Handle missing from/to headers + return parse error

backend/src/mail_server.rs

@@ -96,9 +96,11 @@ impl mailin::Handler for MailHandler {
     fn data_end(&mut self) -> mailin::Response {
         if let Err(e) = self.parse_mail() {
             event!(Level::WARN, "Error parsing email: {}", e);
-        }
 
-        mailin::response::OK
+            mailin::response::Response::custom(500, "Error parsing message".to_string())
+        } else {
+            mailin::response::OK
+        }
     }
 
     fn auth_plain(

backend/src/types.rs

@@ -2,6 +2,7 @@ use chrono::{DateTime, Local};
 use mail_parser::MimeHeaders;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
+use tracing::{event, Level};
 use uuid::Uuid;
 
 pub type MessageId = Uuid;
@@ -162,7 +163,17 @@ impl TryFrom<mail_parser::Message<'_>> for MailMessage {
     fn try_from(message: mail_parser::Message) -> Result<Self, Self::Error> {
         let from = match message.from() {
             mail_parser::HeaderValue::Address(addr) => addr.into(),
-            _ => return Err("Could not parse From  address header"),
+            _ => {
+                event!(
+                    Level::WARN,
+                    "Could not parse 'From' address header, setting placeholder 'from' address."
+                );
+
+                Address {
+                    name: Some("No from header".to_string()),
+                    email: Some("[email protected]".to_string()),
+                }
+            }
         };
 
         let to = match message.to() {
@@ -171,7 +182,17 @@ impl TryFrom<mail_parser::Message<'_>> for MailMessage {
                 .iter()
                 .map(|addr| addr.into())
                 .collect::<Vec<Address>>(),
-            _ => return Err("Could not parse To address header"),
+            _ => {
+                event!(
+                    Level::WARN,
+                    "Could not parse 'To' address header, setting placeholder 'to' address."
+                );
+
+                vec![Address {
+                    name: Some("No to header".to_string()),
+                    email: Some("[email protected]".to_string()),
+                }]
+            }
         };
 
         let subject = message.subject().unwrap_or_default().to_owned();