Add compatibility middleware

2 files changed, 21 insertions, 0 deletions

diff --git a/src/middleware/find_mailboxes_compatibility.rs b/src/middleware/find_mailboxes_compatibility.rs
new file mode 100644
index 0000000..f1a450b
--- /dev/null
+++ b/src/middleware/find_mailboxes_compatibility.rs
@@ -0,0 +1,14 @@
+use log::debug;
+
+/// MailDrop can't find folders to sync because it sends FIND MAILBOXES /*
+/// which is not understood by modern servers. It instead replaces it with
+/// a LIST command.
+pub fn middleware(input: &[u8]) -> Vec<u8> {
+    let command = String::from_utf8_lossy(input);
+    if let Some(tag) = command.split("FIND MAILBOXES /*").next() {
+        let replacement = format!("{} LIST \"/INBOX\" \"*\"\r\n", tag.trim());
+        debug!("### {replacement}");
+        return replacement.into_bytes();
+    }
+    return input.to_vec();
+}
diff --git a/src/middleware/mod.rs b/src/middleware/mod.rs
new file mode 100644
index 0000000..a1070f4
--- /dev/null
+++ b/src/middleware/mod.rs
@@ -0,0 +1,7 @@
+mod find_mailboxes_compatibility;
+
+use find_mailboxes_compatibility::middleware as find_mailboxes_compatibility_middleware;
+
+type Middleware = fn(&[u8]) -> Vec<u8>;
+
+pub const MIDDLEWARE: [Middleware; 1] = [find_mailboxes_compatibility_middleware];