2 files changed, 11 insertions, 6 deletions
diff --git a/src/main/java/com/juick/www/api/Index.java b/src/main/java/com/juick/www/api/Index.java
index 921ebca4..7430c22d 100644
--- a/src/main/java/com/juick/www/api/Index.java
+++ b/src/main/java/com/juick/www/api/Index.java
@@ -19,6 +19,7 @@ package com.juick.www.api;
 
 import io.swagger.v3.oas.annotations.Hidden;
 
+import jakarta.validation.ConstraintViolationException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.http.HttpStatus;
@@ -56,4 +57,8 @@ public class Index {
                 ServletUriComponentsBuilder.fromCurrentRequestUri().build().toUriString());
         return ResponseEntity.badRequest().body("Invalid media type");
     }
+    @ExceptionHandler(ConstraintViolationException.class)
+    public ResponseEntity<String> badRequest(final ConstraintViolationException exception) {
+        return ResponseEntity.badRequest().body(exception.getMessage());
+    }
 }
diff --git a/src/main/java/com/juick/www/controllers/Compat.java b/src/main/java/com/juick/www/controllers/Compat.java
index 4a7390f5..edd7bc29 100644
--- a/src/main/java/com/juick/www/controllers/Compat.java
+++ b/src/main/java/com/juick/www/controllers/Compat.java
@@ -21,8 +21,10 @@ import com.juick.service.ActivityPubService;
 import com.juick.service.WebfingerService;
 import com.juick.util.HttpNotFoundException;
 import com.juick.www.api.activity.model.Context;
+import jakarta.validation.constraints.NotEmpty;
 import org.springframework.http.MediaType;
 import org.springframework.stereotype.Controller;
+import org.springframework.validation.annotation.Validated;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.servlet.mvc.support.RedirectAttributes;
@@ -31,6 +33,7 @@ import org.springframework.web.servlet.view.RedirectView;
 import javax.inject.Inject;
 
 @Controller
+@Validated
 public class Compat {
     @Inject
     private WebfingerService webfingerService;
@@ -42,12 +45,9 @@ public class Compat {
         return new RedirectView("/post");
     }
     @GetMapping("/mention")
-    public RedirectView mention(@RequestParam String username) {
+    public RedirectView mention(@RequestParam @NotEmpty(message = "Username may not be empty") String username) {
         var uri = webfingerService.discoverAccountURI(username, MediaType.valueOf(Context.ACTIVITY_MEDIA_TYPE));
-        if (!uri.toASCIIString().isEmpty()) {
-            var context = activityPubService.get(uri).orElseThrow(HttpNotFoundException::new);
-            return new RedirectView(context.getUrl());
-        }
-        throw new HttpNotFoundException();
+        var context = activityPubService.get(uri).orElseThrow(HttpNotFoundException::new);
+        return new RedirectView(context.getUrl());
     }
 }