new(ErrorKind::InvalidToken)
+    pub fn invalid_password() -> Self {
+        Self::new(ErrorKind::InvalidPassword)
     }
 
-    #[allow(dead_code)]
-    pub fn invalid_token_audience(audience: &str) -> Self {
-        Self::new(ErrorKind::InvalidTokenAudience(audience.to_owned()))
+    pub fn invalid_token() -> Self {
+        Self::new(ErrorKind::InvalidToken)
     }
 
     pub fn missing_environment_variables(missing_vars: Vec<&'static str>) -> Self {
@@ -74,11 +82,30 @@ impl From<SqlxError> for AppError {
     }
 }
 
+impl From<RedisError> for AppError {
+    fn from(other: RedisError) -> Self {
+        trace!(err = ?other, "Cache error");
+        Self::new(ErrorKind::Cache(other.to_string()))
+    }
+}
+
+impl From<RunError<RedisError>> for AppError {
+    fn from(other: RunError<RedisError>) -> Self {
+        trace!(err = ?other, "Cache pool error");
+        Self::new(ErrorKind::Cache(other.to_string()))
+    }
+}
+
 impl Display for AppError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match &self.kind {
             ErrorKind::AppStartupError(err) => write!(f, "{err}"),
-            ErrorKind::Database => write!(f, "Unknown database error occurred."),
+            ErrorKind::Cache(err) => write!(f, "{err}"),
+            ErrorKind::ConnectionInfo(service) => write!(
+                f,
+                "Unable to connect to '{service}' service; invalid connection string"
+            ),
+            ErrorKind::Database => write!(f, "Unknown database error occurred"),
             ErrorKind::DbMigration(err) => write!(
                 f,
                 "Error occurred while initializing connection to database: {err}"
@@ -86,11 +113,8 @@ impl Display for AppError {
             ErrorKind::DuplicateRecord(message) => {
                 write!(f, "Duplicate database record: {message}")
             }
-            ErrorKind::InvalidToken => write!(f, "The provided token is invalid."),
-            ErrorKind::InvalidTokenAudience(audience) => write!(
-                f,
-                "The provided token is not valid for this endpoint: '{audience}'."
-            ),
+            ErrorKind::InvalidPassword => write!(f, "Invalid password"),
+            ErrorKind::InvalidToken => write!(f, "The provided token is invalid"),
             ErrorKind::MissingEnvironmentVariables(missing_vars) => write!(
                 f,
                 "Missing required environment variables: {}",
@@ -99,22 +123,22 @@ impl Display for AppError {
             ErrorKind::Sqlx(err) => write!(f, "{err}"),
             ErrorKind::TokenKey => write!(
                 f,
-                "Invalid PASETO symmetric key; must be in valid PASERK format."
+                "Invalid PASETO symmetric key; must be in valid PASERK format"
             ),
         }
     }
 }
 
-impl Error for AppError {}
-
 #[derive(Debug)]
 enum ErrorKind {
     AppStartupError(io::Error),
+    Cache(String),
+    ConnectionInfo(&'static str),
     Database,
     DbMigration(MigrateError),
     DuplicateRecord(String),
+    InvalidPassword,
     InvalidToken,
-    InvalidTokenAudience(String),
     MissingEnvironmentVariables(Vec<&'static str>),
     Sqlx(SqlxError),
     TokenKey,
@@ -127,7 +151,7 @@ impl IntoResponse for AppError {
                 StatusCode::CONFLICT,
                 ApiResponse::new_with_error(self).into_json_response(),
             ),
-            &ErrorKind::InvalidToken | &ErrorKind::InvalidTokenAudience(_) => (
+            &ErrorKind::InvalidPassword | &ErrorKind::InvalidToken => (
                 StatusCode::BAD_REQUEST,
                 ApiResponse::new_with_error(self).into_json_response(),
             ),
diff --git a/api/src/models/mod.rs b/api/src/models/mod.rs
index 7446c05..df1ca68 100644
--- a/api/src/models/mod.rs
+++ b/api/src/models/mod.rs
@@ -1,7 +1,9 @@
 mod api_response;
 mod environment;
 mod error;
+mod session;
 
 pub use api_response::*;
 pub use environment::*;
 pub use error::*;
+pub use session::*;
diff --git a/api/src/models/session.rs b/api/src/models/session.rs
new file mode 100644
index 0000000..db171c5
--- /dev/null
+++ b/api/src/models/session.rs
@@ -0,0 +1,32 @@
+use std::time::SystemTime;
+
+use humantime::format_rfc3339;
+use redis::ToRedisArgs;
+
+#[derive(Debug)]
+pub struct Session {
+    pub user_id: i32,
+    pub username: String,
+    pub created_at: SystemTime,
+    pub expires_at: SystemTime,
+}
+
+impl Session {
+    pub fn to_cacheable_object<'a>(
+        self,
+    ) -> Vec<(&'static str, impl ToRedisArgs + Send + Sync + 'a)> {
+        let Self {
+            user_id,
+            username,
+            created_at,
+            expires_at,
+        } = self;
+
+        vec![
+            ("userId", user_id.to_string()),
+            ("username", username),
+            ("createdAt", format_rfc3339(created_at).to_string()),
+            ("expiresAt", format_rfc3339(expires_at).to_string()),
+        ]
+    }
+}
diff --git a/api/src/requests/auth/login/handler.rs b/api/src/requests/auth/login/handler.rs
index f842d9b..08f0aea 100644
--- a/api/src/requests/auth/login/handler.rs
+++ b/api/src/requests/auth/login/handler.rs
@@ -1,11 +1,39 @@
 use axum::{
     debug_handler,
+    extract::State,
     response::{IntoResponse, Response},
+    Json,
+};
+use tracing::debug;
+
+use crate::{
+    db::{get_username_and_password_by_username, DbPool, UserIdAndHashedPassword},
+    models::AppError,
+    requests::AppState,
+    services::verify_password,
 };
 
-use crate::models::AppError;
+use super::models::AuthLoginRequest;
 
 #[debug_handler]
-pub async fn auth_login_post_handler() -> Result<Response, AppError> {
+pub async fn auth_login_post_handler(
+    State(state): State<AppState>,
+    Json(body): Json<AuthLoginRequest>,
+) -> Result<Response, AppError> {
+    let pool = state.db_pool();
+    auth_login_request(pool, body).await
+}
+
+async fn auth_login_request(pool: &DbPool, body: AuthLoginRequest) -> Result<Response, AppError> {
+    debug!(?body);
+
+    let AuthLoginRequest { username, password } = body;
+    let UserIdAndHashedPassword {
+        id: _id,
+        password: hashed_password,
+    } = get_username_and_password_by_username(pool, username).await?;
+
+    verify_password(password, hashed_password)?;
+
     Ok(().into_response())
 }
diff --git a/api/src/requests/auth/login/mod.rs b/api/src/requests/auth/login/mod.rs
index 7298495..f00e7ca 100644
--- a/api/src/requests/auth/login/mod.rs
+++ b/api/src/requests/auth/login/mod.rs
@@ -1,3 +1,4 @@
 mod handler;
+mod models;
 
 pub use handler::*;
diff --git a/api/src/requests/auth/login/models/mod.rs b/api/src/requests/auth/login/models/mod.rs
new file mode 100644
index 0000000..b8be632
--- /dev/null
+++ b/api/src/requests/auth/login/models/mod.rs
@@ -0,0 +1,5 @@
+mod request;
+mod response;
+
+pub use request::*;
+pub use response::*;
diff --git a/api/src/requests/auth/login/models/request.rs b/api/src/requests/auth/login/models/request.rs
new file mode 100644
index 0000000..1ea4768
--- /dev/null
+++ b/api/src/requests/auth/login/models/request.rs
@@ -0,0 +1,20 @@
+use std::fmt::Debug;
+
+use serde::Deserialize;
+use serde_with::serde_as;
+
+#[serde_as]
+#[derive(Deserialize)]
+pub struct AuthLoginRequest {
+    pub username: String,
+    pub password: String,
+}
+
+impl Debug for AuthLoginRequest {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("AuthLoginRequest")
+            .field("username", &self.username)
+            .field("password", &"********")
+            .finish()
+    }
+}
diff --git a/api/src/requests/auth/login/models/response.rs b/api/src/requests/auth/login/models/response.rs
new file mode 100644
index 0000000..64693db
--- /dev/null
+++ b/api/src/requests/auth/login/models/response.rs
@@ -0,0 +1,19 @@
+use std::time::SystemTime;
+
+use serde::Serialize;
+
+#[derive(Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct AuthLoginResponse {
+    pub user_id: i32,
+    pub access: AuthLoginTokenData,
+    pub auth: AuthLoginTokenData,
+}
+
+#[derive(Debug, Serialize)]
+pub struct AuthLoginTokenData {
+    pub token: String,
+
+    #[serde(serialize_with = "humantime_serde::serialize")]
+    pub expiration: SystemTime,
+}
diff --git a/api/src/requests/mod.rs b/api/src/requests/mod.rs
index c20fa62..02402d3 100644
--- a/api/src/requests/mod.rs
+++ b/api/src/requests/mod.rs
@@ -12,26 +12,36 @@ use humantime::format_duration;
 use tokio::net::TcpListener;
 use tower_http::trace::TraceLayer;
 use tracing::{error, info, info_span, warn, Span};
-use ulid::Ulid;
+use uuid::Uuid;
 
 use crate::{
     db::DbPool,
     models::{AppError, Environment},
+    services::CachePool,
 };
 
 #[derive(Clone)]
 pub struct AppState {
-    pool: DbPool,
+    db_pool: DbPool,
+    cache_pool: CachePool,
     env: Environment,
 }
 
 impl AppState {
-    pub fn new(pool: DbPool, env: Environment) -> Self {
-        Self { pool, env }
+    pub fn new(db_pool: DbPool, cache_pool: CachePool, env: Environment) -> Self {
+        Self {
+            db_pool,
+            cache_pool,
+            env,
+        }
     }
 
-    pub fn pool(&self) -> &DbPool {
-        &self.pool
+    pub fn db_pool(&self) -> &DbPool {
+        &self.db_pool
+    }
+
+    pub fn cache_pool(&self) -> &CachePool {
+        &self.cache_pool
     }
 
     pub fn env(&self) -> &Environment {
@@ -39,7 +49,11 @@ impl AppState {
     }
 }
 
-pub async fn start_app(pool: DbPool, env: Environment) -> Result<(), AppError> {
+pub async fn start_app(
+    db_pool: DbPool,
+    cache_pool: CachePool,
+    env: Environment,
+) -> Result<(), AppError> {
     let address = env.hostname();
     let port = env.port();
 
@@ -55,7 +69,7 @@ pub async fn start_app(pool: DbPool, env: Environment) -> Result<(), AppError> {
 				.get::<MatchedPath>()
 				.map(MatchedPath::as_str).unwrap_or(request.uri().path());
 
-			info_span!("api_request", request_id = %Ulid::new(), method = %request.method(), %path, status = tracing::field::Empty)
+			info_span!("api_request", request_id = %Uuid::now_v7(), method = %request.method(), %path, status = tracing::field::Empty)
 		})
 		.on_response(|response: &Response, duration: Duration, span: &Span| {
 			let status = response.status();
@@ -68,7 +82,7 @@ pub async fn start_app(pool: DbPool, env: Environment) -> Result<(), AppError> {
 			}
 		});
 
-    let state = AppState::new(pool, env);
+    let state = AppState::new(db_pool, cache_pool, env);
     let app = Router::new()
         .merge(user::requests(state.clone()))
         .merge(auth::requests(state.clone()))
diff --git a/api/src/requests/user/create/handler.rs b/api/src/requests/user/create/handler.rs
index c19e854..72fa5dd 100644
--- a/api/src/requests/user/create/handler.rs
+++ b/api/src/requests/user/create/handler.rs
@@ -1,10 +1,13 @@
-use std::sync::mpsc::Sender;
+use std::{sync::mpsc::Sender, time::SystemTime};
 
 use crate::{
     db::{insert_new_user, DbPool, NewUserEntity, UserEntity},
-    models::{ApiResponse, AppError},
+    models::{ApiResponse, AppError, Session},
     requests::AppState,
-    services::{auth_token::generate_new_user_token, hash_string, UserConfirmationMessage},
+    services::{
+        self, auth_token::generate_new_user_token, hash_password, CachePool,
+        UserConfirmationMessage,
+    },
 };
 use axum::{
     debug_handler,
@@ -27,7 +30,8 @@ pub async fn user_registration_post_handler(
 
     register_new_user_request(
         request,
-        state.pool(),
+        state.db_pool(),
+        state.cache_pool(),
         env.token_key(),
         env.send_verification_email(),
         env.email_sender(),
@@ -37,7 +41,8 @@ pub async fn user_registration_post_handler(
 
 async fn register_new_user_request(
     body: UserRegistrationRequest,
-    pool: &DbPool,
+    db_pool: &DbPool,
+    cache_pool: &CachePool,
     signing_key: &SymmetricKey<V4>,
     send_verification_email: bool,
     email_sender: &Sender<UserConfirmationMessage>,
@@ -51,10 +56,10 @@ async fn register_new_user_request(
         name,
     } = body;
 
-    let hashed_password = hash_string(password);
+    let hashed_password = hash_password(password);
 
     let new_user = NewUserEntity {
-        username,
+        username: username.clone(),
         password: hashed_password.to_string(),
         email,
         name,
@@ -65,7 +70,7 @@ async fn register_new_user_request(
         name,
         email,
         ..
-    } = insert_new_user(pool, new_user).await.map_err(|err| {
+    } = insert_new_user(db_pool, new_user).await.map_err(|err| {
         if err.is_duplicate_record() {
             AppError::duplicate_record(
                 "There is already an account associated with this username or email address.",
@@ -75,7 +80,23 @@ async fn register_new_user_request(
         }
     })?;
 
-    let (verification_token, expiration) = generate_new_user_token(signing_key, user_id);
+    let (verification_token, token_id, expires_at) = generate_new_user_token(signing_key, user_id);
+
+    let new_user_session = Session {
+        user_id,
+        username,
+        created_at: SystemTime::now(),
+        expires_at,
+    };
+
+    let expires_in = expires_at.duration_since(SystemTime::now()).unwrap();
+    services::user_session::store_user_session(
+        cache_pool,
+        token_id,
+        new_user_session,
+        Some(expires_in),
+    )
+    .await?;
 
     let response_body = if send_verification_email {
         let new_user_confirmation_message = UserConfirmationMessage {
@@ -92,13 +113,13 @@ async fn register_new_user_request(
 
         UserRegistrationResponse {
             id: user_id,
-            expiration,
+            expires_at,
             verification_token: None,
         }
     } else {
         UserRegistrationResponse {
             id: user_id,
-            expiration,
+            expires_at,
             verification_token: Some(verification_token),
         }
     };
diff --git a/api/src/requests/user/create/models/mod.rs b/api/src/requests/user/create/models/mod.rs
index d30e4ef..b8be632 100644
--- a/api/src/requests/user/create/models/mod.rs
+++ b/api/src/requests/user/create/models/mod.rs
@@ -1,5 +1,5 @@
-mod registration_request;
-mod registration_response;
+mod request;
+mod response;
 
-pub use registration_request::*;
-pub use registration_response::*;
+pub use request::*;
+pub use response::*;
diff --git a/api/src/requests/user/create/models/registration_request.rs b/api/src/requests/user/create/models/request.rs
similarity index 100%
rename from api/src/requests/user/create/models/registration_request.rs
rename to api/src/requests/user/create/models/request.rs
diff --git a/api/src/requests/user/create/models/registration_response.rs b/api/src/requests/user/create/models/response.rs
similarity index 91%
rename from api/src/requests/user/create/models/registration_response.rs
rename to api/src/requests/user/create/models/response.rs
index dca7bc4..50b1338 100644
--- a/api/src/requests/user/create/models/registration_response.rs
+++ b/api/src/requests/user/create/models/response.rs
@@ -11,7 +11,7 @@ pub struct UserRegistrationResponse {
     pub id: i32,
 
     #[serde(serialize_with = "humantime_serde::serialize")]
-    pub expiration: SystemTime,
+    pub expires_at: SystemTime,
 
     pub verification_token: Option<String>,
 }
diff --git a/api/src/requests/user/verify/handler.rs b/api/src/requests/user/verify/handler.rs
index 81c49cc..b7faa92 100644
--- a/api/src/requests/user/verify/handler.rs
+++ b/api/src/requests/user/verify/handler.rs
@@ -23,7 +23,7 @@ pub async fn user_verification_get_handler(
     Path(user_id): Path<i32>,
     Query(query): Query<UserVerifyGetParams>,
 ) -> Result<Response, AppError> {
-    let pool = state.pool();
+    let pool = state.db_pool();
     let env = state.env();
 
     let UserVerifyGetParams { verification_token } = query;
@@ -42,7 +42,6 @@ async fn verify_new_user_request(
     let validation_rules = {
         let mut rules = ClaimsValidationRules::new();
         rules.validate_audience_with(format!("/user/{user_id}/verify").as_str());
-
         rules
     };
 
diff --git a/api/src/requests/user/verify/models/response.rs b/api/src/requests/user/verify/models/response.rs
index 98f7e1c..ada9805 100644
--- a/api/src/requests/user/verify/models/response.rs
+++ b/api/src/requests/user/verify/models/response.rs
@@ -12,8 +12,8 @@ pub struct UserVerifyGetResponse {
 
 impl UserVerifyGetResponse {
     pub fn new(key: &SymmetricKey<V4>, user_id: i32) -> Self {
-        let (access_token, access_token_expiration) = generate_access_token(key, user_id);
-        let (auth_token, auth_token_expiration) = generate_auth_token(key, user_id);
+        let (access_token, _, access_token_expiration) = generate_access_token(key, user_id);
+        let (auth_token, _, auth_token_expiration) = generate_auth_token(key, user_id);
 
         Self {
             access: UserVerifyGetResponseTokenAndExpiration {
diff --git a/api/src/services/auth_token.rs b/api/src/services/auth_token.rs
index 939cbc3..bc0656c 100644
--- a/api/src/services/auth_token.rs
+++ b/api/src/services/auth_token.rs
@@ -13,7 +13,7 @@ use uuid::Uuid;
 
 use crate::models::AppError;
 
-static FOURTY_FIVE_DAYS: Duration = Duration::from_secs(3_888_000);
+static ONE_DAY: Duration = Duration::from_secs(86_400);
 static ONE_HOUR: Duration = Duration::from_secs(3_600);
 static FIFTEEN_MINUTES: Duration = Duration::from_secs(900);
 
@@ -51,19 +51,19 @@ pub fn verify_token(
     Ok(())
 }
 
-pub fn generate_access_token(key: &SymmetricKey<V4>, user_id: i32) -> (String, SystemTime) {
-    generate_token(key, user_id, Some(FOURTY_FIVE_DAYS), None)
+pub fn generate_access_token(key: &SymmetricKey<V4>, user_id: i32) -> (String, Uuid, SystemTime) {
+    generate_token(key, user_id, ONE_HOUR, None)
 }
 
-pub fn generate_auth_token(key: &SymmetricKey<V4>, user_id: i32) -> (String, SystemTime) {
-    generate_token(key, user_id, None, None)
+pub fn generate_auth_token(key: &SymmetricKey<V4>, user_id: i32) -> (String, Uuid, SystemTime) {
+    generate_token(key, user_id, ONE_DAY, None)
 }
 
-pub fn generate_new_user_token(key: &SymmetricKey<V4>, user_id: i32) -> (String, SystemTime) {
+pub fn generate_new_user_token(key: &SymmetricKey<V4>, user_id: i32) -> (String, Uuid, SystemTime) {
     generate_token(
         key,
         user_id,
-        Some(FIFTEEN_MINUTES),
+        FIFTEEN_MINUTES,
         Some(format!("/user/{user_id}/verify").as_str()),
     )
 }
@@ -71,20 +71,16 @@ pub fn generate_new_user_token(key: &SymmetricKey<V4>, user_id: i32) -> (String,
 fn generate_token(
     key: &SymmetricKey<V4>,
     user_id: i32,
-    duration: Option<Duration>,
+    expires_in: Duration,
     audience: Option<&str>,
-) -> (String, SystemTime) {
+) -> (String, Uuid, SystemTime) {
     let now = SystemTime::now();
-    let expiration = if let Some(duration) = duration {
-        duration
-    } else {
-        ONE_HOUR
-    };
+    let token_id = Uuid::now_v7();
 
-    let token = Claims::new_expires_in(&expiration)
+    let token = Claims::new_expires_in(&expires_in)
         .and_then(|mut claims| {
             claims
-                .token_identifier(Uuid::now_v7().to_string().as_str())
+                .token_identifier(token_id.to_string().as_str())
                 .map(|_| claims)
         })
         .and_then(|mut claims| {
@@ -116,7 +112,7 @@ fn generate_token(
         })
         .unwrap();
 
-    (token, now + expiration)
+    (token, token_id, now + expires_in)
 }
 
 #[cfg(test)]
@@ -136,7 +132,7 @@ mod tests {
             .and_then(|bytes| SymmetricKey::<V4>::from(bytes.as_slice()).map_err(|_| ()))
             .unwrap();
 
-        let token = generate_token(&key, 1, Some(Duration::from_secs(60)), Some("testing")).0;
+        let token = generate_token(&key, 1, Duration::from_secs(60), Some("testing")).0;
 
         let footer = {
             let mut footer = Footer::new();
diff --git a/api/src/services/cache.rs b/api/src/services/cache.rs
new file mode 100644
index 0000000..4d40f6f
--- /dev/null
+++ b/api/src/services/cache.rs
@@ -0,0 +1,64 @@
+use std::{fmt::Debug, time::Duration};
+
+use bb8_redis::{
+    bb8::{Pool, PooledConnection},
+    RedisConnectionManager,
+};
+use redis::{AsyncCommands, IntoConnectionInfo, ToRedisArgs};
+
+use crate::models::AppError;
+
+pub type CachePool = Pool<RedisConnectionManager>;
+
+pub async fn create_cache_connection_pool(
+    connection_info: impl IntoConnectionInfo + Clone + Debug,
+) -> Result<CachePool, AppError> {
+    let manager = RedisConnectionManager::new(connection_info)
+        .map_err(|_| AppError::connection_info("cache"))?;
+    let pool = Pool::builder().build(manager).await.unwrap();
+
+    Ok(pool)
+}
+
+pub async fn store_object<
+    'a,
+    F: ToRedisArgs + Send + Sync + 'a,
+    V: ToRedisArgs + Send + Sync + 'a,
+    O: AsRef<[(F, V)]>,
+>(
+    cache_pool: &CachePool,
+    key: &str,
+    object: O,
+) -> Result<(), AppError> {
+    let mut conn = get_connection_from_pool(cache_pool).await?;
+
+    let _: () = conn.hset_multiple(key, object.as_ref()).await?;
+    Ok(())
+}
+
+pub async fn store_object_with_expiration<
+    'a,
+    F: ToRedisArgs + Send + Sync + 'a,
+    V: ToRedisArgs + Send + Sync + 'a,
+    O: AsRef<[(F, V)]>,
+>(
+    cache_pool: &CachePool,
+    key: &str,
+    object: O,
+    expiration: Duration,
+) -> Result<(), AppError> {
+    let mut conn = get_connection_from_pool(cache_pool).await?;
+
+    let _: () = conn.hset_multiple(key, object.as_ref()).await?;
+    let _: () = conn
+        .expire(key, expiration.as_secs().try_into().unwrap())
+        .await?;
+
+    Ok(())
+}
+
+async fn get_connection_from_pool(
+    cache_pool: &CachePool,
+) -> Result<PooledConnection<'_, RedisConnectionManager>, AppError> {
+    cache_pool.get().await.map_err(From::from)
+}
diff --git a/api/src/services/hasher.rs b/api/src/services/hasher.rs
deleted file mode 100644
index a4a0f5f..0000000
--- a/api/src/services/hasher.rs
+++ /dev/null
@@ -1,14 +0,0 @@
-use argon2::{
-    password_hash::{rand_core::OsRng, PasswordHash, PasswordHashString, SaltString},
-    Argon2,
-};
-
-pub fn hash_string(string: String) -> PasswordHashString {
-    let algorithm = Argon2::default();
-    let salt = SaltString::generate(&mut OsRng);
-
-    let hashed_password =
-        PasswordHash::generate(algorithm, string.as_bytes(), salt.as_salt()).unwrap();
-
-    hashed_password.serialize()
-}
diff --git a/api/src/services/mod.rs b/api/src/services/mod.rs
index 90666d3..1b397a5 100644
--- a/api/src/services/mod.rs
+++ b/api/src/services/mod.rs
@@ -1,8 +1,12 @@
 pub mod auth_token;
-mod hasher;
+mod cache;
 mod logger;
 mod mailer;
+mod password_hasher;
+pub mod user_session;
 
-pub use hasher::*;
 pub use logger::*;
 pub use mailer::*;
+pub use password_hasher::*;
+
+pub use cache::{create_cache_connection_pool, CachePool};
diff --git a/api/src/services/password_hasher.rs b/api/src/services/password_hasher.rs
new file mode 100644
index 0000000..574204d
--- /dev/null
+++ b/api/src/services/password_hasher.rs
@@ -0,0 +1,25 @@
+use argon2::{
+    password_hash::{rand_core::OsRng, PasswordHash, PasswordHashString, SaltString},
+    Argon2, PasswordVerifier,
+};
+
+use crate::models::AppError;
+
+pub fn hash_password(password: String) -> PasswordHashString {
+    let algorithm = Argon2::default();
+    let salt = SaltString::generate(&mut OsRng);
+
+    let hashed_password =
+        PasswordHash::generate(algorithm, password.as_bytes(), salt.as_salt()).unwrap();
+
+    hashed_password.serialize()
+}
+
+pub fn verify_password(password: String, hashed_password: String) -> Result<(), AppError> {
+    let algorithm = Argon2::default();
+    let hash = PasswordHash::new(hashed_password.as_str()).unwrap();
+
+    algorithm
+        .verify_password(password.as_bytes(), &hash)
+        .map_err(|_| AppError::invalid_password())
+}
diff --git a/api/src/services/user_session.rs b/api/src/services/user_session.rs
new file mode 100644
index 0000000..9152de9
--- /dev/null
+++ b/api/src/services/user_session.rs
@@ -0,0 +1,38 @@
+use std::time::Duration;
+
+use uuid::Uuid;
+
+use crate::{
+    models::{AppError, Session},
+    services::cache::CachePool,
+};
+
+use super::cache;
+
+static USER_SESSION_CACHE_KEY_PREFIX: &'static str = "debt_pirate:session:";
+
+pub async fn store_user_session(
+    cache_pool: &CachePool,
+    token_id: Uuid,
+    session: Session,
+    expiration: Option<Duration>,
+) -> Result<(), AppError> {
+    let hashed_token = blake3::hash(token_id.as_bytes());
+    let key = format!("{USER_SESSION_CACHE_KEY_PREFIX}{hashed_token}");
+    let cacheable_object = session.to_cacheable_object();
+
+    match expiration {
+        Some(expiration) => {
+            cache::store_object_with_expiration(
+                cache_pool,
+                key.as_str(),
+                cacheable_object,
+                expiration,
+            )
+            .await?
+        }
+        None => cache::store_object(cache_pool, key.as_str(), cacheable_object).await?,
+    }
+
+    Ok(())
+}