[kbss-cvut/23ava-distribution#18] Add getByUsername endpoint back to …

…OIDC-based users REST controller.

It is needed for impersonate functionality, as it needs to open the user detail.

src/main/java/cz/cvut/kbss/study/rest/OidcUserController.java

@@ -1,5 +1,6 @@
 package cz.cvut.kbss.study.rest;
 
+import cz.cvut.kbss.study.exception.NotFoundException;
 import cz.cvut.kbss.study.model.Institution;
 import cz.cvut.kbss.study.model.User;
 import cz.cvut.kbss.study.security.SecurityConstants;
@@ -9,6 +10,7 @@
 import org.springframework.http.MediaType;
 import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
@@ -40,6 +42,17 @@ public User getCurrent() {
         return userService.getCurrentUser();
     }
 
+    @PreAuthorize("hasRole('" + SecurityConstants.ROLE_ADMIN + "') or #username == authentication.name or " +
+            "hasRole('" + SecurityConstants.ROLE_USER + "') and @securityUtils.areFromSameInstitution(#username)")
+    @GetMapping(value = "/{username}", produces = MediaType.APPLICATION_JSON_VALUE)
+    public User getByUsername(@PathVariable("username") String username) {
+        final User user = userService.findByUsername(username);
+        if (user == null) {
+            throw NotFoundException.create("User", username);
+        }
+        return user;
+    }
+
     @PreAuthorize(
             "hasRole('" + SecurityConstants.ROLE_ADMIN + "') " +
                     "or hasRole('" + SecurityConstants.ROLE_USER + "') and @securityUtils.isMemberOfInstitution(#institutionKey)")