Suffix `/announce` is stripped from tracker url

[wichtfx]

For some reason, the suffix /announce is stripped from the tracker url when uploading a torrent.
My workflow is the following:

1. create a torrent with the /announce suffix
2. upload the torrent to torrust-index
3. the created torrent has an auth key as expected
4. the tracker url in the torrent has no /announce suffix
5. any client cannot connect to the tracker
6. if manually adding the /announce suffix the client can contact the tracker....

Here below is my config.toml:

[website]
name = "Torrust"

[metadata]
app = "torrust-index"
purpose = "configuration"
schema_version = "2.0.0"

[logging]
#threshold = "off"
#threshold = "error"
#threshold = "warn"
threshold = "info"
#threshold = "debug"
#threshold = "trace"

[tracker]
token = "redacted"
listed = false
private = true
api_url = "example.com:1212"
url = "example.com:7070"

[auth]
user_claim_token_pepper = "redacted"

[database]
connect_url = "sqlite:///var/lib/torrust/index/database/sqlite3.db?mode=rwc"

[mail.smtp]
port = 1025
server = "mailcatcher"

[registration]
[registration.email]

[tracker_statistics_importer]
torrent_info_update_interval = 3600
port = 3002

Thanks for the help

[josecelano]

Hi @wichtfx thank you for reporting. I will try to reproduce it. At first glance, it seems that it could be that you don't specify the full tracker URL in the configuration:

[tracker]
token = "redacted"
listed = false
private = true
api_url = "example.com:1212"
# this
url = "example.com:7070"

I guess it should be:

[tracker]
token = "redacted"
listed = false
private = true
api_url = "example.com:1212"
url = "http://example.com:7070/announce"

I don't remember it off the top of my head, but I think that the URL we add to the torrent without any modification.

[josecelano]

This is the configuration I use in the tracker demo (without secrets, secrets are injected with env vars).

[josecelano]

On the other hand, I have to review the code; the tracker URL is added automatically when you upload the torrent, but I don't know what happens if you already insert a tracker URL with the same authority in the URL. I guess it's replaced by the one in the configuration, but I need to check it.

[wichtfx]

Hey @josecelano , thank you for the swift answer. I don't use udp, maybe it has an influence? Let me show you my tracker config:

[metadata]
app = "torrust-tracker"
purpose = "configuration"
schema_version = "2.0.0"

[logging]
threshold = "info"

[core]
inactive_peer_cleanup_interval = 600
listed = false
private = true
tracker_usage_statistics = true

[core.database]
path = "/var/lib/torrust/tracker/database/sqlite3.db"

# Uncomment to enable services


[[http_trackers]]
bind_address = "0.0.0.0:7070"

[http_api]
bind_address = "0.0.0.0:1212"

[http_api.access_tokens]
admin = "redacted"

[core.tracker_policy]
max_peer_timeout = 900
persistent_torrent_completed_stat = true

[core.net]
external_ip = "0.0.0.0"
on_reverse_proxy = false

[wichtfx]

It is worth noting as well that my tracker is behind a reverse proxy but it should not have an impact since adding the announce suffix makes it work.

[josecelano]

It is worth noting as well that my tracker is behind a reverse proxy but it should not have an impact since adding the announce suffix makes it work.

If it works with your torrent when you use the tracker URL manually, it should also work after downloading the torrent from the index.

You have to put in the url config option the tracker URL that works for you. The one you use manually:

[tracker]
token = "redacted"
listed = false
private = true
api_url = "example.com:1212"
url = "http://example.com:7070/announce" # <- here the tracker URL that works for you.

Anyway, I will double-check it; there could be a bug using an HTTP tracker in the index. However, according to your description, it appears that it is only replacing your URL with the one in the index configuration (url = "example.com:7070"), which does not include the /announce path.

In the torrent detail page (for examplehttps://index.torrust-demo.com/torrent/2b66980093bc11806fab50cb3cb41835b95a0362/debian-1250-amd64-netinstiso), you should see the right tracker URL after uploading the torrent:

It should match the one in the configration.

[wichtfx]

I changed the url to url = "http://example.com:7070/announce", it works for the unauthenticated one but not for the one with the appended key (that still does not have the suffix)

[wichtfx]

Oh it seems that a missing / was the culprit. If one specifies url = "http://example.com:7070/announce/" with the slash at the end, that works!

[josecelano]

I've made a test.

1. Run the Index locally
2. Use the tracker demo URL in the Index: https://tracker.torrust-demo.com/announce (without trailing slash)

[tracker]
token = "MyAccessToken"
url = "https://tracker.torrust-demo.com/announce"
# ...

4. Upload a new torrent and confirm the URL is added

API response for the torrent details:

{
    "data": {
        "torrent_id": 28,
        "uploader": "admin",
        "info_hash": "2b66980093bc11806fab50cb3cb41835b95a0362",
        "title": "test",
        "description": "test",
        "category": {
            "id": 1,
            "category_id": 1,
            "name": "movies",
            "num_torrents": 1
        },
        "upload_date": "2025-06-13 20:41:34",
        "file_size": 659554304,
        "seeders": 0,
        "leechers": 0,
        "files": [
            {
                "path": [
                    "debian-12.5.0-amd64-netinst.iso"
                ],
                "length": 659554304,
                "md5sum": null
            }
        ],
        "trackers": [
            "https://tracker.torrust-demo.com/announce",
            "udp://tracker.torrust-demo.com:6969"
        ],
        "magnet_link": "magnet:?xt=urn:btih:2b66980093bc11806fab50cb3cb41835b95a0362&dn=test&tr=https%3A%2F%2Ftracker.torrust-demo.com%2Fannounce&tr=udp%3A%2F%2Ftracker.torrust-demo.com%3A6969",
        "tags": [],
        "name": "debian-12.5.0-amd64-netinst.iso",
        "comment": "\"Debian CD from cdimage.debian.org\"",
        "creation_date": 1707570148,
        "created_by": "mktorrent 1.1",
        "encoding": null,
        "canonical_info_hash_group": [
            "2b66980093bc11806fab50cb3cb41835b95a0362"
        ]
    }
}

You can load the tracker URL directly in the browser: https://tracker.torrust-demo.com/announce

You should see something like this:

Perhaps the problem lies with the proxy. Does it work for you manually with the URL without the trailing slash? I mean, if you load the torrent in your BitTorrent client with a tracker URL without a trailing slash, does it work?

You can also try loading the tracker URL directly from your server without the trailing slash, only to check if the tracker responds. That way, we could verify if the problem is in the proxy.

[wichtfx]

The discovery works now. However, I get the same error as you. Moreover,
If I put on_reverse_proxy = false the peers have the IP of the reverse proxy...
If I put on_reverse_proxy = true I get this error in my clients: error resolving peer IP: missing or invalid the right most X-forwarded_For Ip (mandatory on reverse proxy tracker configuration)

[wichtfx]

Any clue what the problem is?

[josecelano]

The discovery works now. However, I get the same error as you. Moreover, If I put on_reverse_proxy = false the peers have the IP of the reverse proxy... If I put on_reverse_proxy = true I get this error in my clients: error resolving peer IP: missing or invalid the right most X-forwarded_For Ip (mandatory on reverse proxy tracker configuration)

Hi @wichtfx, if you enable the reverse proxy option, you have to set the proxy to pass the original peer IP to the tracker. In Nginx, you can do it like this.

The error message occurs because the tracker can't retrieve the peer's IP address from the HTTP header.

[josecelano]

I changed the url to url = "http://example.com:7070/announce", it works for the unauthenticated one but not for the one with the appended key (that still does not have the suffix)

Hi @wichtfx, that's a bug :-/

The API response for torrent details:

The downloaded torrent:

{
   "announce": "https://127.0.0.1:7070/mCGfCr8nvixxA0h8B4iz0sT8V3FIQLi7",
   "announce-list": [
      [
         "https://127.0.0.1:7070/mCGfCr8nvixxA0h8B4iz0sT8V3FIQLi7"
      ],
      [
         "udp://tracker.torrust-demo.com:6969"
      ]
   ],
   "comment": "\"Debian CD from cdimage.debian.org\"",
   "created by": "mktorrent 1.1",
   "creation date": 1707570148,
   "info": {
      "length": 659554304,
      "name": "debian-12.5.0-amd64-netinst.iso",
      "piece length": 262144,
      "pieces": "<hex>B6 01 5A 2E 04 AD 4C 05 BD 88 E6 78 EA BC 6F EE 61 F2 C5 FD F1 CC F5 01 6C ...58 64 02 C9 FB A6 85 97 A3 CF 8C 47 B6 07 11 8C 28 17 C8 97 45 E9 55</hex>"
   }
}

Both the API endpoint and the downloaded torrent don't contain the /announce/ segment in the URL.

I think the bug is in this function:

/// It builds the announce url appending the user tracker key.
/// Eg: <https://tracker:7070/USER_TRACKER_KEY>
fn announce_url_with_key(&self, tracker_key: &TrackerKey) -> Url {
    self.tracker_url
        .join(&tracker_key.key)
        .expect("a tracker key should be added to the tracker base URL")
}

According to the join method documentation:

A trailing slash is significant. Without it, the last path component is considered to be a “file” name to be removed to get at the “directory” that is used as the base.

The last segment is removed if it's a file, which is the case (/announce).

I will try to fix it asap.