Rclone serve http "save as"

What is the problem you are having with rclone?

When serving m4a files on http or webdav the "right click" -> "save link as"* procedure give out a mp3 file. One has to manually change the extention to m4a.
Tested in Chrome, Vivaldi and Edge, I get the same behaviour in all three of them.
Am I missing something in the configuration of the serve command ?

*I'm not sure how this is stated in English, it is "Enregistrer le lien sous..." in French in Chrome.

What is your rclone version (output from rclone version)

C:\Users\danbei>rclone version
rclone v1.56.1
- os/version: Microsoft Windows 10 Pro 2009 (64 bit)
- os/kernel: 10.0.19042.1202 (x86_64)
- os/type: windows
- os/arch: amd64
- go/version: go1.16.8
- go/linking: dynamic
- go/tags: cmount

Which cloud storage system are you using? (eg Google Drive)

I use local remote in this example

The command you were trying to run (eg rclone copy /tmp remote:tmp)

mkdir foo
type nul > foo/bar.m4a
rclone -vv serve http foo/

The rclone config contents with secrets removed.

No config file is provided to rclone in this example.

A log from the command with the -vv flag

C:\Users\danbei>rclone -vv serve http foo/
2021/09/23 23:05:49 DEBUG : rclone: Version "v1.56.1" starting with parameters ["rclone" "-vv" "serve" "http" "foo/"]
2021/09/23 23:05:49 DEBUG : Creating backend with remote "foo/"
2021/09/23 23:05:49 NOTICE: Config file "C:\\Users\\danbei\\AppData\\Roaming\\rclone\\rclone.conf" not found - using defaults
2021/09/23 23:05:49 DEBUG : fs cache: renaming cache item "foo/" to be canonical "//?/C:/Users/danbei/foo"
2021/09/23 23:05:49 INFO  : Local file system at //?/C:/Users/danbei/foo: poll-interval is not supported by this remote
2021/09/23 23:06:13 INFO  : : Serving directory
2021/09/23 23:06:16 DEBUG : bar.m4a: Open: flags=O_RDONLY
2021/09/23 23:06:16 DEBUG : bar.m4a: >Open: fd=bar.m4a (r), err=<nil>

That seems to be a browser thing and nothing related to rclone.

You can validate with wget:

etexter@seraphite Downloads % wget http://localhost:8989/bar.m4a
--2021-09-23 17:24:38--  http://localhost:8989/bar.m4a
Resolving localhost (localhost)... ::1,
Connecting to localhost (localhost)|::1|:8989... connected.
HTTP request sent, awaiting response... 200 OK
Length: 14 [audio/mpeg]
Saving to: ‘bar.m4a’

bar.m4a                                     100%[==========================================================================================>]      14  --.-KB/s    in 0s

2021-09-23 17:24:38 (2.23 MB/s) - ‘bar.m4a’ saved [14/14]

As I get the same behavior in Chrome.

Indeed no problem with wget in WSL :

$ wget http://localhost:8080/bar.m4a
--2021-09-23 23:32:38--  http://localhost:8080/bar.m4a
Resolving localhost (localhost)...
Connecting to localhost (localhost)||:8080... connected.
HTTP request sent, awaiting response... 200 OK
Length: 0 [audio/mpeg]
Saving to: ‘bar.m4a’

bar.m4a                           [ <=>                                              ]       0  --.-KB/s    in 0s

2021-09-23 23:32:38 (0.00 B/s) - ‘bar.m4a’ saved [0/0]

There is no problem downloading the file via the browser neither, it is just that the extension is changed (see 1st screen shot attached below). I'm confused because I don't get this behaviour with other http servers (see 2nd screen shot attached below).

Note that I noticed an extension change only for m4a files. I tested wav, flac, mp3 and mp4 files.

Served by rclone

Served by some apache server

If you check the browser's developer tools, does the working server return relevant headers, e.g. Content-Type, Content-Disposition, that rclone serve does not?

Here is the code of the page served by the working server, I only removed the paths. I don't know enough about html to know what to look for.

    <title>Index of /***/***/foo</title>
    <h1>Index of /***/***/foo</h1>
    <pre><img src="/***/blank.gif" alt="Icon "> <a href="?C=N;O=D">Name</a>                    
      <a href="?C=M;O=A">Last modified</a>      
      <a href="?C=S;O=A">Size</a>  
      <a href="?C=D;O=A">Description</a>
        <img src="/***/back.gif" alt="[PARENTDIR]"> 
        <a href="/***/***/">Parent Directory</a>                             -   
        <img src="/***/unknown.gif" alt="[   ]"> 
        <a href="bar.m4a">bar.m4a</a>
        2021-09-23 23:47    0

When I copy the html source of the page served by rclone into a file and open the file in my browser the behaviour is correct : m4a file are downloaded as m4a.

I can copy the source of the page served by rclone if needed.

I can reproduce the issue.

It is related to this code:

The case is that if the backend does not supply MIME information, like local filesystem, as listed here, then serve http will use the file extension and lookup in a os dependent mime database. In my test it ends up with audio/mpeg, and based on that the browser apparantly deduces .mp3 extension.

Haven't checked what mime type a working system reports, but probably audio/x-m4a og audio/mp4 or something.

This needs some more investigation...

Found the problem, think it is a bug, suggested fix here.

1 Like

Great ! thank you for your responsiveness

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