try fix filename encoding bug -- fails in one test

python/tests/test_account.py

@@ -436,7 +436,7 @@ class TestOnlineAccount:
 
         lp.sec("ac1: prepare and send attachment + text to ac2")
         blobdir = ac1.get_blobdir()
-        basename = "somedata.txt"  # XXX try unicode
+        basename = "somedäüta.txt"
         p = os.path.join(blobdir, basename)
         with open(p, "w") as f:
             f.write("some data")

src/mimefactory.rs

@@ -980,21 +980,18 @@ fn build_body_file(
         }
     };
 
-    let needs_ext = dc_needs_ext_header(&filename_to_send);
-
     // create mime part, for Content-Disposition, see RFC 2183.
     // `Content-Disposition: attachment` seems not to make a difference to `Content-Disposition: inline`
     // at least on tested Thunderbird and Gma'l in 2017.
     // But I've heard about problems with inline and outl'k, so we just use the attachment-type until we
     // run into other problems ...
-    let cd_value = if needs_ext {
-        format!("attachment; filename=\"{}\"", &filename_to_send)
-    } else {
-        // XXX do we need to encode filenames?
+    let cd_value = if needs_encoding(&filename_to_send) {
         format!(
             "attachment; filename*=\"{}\"",
             quoted_printable::encode_to_str(&filename_to_send)
         )
+    } else {
+        format!("attachment; filename=\"{}\"", &filename_to_send)
     };
 
     let body = std::fs::read(blob.to_abs_path())?;
@@ -1033,7 +1030,7 @@ fn is_file_size_okay(context: &Context, msg: &Message) -> bool {
  * Encode/decode header words, RFC 2047
  ******************************************************************************/
 
-pub fn dc_needs_ext_header(to_check: impl AsRef<str>) -> bool {
+pub fn needs_encoding(to_check: impl AsRef<str>) -> bool {
     let to_check = to_check.as_ref();
 
     if to_check.is_empty() {

src/mimeparser.rs

@@ -579,14 +579,23 @@ impl<'a> MimeParser<'a> {
                 //    `Content-Disposition: ... filename*=...`
                 // or `Content-Disposition: ... filename*0*=... filename*1*=... filename*2*=...`
                 // or `Content-Disposition: ... filename=...`
+                use quoted_printable::ParseMode::Robust;
 
                 let ct = mail.get_content_disposition()?;
                 let mut desired_filename = ct
                     .params
                     .iter()
                     .filter(|(key, _value)| key.starts_with("filename"))
-                    .fold(String::new(), |mut acc, (_key, value)| {
-                        acc += value;
+                    .fold(String::new(), |mut acc, (key, value)| {
+                        if key.starts_with("filename*") {
+                            quoted_printable::decode(&value, Robust)
+                                .map(|ref res| {
+                                    acc += &String::from_utf8_lossy(res);
+                                })
+                                .ok();
+                        } else {
+                            acc += value;
+                        };
                         acc
                     });