refactor: Refactor the CaptchaFinder and CaptchaStorage to work with token and answer as string

Signed-off-by: Awiteb <a@4rs.nl>

Cargo.toml

@@ -28,3 +28,7 @@ tempfile = "3.9"
 tokio = { version = "1.35", features = ["macros", "rt-multi-thread"] }
 base64 = "0.21"
 salvo = { version = ">= 0.65, < 0.69", default-features = false, features = ["server", "http1","http2", "affix"] }
+
+[[example]]
+name = "simple_login"
+required-features = ["cacache-storage"]

examples/simple_login.rs

@@ -3,15 +3,6 @@
 // You can see a video of this example here:
 //
 // Run the example with `cargo run --example simple_login --features cacache-storage`
-//
-// Or set up a crate for it, with the following `Cargo.toml`:
-// ```toml
-// [dependencies]
-// base64 = ">= 0.21"
-// salvo = { version = ">= 0.65", features = ["affix"] }
-// salvo-captcha = { version = ">= 0.1", features = ["cacache-storage"] }
-// tokio = { version = ">= 1.35", features = ["macros", "rt-multi-thread", "time"] }
-// ```
 
 use std::{sync::Arc, time::Duration};
 
@@ -19,9 +10,6 @@ use base64::{engine::GeneralPurpose, Engine};
 use salvo::prelude::*;
 use salvo_captcha::*;
 
-// The type of the captcha
-type MyCaptcha = Captcha<CacacheStorage, CaptchaFormFinder<String, String>>;
-
 // To convert the image to base64, to show it in the browser
 const BASE_64_ENGINE: GeneralPurpose = GeneralPurpose::new(
     &base64::alphabet::STANDARD,
@@ -29,7 +17,7 @@ const BASE_64_ENGINE: GeneralPurpose = GeneralPurpose::new(
 );
 
 #[handler]
-async fn index(_req: &mut Request, res: &mut Response, depot: &mut Depot) {
+async fn index(res: &mut Response, depot: &mut Depot) {
     // Get the captcha from the depot
     let captcha_storage = depot.obtain::<Arc<CacacheStorage>>().unwrap();
 
@@ -51,7 +39,7 @@ async fn index(_req: &mut Request, res: &mut Response, depot: &mut Depot) {
 #[handler]
 async fn auth(req: &mut Request, res: &mut Response, depot: &mut Depot) {
     // Get the captcha state from the depot, where we can know if the captcha is passed
-    let captcha_state = depot.get_captcha_state().unwrap();
+    let captcha_state = depot.get_captcha_state();
     // Not important, just for demo
     let Some(username) = req.form::<String>("username").await else {
         res.status_code(StatusCode::BAD_REQUEST);
@@ -76,7 +64,7 @@ async fn auth(req: &mut Request, res: &mut Response, depot: &mut Depot) {
 
 #[tokio::main]
 async fn main() {
-    let captcha_middleware = MyCaptcha::new(
+    let captcha_middleware = Captcha::new(
         CacacheStorage::new("./captcha-cache"),
         CaptchaFormFinder::new(),
     )
@@ -115,6 +103,7 @@ async fn main() {
         );
 
     let acceptor = TcpListener::new(("127.0.0.1", 5800)).bind().await;
+    println!("Starting server on http://127.0.0.1:5800");
     Server::new(acceptor).serve(router).await;
     captcha_cleaner.await.ok();
 }

src/captcha_gen.rs

@@ -1,3 +1,14 @@
+// Copyright (c) 2024, Awiteb <a@4rs.nl>
+//     A captcha middleware for Salvo framework.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
 use crate::{CaptchaDifficulty, CaptchaName, CaptchaStorage};
 
 /// Captcha generator, used to generate a new captcha image. This trait are implemented for all [`CaptchaStorage`].
@@ -11,7 +22,7 @@ pub trait CaptchaGenerator: CaptchaStorage {
         &self,
         name: CaptchaName,
         difficulty: CaptchaDifficulty,
-    ) -> impl std::future::Future<Output = Result<Option<(Self::Token, Vec<u8>)>, Self::Error>> + Send
+    ) -> impl std::future::Future<Output = Result<Option<(String, Vec<u8>)>, Self::Error>> + Send
     {
         async {
             let Some((captcha_answer, captcha_image)) =
@@ -20,7 +31,7 @@ pub trait CaptchaGenerator: CaptchaStorage {
                 return Ok(None);
             };
 
-            let token = self.store_answer(captcha_answer.into()).await?;
+            let token = self.store_answer(captcha_answer).await?;
             Ok(Some((token, captcha_image)))
         }
     }

src/finder.rs

@@ -9,49 +9,37 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
-use std::marker::PhantomData;
-
 use salvo_core::http::header::HeaderName;
 use salvo_core::http::Request;
 
 /// Trait to find the captcha token and answer from the request.
 pub trait CaptchaFinder: Send + Sync {
-    /// The token type
-    type Token: TryFrom<String> + Sync + Send;
-    /// The answer type
-    type Answer: TryFrom<String> + Sync + Send;
-
-    /// The token error type
-    type TError: std::fmt::Debug + Send;
-    /// The answer error type
-    type AError: std::fmt::Debug + Send;
-
     /// Find the captcha token from the request.
     ///
-    /// Return [`None`] if the request does not contain a captcha token. An error is returned if the token is invalid format.
+    /// ### Returns
+    /// - None: If the token is not found
+    /// - Some(None): If the token is found but is invalid (e.g. not a valid string)
+    /// - Some(Some(token)): If the token is found
     fn find_token(
         &self,
         req: &mut Request,
-    ) -> impl std::future::Future<Output = Result<Option<Self::Token>, Self::TError>> + std::marker::Send;
+    ) -> impl std::future::Future<Output = Option<Option<String>>> + std::marker::Send;
 
     /// Find the captcha answer from the request.
     ///
-    /// Return [`None`] if the request does not contain a captcha answer. An error is returned if the answer is invalid format.
+    /// ### Returns
+    /// - None: If the answer is not found
+    /// - Some(None): If the answer is found but is invalid (e.g. not a valid string)
+    /// - Some(Some(answer)): If the answer is found
     fn find_answer(
         &self,
         req: &mut Request,
-    ) -> impl std::future::Future<Output = Result<Option<Self::Answer>, Self::AError>> + std::marker::Send;
+    ) -> impl std::future::Future<Output = Option<Option<String>>> + std::marker::Send;
 }
 
 /// Find the captcha token and answer from the header
 #[derive(Debug)]
-pub struct CaptchaHeaderFinder<T, A>
+pub struct CaptchaHeaderFinder {
-where
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-{
-    phantom: PhantomData<(T, A)>,
-
     /// The header name of the captcha token
     ///
     /// Default: "x-captcha-token"
@@ -65,13 +53,7 @@ where
 
 /// Find the captcha token and answer from the form
 #[derive(Debug)]
-pub struct CaptchaFormFinder<T, A>
+pub struct CaptchaFormFinder {
-where
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-{
-    phantom: PhantomData<(T, A)>,
-
     /// The form name of the captcha token
     ///
     /// Default: "captcha_token"
@@ -83,11 +65,7 @@ where
     pub answer_name: String,
 }
 
-impl<T, A> CaptchaHeaderFinder<T, A>
+impl CaptchaHeaderFinder {
-where
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-{
     /// Create a new CaptchaHeaderFinder
     pub fn new() -> Self {
         Self::default()
@@ -106,11 +84,7 @@ where
     }
 }
 
-impl<T, A> CaptchaFormFinder<T, A>
+impl CaptchaFormFinder {
-where
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-{
     /// Create a new CaptchaFormFinder
     pub fn new() -> Self {
         Self::default()
@@ -129,99 +103,57 @@ where
     }
 }
 
-impl<T, A> Default for CaptchaHeaderFinder<T, A>
+impl Default for CaptchaHeaderFinder {
-where
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-{
     /// Create a default CaptchaHeaderFinder with:
     /// - token_header: "x-captcha-token"
     /// - answer_header: "x-captcha-answer"
     fn default() -> Self {
         Self {
-            phantom: PhantomData,
             token_header: HeaderName::from_static("x-captcha-token"),
             answer_header: HeaderName::from_static("x-captcha-answer"),
         }
     }
 }
 
-impl<T, A> Default for CaptchaFormFinder<T, A>
+impl Default for CaptchaFormFinder {
-where
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-{
     /// Create a default CaptchaFormFinder with:
     /// - token_name: "captcha_token"
     /// - answer_name: "captcha_answer"
     fn default() -> Self {
         Self {
-            phantom: PhantomData,
             token_name: "captcha_token".to_string(),
             answer_name: "captcha_answer".to_string(),
         }
     }
 }
 
-impl<T, A> CaptchaFinder for CaptchaHeaderFinder<T, A>
+impl CaptchaFinder for CaptchaHeaderFinder {
-where
+    async fn find_token(&self, req: &mut Request) -> Option<Option<String>> {
-    T: TryFrom<String> + Sync + Send,
-    A: TryFrom<String> + Sync + Send,
-    <T as TryFrom<String>>::Error: Send,
-    <T as TryFrom<String>>::Error: std::fmt::Debug,
-    <A as TryFrom<String>>::Error: Send,
-    <A as TryFrom<String>>::Error: std::fmt::Debug,
-{
-    type Token = T;
-    type Answer = A;
-
-    type TError = <T as TryFrom<String>>::Error;
-    type AError = <A as TryFrom<String>>::Error;
-
-    async fn find_token(&self, req: &mut Request) -> Result<Option<Self::Token>, Self::TError> {
         req.headers()
             .get(&self.token_header)
-            .and_then(|t| t.to_str().ok())
+            .map(|t| t.to_str().map(ToString::to_string).ok())
-            .map(|t| Self::Token::try_from(t.to_string()))
-            .transpose()
     }
 
-    async fn find_answer(&self, req: &mut Request) -> Result<Option<Self::Answer>, Self::AError> {
+    async fn find_answer(&self, req: &mut Request) -> Option<Option<String>> {
         req.headers()
             .get(&self.answer_header)
-            .and_then(|a| a.to_str().ok())
+            .map(|a| a.to_str().map(ToString::to_string).ok())
-            .map(|a| Self::Answer::try_from(a.to_string()))
-            .transpose()
     }
 }
 
-impl<T, A> CaptchaFinder for CaptchaFormFinder<T, A>
+impl CaptchaFinder for CaptchaFormFinder {
-where
+    async fn find_token(&self, req: &mut Request) -> Option<Option<String>> {
-    T: TryFrom<String> + Sync + Send,
+        req.form_data()
-    A: TryFrom<String> + Sync + Send,
-    <T as TryFrom<String>>::Error: Send,
-    <T as TryFrom<String>>::Error: std::fmt::Debug,
-    <A as TryFrom<String>>::Error: Send,
-    <A as TryFrom<String>>::Error: std::fmt::Debug,
-{
-    type Token = T;
-    type Answer = A;
-
-    type TError = <T as TryFrom<String>>::Error;
-    type AError = <A as TryFrom<String>>::Error;
-
-    async fn find_token(&self, req: &mut Request) -> Result<Option<Self::Token>, Self::TError> {
-        req.form::<String>(&self.token_name)
             .await
-            .map(|t| Self::Token::try_from(t.to_string()))
+            .map(|form| form.fields.get(&self.token_name).cloned())
-            .transpose()
+            .ok()
     }
 
-    async fn find_answer(&self, req: &mut Request) -> Result<Option<Self::Answer>, Self::AError> {
+    async fn find_answer(&self, req: &mut Request) -> Option<Option<String>> {
-        req.form::<String>(&self.answer_name)
+        req.form_data()
             .await
-            .map(|a| Self::Answer::try_from(a.to_string()))
+            .map(|form| form.fields.get(&self.answer_name).cloned())
-            .transpose()
+            .ok()
     }
 }
 
@@ -234,77 +166,90 @@ mod tests {
 
     #[tokio::test]
     async fn test_captcha_header_finder() {
-        let finder = CaptchaHeaderFinder::<String, String>::new();
+        let finder = CaptchaHeaderFinder::new();
         let mut req = Request::default();
         let headers = req.headers_mut();
-        let token = uuid::Uuid::new_v4();
+
         headers.insert(
             HeaderName::from_static("x-captcha-token"),
-            HeaderValue::from_str(&token.to_string()).unwrap(),
+            HeaderValue::from_str("token").unwrap(),
         );
         headers.insert(
             HeaderName::from_static("x-captcha-answer"),
             HeaderValue::from_static("answer"),
         );
+
         assert_eq!(
             finder.find_token(&mut req).await,
-            Ok(Some(token.to_string()))
+            Some(Some("token".to_owned()))
         );
-        assert!(matches!(
+        assert_eq!(
             finder.find_answer(&mut req).await,
-            Ok(Some(a)) if a == *"answer"
+            Some(Some("answer".to_owned()))
-        ));
+        );
     }
 
     #[tokio::test]
     async fn test_captcha_header_finder_customized() {
-        let finder = CaptchaHeaderFinder::<String, String>::new()
+        let finder = CaptchaHeaderFinder::new()
             .token_header(HeaderName::from_static("token"))
             .answer_header(HeaderName::from_static("answer"));
+
         let mut req = Request::default();
         let headers = req.headers_mut();
-        let token = uuid::Uuid::new_v4();
+
         headers.insert(
             HeaderName::from_static("token"),
-            HeaderValue::from_str(&token.to_string()).unwrap(),
+            HeaderValue::from_str("token").unwrap(),
         );
         headers.insert(
             HeaderName::from_static("answer"),
             HeaderValue::from_static("answer"),
         );
+
         assert_eq!(
             finder.find_token(&mut req).await,
-            Ok(Some(token.to_string()))
+            Some(Some("token".to_owned()))
         );
-        assert!(matches!(
+        assert_eq!(
             finder.find_answer(&mut req).await,
-            Ok(Some(a)) if a == *"answer"
+            Some(Some("answer".to_owned()))
-        ));
+        );
     }
 
     #[tokio::test]
     async fn test_captcha_header_finder_none() {
-        let finder = CaptchaHeaderFinder::<String, String>::new();
+        let finder = CaptchaHeaderFinder::new();
         let mut req = Request::default();
 
-        assert_eq!(finder.find_token(&mut req).await, Ok(None));
+        assert_eq!(finder.find_token(&mut req).await, None);
-        assert_eq!(finder.find_answer(&mut req).await, Ok(None));
+        assert_eq!(finder.find_answer(&mut req).await, None);
     }
 
     #[tokio::test]
     async fn test_captcha_header_finder_customized_none() {
-        let finder = CaptchaHeaderFinder::<String, String>::new()
+        let finder = CaptchaHeaderFinder::new()
             .token_header(HeaderName::from_static("token"))
             .answer_header(HeaderName::from_static("answer"));
         let mut req = Request::default();
+        let headers = req.headers_mut();
 
-        assert_eq!(finder.find_token(&mut req).await, Ok(None));
+        headers.insert(
-        assert_eq!(finder.find_answer(&mut req).await, Ok(None));
+            HeaderName::from_static("x-captcha-token"),
+            HeaderValue::from_str("token").unwrap(),
+        );
+        headers.insert(
+            HeaderName::from_static("x-captcha-answer"),
+            HeaderValue::from_static("answer"),
+        );
+
+        assert_eq!(finder.find_token(&mut req).await, None);
+        assert_eq!(finder.find_answer(&mut req).await, None);
     }
 
     #[tokio::test]
     async fn test_captcha_form_finder() {
-        let finder = CaptchaFormFinder::<String, String>::new();
+        let finder = CaptchaFormFinder::new();
         let mut req = Request::default();
         *req.body_mut() = ReqBody::Once("captcha_token=token&captcha_answer=answer".into());
         let headers = req.headers_mut();
@@ -315,17 +260,17 @@ mod tests {
 
         assert_eq!(
             finder.find_token(&mut req).await,
-            Ok(Some("token".to_string()))
+            Some(Some("token".to_owned()))
         );
-        assert!(matches!(
+        assert_eq!(
             finder.find_answer(&mut req).await,
-            Ok(Some(a)) if a == *"answer"
+            Some(Some("answer".to_owned()))
-        ));
+        );
     }
 
     #[tokio::test]
     async fn test_captcha_form_finder_customized() {
-        let finder = CaptchaFormFinder::<String, String>::new()
+        let finder = CaptchaFormFinder::new()
             .token_name("token".to_string())
             .answer_name("answer".to_string());
         let mut req = Request::default();
@@ -338,17 +283,17 @@ mod tests {
 
         assert_eq!(
             finder.find_token(&mut req).await,
-            Ok(Some("token".to_string()))
+            Some(Some("token".to_owned()))
         );
-        assert!(matches!(
+        assert_eq!(
             finder.find_answer(&mut req).await,
-            Ok(Some(a)) if a == *"answer"
+            Some(Some("answer".to_owned()))
-        ));
+        );
     }
 
     #[tokio::test]
     async fn test_captcha_form_finder_none() {
-        let finder = CaptchaFormFinder::<String, String>::new();
+        let finder = CaptchaFormFinder::new();
         let mut req = Request::default();
         *req.body_mut() = ReqBody::Once("".into());
         let headers = req.headers_mut();
@@ -357,13 +302,13 @@ mod tests {
             HeaderValue::from_str(&ContentType::form_url_encoded().to_string()).unwrap(),
         );
 
-        assert_eq!(finder.find_token(&mut req).await, Ok(None));
+        assert_eq!(finder.find_token(&mut req).await, Some(None));
-        assert_eq!(finder.find_answer(&mut req).await, Ok(None));
+        assert_eq!(finder.find_answer(&mut req).await, Some(None));
     }
 
     #[tokio::test]
     async fn test_captcha_form_finder_customized_none() {
-        let finder = CaptchaFormFinder::<String, String>::new()
+        let finder = CaptchaFormFinder::new()
             .token_name("token".to_string())
             .answer_name("answer".to_string());
         let mut req = Request::default();
@@ -374,13 +319,13 @@ mod tests {
             HeaderValue::from_str(&ContentType::form_url_encoded().to_string()).unwrap(),
         );
 
-        assert_eq!(finder.find_token(&mut req).await, Ok(None));
+        assert_eq!(finder.find_token(&mut req).await, Some(None));
-        assert_eq!(finder.find_answer(&mut req).await, Ok(None));
+        assert_eq!(finder.find_answer(&mut req).await, Some(None));
     }
 
     #[tokio::test]
     async fn test_captcha_form_finder_invalid() {
-        let finder = CaptchaFormFinder::<String, String>::new();
+        let finder = CaptchaFormFinder::new();
         let mut req = Request::default();
         *req.body_mut() = ReqBody::Once("captcha_token=token&captcha_answer=answer".into());
         let headers = req.headers_mut();
@@ -389,7 +334,7 @@ mod tests {
             HeaderValue::from_str(&ContentType::json().to_string()).unwrap(),
         );
 
-        assert_eq!(finder.find_token(&mut req).await, Ok(None));
+        assert_eq!(finder.find_token(&mut req).await, None);
-        assert_eq!(finder.find_answer(&mut req).await, Ok(None));
+        assert_eq!(finder.find_answer(&mut req).await, None);
     }
 }

src/lib.rs

@@ -36,7 +36,7 @@ pub const CAPTCHA_STATE_KEY: &str = "::salvo_captcha::captcha_state";
 pub struct Captcha<S, F>
 where
     S: CaptchaStorage,
-    F: CaptchaFinder<Token = S::Token, Answer = S::Answer>,
+    F: CaptchaFinder,
 {
     /// The captcha finder, used to find the captcha token and answer from the request.
     finder: F,
@@ -47,20 +47,20 @@ where
 }
 
 /// The captcha states of the request
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Default, Debug, Clone, Copy, PartialEq, Eq)]
 pub enum CaptchaState {
+    /// The captcha check is skipped. This depends on the skipper.
+    #[default]
+    Skipped,
     /// The captcha is checked and passed. If the captcha is passed, it will be cleared from the storage.
     Passed,
-    /// The captcha check is skipped. This depends on the skipper.
-    Skipped,
     /// Can't find the captcha token in the request
     TokenNotFound,
     /// Can't find the captcha answer in the request
     AnswerNotFound,
-    /// The captcha token is wrong, can't find the captcha in the storage.
+    /// Can't find the captcha token in the storage or the token is wrong (not valid string)
-    /// Maybe the captcha token entered by the user is wrong, or the captcha is expired, because the storage has been cleared.
     WrongToken,
-    /// The captcha answer is wrong. This will not clear the captcha from the storage.
+    /// Can't find the captcha answer in the storage or the answer is wrong (not valid string)
     WrongAnswer,
     /// Storage error
     StorageError,
@@ -69,13 +69,13 @@ pub enum CaptchaState {
 impl<S, F> Captcha<S, F>
 where
     S: CaptchaStorage,
-    F: CaptchaFinder<Token = S::Token, Answer = S::Answer>,
+    F: CaptchaFinder,
 {
     /// Create a new Captcha
-    pub fn new(storage: impl Into<S>, finder: impl Into<F>) -> Self {
+    pub fn new(storage: S, finder: F) -> Self {
         Self {
-            finder: finder.into(),
+            finder,
-            storage: storage.into(),
+            storage,
             skipper: Box::new(none_skipper),
         }
     }
@@ -94,19 +94,22 @@ where
 
 /// The captcha extension of the depot.
 /// Used to get the captcha info from the depot.
-#[easy_ext::ext(CaptchaDepotExt)]
+pub trait CaptchaDepotExt {
-impl Depot {
     /// Get the captcha state from the depot
-    pub fn get_captcha_state(&self) -> Option<&CaptchaState> {
+    fn get_captcha_state(&self) -> CaptchaState;
-        self.get(CAPTCHA_STATE_KEY).ok()
+}
+
+impl CaptchaDepotExt for Depot {
+    fn get_captcha_state(&self) -> CaptchaState {
+        self.get(CAPTCHA_STATE_KEY).cloned().unwrap_or_default()
     }
 }
 
-#[async_trait::async_trait]
+#[salvo_core::async_trait]
 impl<S, F> Handler for Captcha<S, F>
 where
     S: CaptchaStorage,
-    F: CaptchaFinder<Token = S::Token, Answer = S::Answer> + 'static,
+    F: CaptchaFinder + 'static, // why?
 {
     async fn handle(
         &self,
@@ -122,28 +125,28 @@ where
         }
 
         let token = match self.finder.find_token(req).await {
-            Ok(Some(token)) => token,
+            Some(Some(token)) => token,
-            Ok(None) => {
+            Some(None) => {
                 log::info!("Captcha token is not found in request");
                 depot.insert(CAPTCHA_STATE_KEY, CaptchaState::TokenNotFound);
                 return;
             }
-            Err(err) => {
+            None => {
-                log::error!("Failed to find captcha token from request: {err:?}");
+                log::error!("Invalid token found in request");
                 depot.insert(CAPTCHA_STATE_KEY, CaptchaState::WrongToken);
                 return;
             }
         };
 
         let answer = match self.finder.find_answer(req).await {
-            Ok(Some(answer)) => answer,
+            Some(Some(answer)) => answer,
-            Ok(None) => {
+            Some(None) => {
                 log::info!("Captcha answer is not found in request");
                 depot.insert(CAPTCHA_STATE_KEY, CaptchaState::AnswerNotFound);
                 return;
             }
-            Err(err) => {
+            None => {
-                log::error!("Failed to find captcha answer from request: {err:?}");
+                log::error!("Invalid answer found in request");
                 depot.insert(CAPTCHA_STATE_KEY, CaptchaState::WrongAnswer);
                 return;
             }

src/storage.rs

@@ -26,24 +26,20 @@ pub trait CaptchaStorage: Send + Sync + 'static
 where
     Self: Clone + std::fmt::Debug,
 {
-    /// The token type
-    type Token: TryFrom<String> + std::fmt::Display + Send + Sync;
-    /// The answer type
-    type Answer: std::cmp::PartialEq + From<String> + Send + Sync;
     /// The error type of the storage.
     type Error: std::fmt::Display + std::fmt::Debug + Send;
 
     /// Store the captcha token and answer.
     fn store_answer(
         &self,
-        answer: Self::Answer,
+        answer: String,
-    ) -> impl std::future::Future<Output = Result<Self::Token, Self::Error>> + Send;
+    ) -> impl std::future::Future<Output = Result<String, Self::Error>> + Send;
 
     /// Returns the answer of the captcha token. This method will return None if the token is not exist.
     fn get_answer(
         &self,
-        token: &Self::Token,
+        token: &str,
-    ) -> impl std::future::Future<Output = Result<Option<Self::Answer>, Self::Error>> + Send;
+    ) -> impl std::future::Future<Output = Result<Option<String>, Self::Error>> + Send;
 
     /// Clear the expired captcha.
     fn clear_expired(
@@ -54,7 +50,7 @@ where
     /// Clear the captcha by token.
     fn clear_by_token(
         &self,
-        token: &Self::Token,
+        token: &str,
     ) -> impl std::future::Future<Output = Result<(), Self::Error>> + Send;
 }
 
@@ -86,19 +82,17 @@ impl CacacheStorage {
 #[cfg(feature = "cacache-storage")]
 impl CaptchaStorage for CacacheStorage {
     type Error = cacache::Error;
-    type Token = String;
-    type Answer = String;
 
-    async fn store_answer(&self, answer: Self::Answer) -> Result<Self::Token, Self::Error> {
+    async fn store_answer(&self, answer: String) -> Result<String, Self::Error> {
         let token = uuid::Uuid::new_v4();
         log::info!("Storing captcha answer to cacache for token: {token}");
         cacache::write(&self.cache_dir, token.to_string(), answer.as_bytes()).await?;
         Ok(token.to_string())
     }
 
-    async fn get_answer(&self, token: &Self::Token) -> Result<Option<Self::Answer>, Self::Error> {
+    async fn get_answer(&self, token: &str) -> Result<Option<String>, Self::Error> {
         log::info!("Getting captcha answer from cacache for token: {token}");
-        match cacache::read(&self.cache_dir, token.to_string()).await {
+        match cacache::read(&self.cache_dir, token).await {
             Ok(answer) => {
                 log::info!("Captcha answer is exist in cacache for token: {token}");
                 Ok(Some(
@@ -120,7 +114,7 @@ impl CaptchaStorage for CacacheStorage {
     async fn clear_expired(&self, expired_after: Duration) -> Result<(), Self::Error> {
         let now = SystemTime::now()
             .duration_since(std::time::UNIX_EPOCH)
-            .expect("SystemTime must be later than UNIX_EPOCH")
+            .expect("SystemTime before UNIX EPOCH!")
             .as_millis();
         let expired_after = expired_after.as_millis();
 
@@ -143,10 +137,10 @@ impl CaptchaStorage for CacacheStorage {
         Ok(())
     }
 
-    async fn clear_by_token(&self, token: &Self::Token) -> Result<(), Self::Error> {
+    async fn clear_by_token(&self, token: &str) -> Result<(), Self::Error> {
         log::info!("Clearing captcha token from cacache: {token}");
         let remove_opts = cacache::RemoveOpts::new().remove_fully(true);
-        remove_opts.remove(&self.cache_dir, token.to_string()).await
+        remove_opts.remove(&self.cache_dir, token).await
     }
 }
 
@@ -155,20 +149,18 @@ where
     T: CaptchaStorage,
 {
     type Error = T::Error;
-    type Token = T::Token;
-    type Answer = T::Answer;
 
     fn store_answer(
         &self,
-        answer: Self::Answer,
+        answer: String,
-    ) -> impl std::future::Future<Output = Result<Self::Token, Self::Error>> + Send {
+    ) -> impl std::future::Future<Output = Result<String, Self::Error>> + Send {
         self.as_ref().store_answer(answer)
     }
 
     fn get_answer(
         &self,
-        token: &Self::Token,
+        token: &str,
-    ) -> impl std::future::Future<Output = Result<Option<Self::Answer>, Self::Error>> + Send {
+    ) -> impl std::future::Future<Output = Result<Option<String>, Self::Error>> + Send {
         self.as_ref().get_answer(token)
     }
 
@@ -181,7 +173,7 @@ where
 
     fn clear_by_token(
         &self,
-        token: &Self::Token,
+        token: &str,
     ) -> impl std::future::Future<Output = Result<(), Self::Error>> + Send {
         self.as_ref().clear_by_token(token)
     }
@@ -281,7 +273,7 @@ mod tests {
             .expect("failed to check if token is exist")
             .is_some());
         assert!(storage
-            .get_answer(&"token".to_owned())
+            .get_answer("token")
             .await
             .expect("failed to check if token is exist")
             .is_none());
@@ -308,7 +300,7 @@ mod tests {
             Some("answer".to_owned())
         );
         assert!(storage
-            .get_answer(&"token".to_owned())
+            .get_answer("token")
             .await
             .expect("failed to get captcha answer")
             .is_none());