added custom error handling

src/error.rs

@@ -0,0 +1,43 @@
+use std::error::Error;
+use std::fmt;
+
+#[derive(Debug)]
+pub enum ErrorKind {
+    BadRequest(String),
+    Conflict(String),
+    ForbiddenRequest(String),
+    NotFound(String),
+    UnprocessiableRequest(String),
+    JsonError(String),
+    Other,
+}
+
+impl Error for ErrorKind {}
+
+impl fmt::Display for ErrorKind {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            ErrorKind::BadRequest(message) => {
+                write!(f, "Client error - please try again! {}", message)
+            }
+            ErrorKind::Conflict(message) => {
+                write!(f, "Client error - task is already underway! {}", message)
+            }
+            ErrorKind::ForbiddenRequest(message) => write!(
+                f,
+                "Client error - unauthorized. Please try again! {}",
+                message
+            ),
+            ErrorKind::NotFound(message) => write!(f, "Client error - not found! {}", message),
+            ErrorKind::UnprocessiableRequest(message) => write!(
+                f,
+                "Client error - the request can't be processed. Please try again! {}",
+                message
+            ),
+            ErrorKind::JsonError(message) => {
+                write!(f, "Client error - can't parse command! {}", message)
+            }
+            ErrorKind::Other => write!(f, "Other error that I did not anticipate"),
+        }
+    }
+}