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A filesystem which allows you to mount HTTP directory listings or a single file, with a permanent cache. Now with Airsonic / Subsonic support!


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HTTPDirFS - HTTP Directory Filesystem with a permanent cache, and Airsonic / Subsonic server support!

Have you ever wanted to mount those HTTP directory listings as if it was a partition? Look no further, this is your solution. HTTPDirFS stands for Hyper Text Transfer Protocol Directory Filesystem.

The performance of the program is excellent. HTTP connections are reused through curl-multi interface. The FUSE component runs in the multithreaded mode.

There is a permanent cache system which can cache all the file segments you have downloaded, so you don't need to these segments again if you access them later. This feature is triggered by the --cache flag. This is similar to the --vfs-cache-mode full feature of rclone mount

There is support for Airsonic / Subsonic server. This allows you to mount a remote music collection locally.

If you only want to access a single file, there is also a simplified Single File Mode. This can be especially useful if the web server does not present a HTTP directory listing.


Please note if you install HTTDirFS from a repository, it can be outdated.

Debian 12 "Bookworm"

HTTPDirFS is available as a package in Debian 12 "Bookworm", If you are on Debian Bookworm, you can simply run the following command as root:

apt install httpdirfs

For more information on the status of HTTDirFS in Debian, please refer to Debian package tracker

Arch Linux

HTTPDirFS is available in the Arch User Repository.


HTTPDirFS is available in the FreeBSD Ports Collection.



Under Ubuntu 22.04 LTS, you need the following packages:

libgumbo-dev libfuse-dev libssl-dev libcurl4-openssl-dev uuid-dev help2man
libexpat1-dev pkg-config autoconf

Debian 12 "Bookworm"

Under Debian 12 "Bookworm" and newer versions, you need the following packages:

libgumbo-dev libfuse-dev libssl-dev libcurl4-openssl-dev uuid-dev help2man
libexpat1-dev pkg-config autoconf


The following dependencies are required from either pkg or ports:


gmake fusefs-libs gumbo e2fsprogs-libuuid curl expat pkgconf help2man

If you want to be ableto build the documentation ("gmake doc") you also need doxygen (devel/doxygen).


devel/gmake sysutils/fusefs-libs devel/gumbo misc/e2fsprogs-libuuid ftp/curl textproc/expat2 devel/pkgconf devel/doxygen misc/help2man

Note: If you want brotli compression support, you will need to install curl from ports and enable the option.

You can then build + install with:

sudo gmake install

Alternatively, you may use the FreeBSD ports(7) infrastructure to build HTTPDirFS from source with the modifications you need.


You need to install some packages from Homebrew:

brew install macfuse curl gumbo-parser openssl pkg-config help2man

If you want to be able to build the documentation ("make doc") you also need help2man, doxygen, and graphviz.

Build and install:

sudo make install

Apple's command-line build tools are usually installed as part of setting up Homebrew. HTTPDirFS will be installed in /usr/local.


./httpdirfs -f --cache $URL $MOUNT_POINT

An example URL would be Debian CD Image Server. The -f flag keeps the program in the foreground, which is useful for monitoring which URL the filesystem is visiting.

Useful options

HTTPDirFS options:

-u  --username          HTTP authentication username
-p  --password          HTTP authentication password
-P  --proxy             Proxy for libcurl, for more details refer to
    --proxy-username    Username for the proxy
    --proxy-password    Password for the proxy
    --cache             Enable cache (default: off)
    --cache-location    Set a custom cache location
                        (default: "${XDG_CACHE_HOME}/httpdirfs")
    --dl-seg-size       Set cache download segment size, in MB (default: 8)
                        Note: this setting is ignored if previously
                        cached data is found for the requested file.
    --max-seg-count     Set maximum number of download segments a file
                        can have. (default: 128*1024)
                        With the default setting, the maximum memory usage
                        per file is 128KB. This allows caching files up
                        to 1TB in size using the default segment size.
    --max-conns         Set maximum number of network connections that
                        libcurl is allowed to make. (default: 10)
    --retry-wait        Set delay in seconds before retrying an HTTP request
                        after encountering an error. (default: 5)
    --user-agent        Set user agent string (default: "HTTPDirFS")
    --no-range-check    Disable the built-in check for the server's support
                        for HTTP range requests
    --insecure-tls      Disable licurl TLS certificate verification by
                        setting CURLOPT_SSL_VERIFYHOST to 0
    --single-file-mode  Single file mode - rather than mounting a whole
                        directory, present a single file inside a virtual

For mounting a Airsonic / Subsonic server:

    --sonic-username    The username for your Airsonic / Subsonic server
    --sonic-password    The password for your Airsonic / Subsonic server
    --sonic-id3         Enable ID3 mode - this present the server content in
                        Artist/Album/Song layout
    --sonic-insecure    Authenticate against your Airsonic / Subsonic server
                        using the insecure username / hex encoded password

Useful FUSE options:

-d   -o debug          enable debug output (implies -f)
-f                     foreground operation
-s                     disable multi-threaded operation

Airsonic / Subsonic server support

The Airsonic / Subsonic server support is dedicated the my Debian package maintainer Jerome Charaoui.You can mount the music collection on your Airsonic / Subsonic server (*sonic), and browse them using your favourite file browser.

You simply have to supply both --sonic-username and --sonic-password to trigger the *sonic server mode. For example:

./httpdirfs -f --cache --sonic-username $USERNAME --sonic-password $PASSWORD $URL $MOUNT_POINT

You definitely want to enable the cache for this one, otherwise it is painfully slow.

There are two ways of mounting your *sonic server

  • the index mode
  • and the ID3 mode.

In the index mode, the filesystem is presented based on the listing on the Index link in your *sonic's home page.

In ID3 mode, the filesystem is presented using the following hierarchy: 0. Root

  1. Alphabetical indices of the artists' names
  2. The arists' names
  3. All of the albums by a single artist
  4. All the songs in an album.

By default, *sonic server is mounted in the index mode. If you want to mount in ID3 mode, please use the --sonic-id3 flag.

Please note that the cache feature is unaffected by how you mount your *sonic server. If you mounted your server in index mode, the cache is still valid in ID3 mode, and vice versa.

HTTPDirFS is also known to work with the following applications, which implement some or all of Subsonic API:

Single file mode

If you just want to access a single file, you can specify --single-file-mode. This effectively creates a virtual directory that contains one single file. This operating mode is similar to the unmaintained httpfs.


./httpdirfs -f --cache --single-file-mode mnt

This can be useful if the web server does not present a HTTP directory listing. This feature was implemented due to Github issue #86

Permanent cache system

You can cache the files you have accessed permanently on your hard drive by using the --cache flag. The file it caches persist across sessions.

By default, the cache files are stored under ${XDG_CACHE_HOME}/httpdirfs, which by default is ${HOME}/.cache/httpdirfs. Each HTTP directory gets its own cache folder, they are named using the escaped URL of the HTTP directory.

Once a segment of the file has been downloaded once, it won't be downloaded again.

Please note that due to the way the permanent cache system is implemented. The maximum download speed is around 15MiB/s, as measured using my localhost as the web server. However after you have accessed a file once, accessing it again will be the same speed as accessing your hard drive.

If you have any patches to make the initial download go faster, please submit a pull request.

The permanent cache system relies on sparse allocation. Please make sure your filesystem supports it. Otherwise your hard drive / SSD will get heavy I/O from cache file creation. For a list of filesystem that supports sparse allocation, please refer to Wikipedia.

Configuration file support

This program has basic support for using a configuration file. By default, the configuration file which the program reads is ${XDG_CONFIG_HOME}/httpdirfs/config, which by default is at ${HOME}/.config/httpdirfs/config. You will have to create the sub-directory and the configuration file yourself. In the configuration file, please supply one option per line. For example:

--username test
--password test

Alternatively, you can specify your own configuration file by using the --config option.

Log levels

You can control how much log HTTPDirFS outputs by setting the HTTPDIRFS_LOG_LEVEL environmental variable. For details of the different types of log that are supported, please refer to log.h and log.c.

The Technical Details

For the normal HTTP directories, this program downloads the HTML web pages/files using libcurl, then parses the listing pages using Gumbo, and presents them using libfuse.

For *sonic servers, rather than using the Gumbo parser, this program parse *sonic servers' XML responses using expat.

The cache system stores the metadata and the downloaded file into two separate directories. It uses uint8_t arrays to record which segments of the file had been downloaded.

Note that HTTPDirFS requires the server to support HTTP Range Request, some servers support this features, but does not present "Accept-Ranges: bytes in the header responses. HTTPDirFS by default checks for this header field. You can disable this check by using the --no-range-check flag.

Other projects which incorporate HTTPDirFS

Press Coverage

  • Linux Format - Issue 264, July 2020


  • First of all, I would like to thank Jerome Charaoui for being the Debian Maintainer for this piece of software. Thank you so much for packaging it!
  • I would like to thank Cosmin Gorgovan for the technical and moral support. Your wisdom is much appreciated!
  • I would like to thank Edenist for providing FreeBSD compatibility patches.
  • I would like to thank hiliev for providing macOS compatibility patches.
  • I would like to thank Jonathan Kamens for providing a whole bunch of code improvements and the improved build system.
  • I would like to thank -Archivist for not providing FTP or WebDAV access to his server. This piece of software was written in direct response to his appalling behaviour.