Add framework for captchas

Cargo.toml

@@ -13,8 +13,10 @@ diesel_migrations = "1.4.0"
 dotenv = "0.15.0"
 env_logger = "0.8.1"
 jsonwebtoken = "7.2.0"
+lazy_static = "1.4.0"
 r2d2 = "0.8.9"
 rand = "0.7.3"
 serde = { version = "1.0.117", features = ["derive"] }
 serde_json = "1.0.59"
 sodiumoxide = "0.2.6"
+uuid = { version = "0.8", features = ["v4"] }

src/main.rs

@@ -6,7 +6,8 @@ extern crate diesel;
 #[macro_use]
 extern crate diesel_migrations;
 
-use actix_web::{App, HttpServer};
+use actix_web::{web, App, HttpServer};
+use anyhow::Result;
 
 mod database;
 mod error;
@@ -15,18 +16,22 @@ mod routes;
 use routes::*;
 
 #[actix_web::main]
-async fn main() -> std::io::Result<()> {
+async fn main() -> Result<()> {
     dotenv::dotenv().ok();
     env_logger::Builder::from_env(env_logger::Env::default().default_filter_or("info")).init();
     sodiumoxide::init().expect("Failed to init crypto library!");
-    let db_pool = database::connect().expect("Failed to create database interface!");
+
+    let db_pool = web::Data::new(database::connect()?);
+    let captcha_manager = web::Data::new(CaptchaManager::new());
 
     let server = HttpServer::new(move || {
         App::new()
-            .data(db_pool.clone())
+            .app_data(db_pool.clone())
+            .app_data(captcha_manager.clone())
             .wrap(actix_web::middleware::Logger::new(
                 "%t: %r -> %s; %b B; %D ms",
             ))
+            .service(get_captcha)
             .service(register_user)
             .service(login_user)
             .service(put_user)
@@ -58,5 +63,7 @@ async fn main() -> std::io::Result<()> {
             .service(delete_medium)
     });
 
-    server.bind("127.0.0.1:8087")?.run().await
+    server.bind("127.0.0.1:8087")?.run().await?;
+
+    Ok(())
 }

src/routes/auth.rs

@@ -1,3 +1,4 @@
+use super::CaptchaManager;
 use crate::database;
 use crate::database::{DbConn, DbPool, User, UserInsertion};
 use crate::error::ServerError;
@@ -14,6 +15,8 @@ pub struct UserRegistration {
     pub username: String,
     pub password: String,
     pub email: Option<String>,
+    pub captcha_id: String,
+    pub answer: String,
 }
 
 /// Request body data for user login.
@@ -52,24 +55,31 @@ struct Claims {
 #[post("/users")]
 pub async fn register_user(
     db: web::Data<DbPool>,
+    captcha_manager: web::Data<CaptchaManager>,
     data: web::Json<UserRegistration>,
 ) -> Result<HttpResponse, ServerError> {
-    web::block(move || {
-        let conn = db.into_inner().get().or(Err(ServerError::Internal))?;
+    let captcha_manager = captcha_manager.into_inner();
 
-        database::insert_user(
-            &conn,
-            &data.username,
-            &UserInsertion {
-                password_hash: hash_password(&data.password).or(Err(ServerError::Internal))?,
-                email: data.email.clone(),
-            },
-        )
-        .or(Err(ServerError::Internal))
-    })
-    .await?;
+    if captcha_manager.check_captcha(&data.captcha_id, &data.answer)? {
+        web::block(move || {
+            let conn = db.into_inner().get().or(Err(ServerError::Internal))?;
 
-    Ok(HttpResponse::Ok().finish())
+            database::insert_user(
+                &conn,
+                &data.username,
+                &UserInsertion {
+                    password_hash: hash_password(&data.password).or(Err(ServerError::Internal))?,
+                    email: data.email.clone(),
+                },
+            )
+            .or(Err(ServerError::Internal))
+        })
+        .await?;
+
+        Ok(HttpResponse::Ok().finish())
+    } else {
+        Err(ServerError::Forbidden)
+    }
 }
 
 /// Update an existing user. This doesn't use a JWT for authentication but requires the client to

src/routes/captcha.rs

@@ -0,0 +1,133 @@
+use crate::error::ServerError;
+use actix_web::{get, web, HttpResponse};
+use anyhow::{anyhow, Result};
+use lazy_static::lazy_static;
+use rand::seq::SliceRandom;
+use serde::Serialize;
+use std::collections::HashMap;
+use std::sync::Mutex;
+
+// TODO/INFO: These hardcoded questions are a placeholder for a future mechanism to autogenerate
+// questions from the database. This will require a easily accissible web interface for Musicus.
+// There may also be another, better solution. However, the current framework of question-answer
+// pairs with randomly generated identifiers will most likely stay in place.
+
+/// A question to identify users as human.
+#[derive(Clone, Debug)]
+struct Question {
+    /// The question that will be sent to the client.
+    pub question: &'static str,
+
+    /// The answer that the client has to provide.
+    pub answer: &'static str,
+}
+
+lazy_static! {
+    /// All available captcha questions.
+    static ref QUESTIONS: Vec<Question> = vec![
+        Question {
+            question: "In welchem Jahr wurde Johannes Brahms geboren?",
+            answer: "1833",
+        },
+        Question {
+            question: "In welchem Jahr ist Johannes Brahms gestorben?",
+            answer: "1897",
+        },
+        Question {
+            question: "In welchem Jahr wurde Ludwig van Beethoven geboren?",
+            answer: "1770",
+        },
+        Question {
+            question: "In welchem Jahr ist Ludwig van Beethoven gestorben?",
+            answer: "1827",
+        },
+        Question {
+            question: "In welchem Jahr wurde Claude Debussy geboren?",
+            answer: "1862",
+        },
+        Question {
+            question: "In welchem Jahr ist Claude Debussy gestorben?",
+            answer: "1918",
+        },
+        Question {
+            question: "In welchem Jahr wurde Sergei Rachmaninow geboren?",
+            answer: "1873",
+        },
+        Question {
+            question: "In welchem Jahr ist Sergei Rachmaninow gestorben?",
+            answer: "1943",
+        },
+    ];
+}
+
+/// Response body data for captcha requests.
+#[derive(Clone, Debug, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct Captcha {
+    pub id: String,
+    pub question: String,
+}
+
+/// A generator and manager for captchas. This will keep track of the captchas that where created
+/// for clients and delete them, once the client has tried to solve them.
+pub struct CaptchaManager {
+    captchas: Mutex<HashMap<String, &'static Question>>,
+}
+
+impl CaptchaManager {
+    /// Create a new captcha manager.
+    pub fn new() -> Self {
+        Self {
+            captchas: Mutex::new(HashMap::new()),
+        }
+    }
+
+    /// Create a new captcha with a random ID.
+    pub fn generate_captcha(&self) -> Result<Captcha> {
+        let mut buffer = uuid::Uuid::encode_buffer();
+        let id = uuid::Uuid::new_v4().to_simple().encode_lower(&mut buffer).to_owned();
+
+        let question = QUESTIONS.choose(&mut rand::thread_rng())
+            .ok_or_else(|| anyhow!("Failed to get random question!"))?;
+
+        let captchas = &mut self.captchas.lock()
+            .or_else(|_| Err(anyhow!("Failed to aquire lock!")))?;
+
+        captchas.insert(id.clone(), question);
+
+        let captcha = Captcha {
+            id,
+            question: question.question.to_owned(),
+        };
+
+        Ok(captcha)
+    }
+
+    /// Check whether the provided answer is correct and delete the captcha eitherway.
+    pub fn check_captcha(&self, id: &str, answer: &str) -> Result<bool> {
+        let captchas = &mut self.captchas.lock()
+            .or_else(|_| Err(anyhow!("Failed to aquire lock!")))?;
+
+        let question = captchas.get(id);
+
+        let result = if let Some(question) = question {
+            let result = answer == question.answer;
+            captchas.remove(id);
+            result
+        } else {
+            false
+        };
+
+        Ok(result)
+    }
+}
+
+/// Request a new captcha.
+#[get("/captcha")]
+pub async fn get_captcha(manager: web::Data<CaptchaManager>) -> Result<HttpResponse, ServerError> {
+    let manager = manager.into_inner();
+    let captcha = manager.generate_captcha()?;
+
+    Ok(HttpResponse::Ok().json(captcha))
+}
+

src/routes/mod.rs

@@ -1,6 +1,9 @@
 pub mod auth;
 pub use auth::*;
 
+pub mod captcha;
+pub use captcha::*;
+
 pub mod ensembles;
 pub use ensembles::*;