diff --git a/src/data/error.rs b/src/data/error.rs
index 65fb93c..0974f49 100644
--- a/src/data/error.rs
+++ b/src/data/error.rs
@@ -1,6 +1,7 @@
 use core::fmt;
 use serde::export::Formatter;
 use std::error;
+use std::error::Error;
 
 /// Simple rust error
 ///
@@ -9,6 +10,7 @@ use std::error;
 
 /// Simple result type
 pub type ResultExecError<E> = Result<E, ExecError>;
+pub type ResultBoxError<E> = Result<E, Box<dyn Error>>;
 
 #[derive(Debug, Clone)]
 pub struct ExecError(pub String);
diff --git a/src/data/http_error.rs b/src/data/http_error.rs
index 5f5cb57..81deede 100644
--- a/src/data/http_error.rs
+++ b/src/data/http_error.rs
@@ -27,4 +27,12 @@ impl HttpError {
             message: message.to_string()
         }
     }
+
+    /// Generate a 401 error
+    pub fn bad_request(message: &str) -> HttpError {
+        HttpError {
+            code: 401,
+            message: message.to_string()
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/data/http_request_handler.rs b/src/data/http_request_handler.rs
index a2d93ab..646f685 100644
--- a/src/data/http_request_handler.rs
+++ b/src/data/http_request_handler.rs
@@ -4,7 +4,7 @@ use crate::data::http_error::HttpError;
 use std::convert::TryFrom;
 use std::error::Error;
 use serde::Serialize;
-use crate::data::error::{ResultExecError, ExecError};
+use crate::data::error::{ResultBoxError};
 use std::collections::HashMap;
 
 /// Http request handler
@@ -76,14 +76,20 @@ impl HttpRequestHandler {
         Err(Box::try_from(actix_web::error::ErrorInternalServerError(error)).unwrap())
     }
 
+    /// Bad request
+    pub fn bad_request(&mut self, message: String) -> RequestResult {
+        self.response = Some(HttpResponse::BadRequest().json(
+            HttpError::bad_request(&message)));
+        Err(Box::try_from(actix_web::error::ErrorBadRequest(message)).unwrap())
+    }
+
     /// Get the path of the request
     pub fn request_path(&self) -> String {
         self.request.path().to_string()
     }
 
     /// Check login tokens
-    pub fn check_client_token(&mut self) -> ResultExecError<()> {
-
+    pub fn check_client_token(&mut self) -> Result<(), Box<dyn Error>> {
         println!("me = {}", self.post_string("me")?);
 
         Ok(())
@@ -95,17 +101,20 @@ impl HttpRequestHandler {
     }
 
     /// Get a post parameter
-    pub fn post_parameter(&self, name: &str) -> Result<&RequestValue, ExecError> {
-        self.body.get(name)
-            .ok_or(ExecError(format!("POST parameter {} not found in request!", name)))
+    pub fn post_parameter(&mut self, name: &str) -> ResultBoxError<&RequestValue> {
+        if !self.has_post_parameter(name) {
+            self.bad_request(format!("POST parameter '{}' not found in request!", name))?;
+        }
+
+        Ok(self.body.get(name).unwrap())
     }
 
     /// Get a post string
-    pub fn post_string(&self, name: &str) -> Result<String, ExecError> {
+    pub fn post_string(&mut self, name: &str) -> Result<String, Box<dyn Error>> {
         let param = self.post_parameter(name)?;
 
         match &param.string {
-            None => Err(ExecError(format!("{} is not a string!", name))),
+            None => Err(Box::new(actix_web::error::ErrorBadRequest(format!("{} is not a string!", name)))),
             Some(s) => Ok(s.to_string())
         }
     }