fix: don't allow empty drawings to be uploaded

crates/core/src/database/questions.rs

@@ -415,6 +415,9 @@ impl DataManager {
             // this is the initial iter to check sizes, we'll do uploads after
             if drawing.len() > Self::MAXIMUM_DRAWING_SIZE {
                 return Err(Error::FileTooLarge);
+            } else if drawing.len() < 25 {
+                // if we have less than 25 bytes in a drawing, the drawing is likely blank
+                return Err(Error::FileTooSmall);
             }
         }
 

crates/core/src/model/mod.rs

@@ -43,6 +43,7 @@ pub enum Error {
     DataTooLong(String),
     DataTooShort(String),
     FileTooLarge,
+    FileTooSmall,
     UsernameInUse,
     TitleInUse,
     QuestionsDisabled,
@@ -66,6 +67,7 @@ impl Display for Error {
             Self::DataTooLong(name) => format!("Given {name} is too long!"),
             Self::DataTooShort(name) => format!("Given {name} is too short!"),
             Self::FileTooLarge => "Given file is too large".to_string(),
+            Self::FileTooSmall => "Given file is too small".to_string(),
             Self::UsernameInUse => "Username in use".to_string(),
             Self::TitleInUse => "Title in use".to_string(),
             Self::QuestionsDisabled => "You are not allowed to ask questions there".to_string(),