1 files changed, 28 insertions, 3 deletions

diff --git a/src/types/extract.rs b/src/types/extract.rs
index 6518ca1..bb50aa7 100644
--- a/src/types/extract.rs
+++ b/src/types/extract.rs
@@ -38,7 +38,7 @@ pub struct Json<T>(pub T);
 
 #[async_trait]
 impl<T, S, B> FromRequest<S, B> for Json<T> where 
-    T: DeserializeOwned,
+    T: DeserializeOwned + Check,
     B: HttpBody + Send + 'static,
     B::Data: Send,
     B::Error: Into<BoxError>,
@@ -56,10 +56,35 @@ impl<T, S, B> FromRequest<S, B> for Json<T> where
             return Err(ResponseCode::BadRequest.msg("Invalid utf8 body"))
         };
 
-        let Ok(value) = serde_json::from_str(&string) else {
+        let Ok(value) = serde_json::from_str::<T>(&string) else {
             return Err(ResponseCode::BadRequest.msg("Invalid request body"))
         };
 
+        if let Err(msg) = value.check() {
+            return Err(ResponseCode::BadRequest.msg(&msg));
+        }
+
         Ok(Json(value))
     }
-}
\ No newline at end of file
+}
+
+pub type CheckResult = std::result::Result<(), String>;
+
+pub trait Check {
+    
+    fn check(&self) -> CheckResult;
+
+    fn assert_length(string: &str, min: usize, max: usize, message: &str) -> CheckResult {
+        if string.len() < min || string.len() > max {
+            return Err(message.to_string())
+        }
+        Ok(())
+    }
+
+    fn assert_range(number: u64, min: u64, max: u64, message: &str) -> CheckResult {
+        if number < min || number > max {
+            return Err(message.to_string())
+        }
+        Ok(())
+    }
+} 
\ No newline at end of file