feat(db): Prevent responses to closed threads

This concludes the thread-closing implementation!

src/db.rs

@@ -208,6 +208,19 @@ impl Handler<CreatePost> for DbExecutor {
 
         let conn = self.0.get()?;
 
+        let closed: bool = {
+            use schema::threads::dsl::*;
+            threads.select(closed)
+                .find(msg.0.thread_id)
+                .first(&conn)?
+        };
+
+        if closed {
+            return Err(ConverseError::ThreadClosed {
+                id: msg.0.thread_id
+            })
+        }
+
         Ok(diesel::insert_into(posts::table)
            .values(&msg.0)
            .get_result(&conn)?)

src/errors.rs

@@ -124,7 +124,7 @@ impl ResponseError for ConverseError {
         // Everything is mapped to internal server errors for now.
         match *self {
             ConverseError::ThreadClosed { id } => HttpResponse::SeeOther()
-                .header("Location", format!("/thread/{}#edit-post", id))
+                .header("Location", format!("/thread/{}#post-reply", id))
                 .finish(),
             _ => HttpResponse::build(StatusCode::INTERNAL_SERVER_ERROR)
                 .body(format!("An error occured: {}", self))