Prevent the map in Immich from sending request to a somewhat shady third-party
from pcouy@lemmy.pierre-couy.fr to degoogle@lemmy.ml on 25 Jul 2024 11:45
https://lemmy.pierre-couy.fr/post/582905

Cross-posted from : lemmy.pierre-couy.fr/post/581642

Context : Immich default map tile provider (which gets sent a bunch of PII every time you use the map feature) is a company that I see no reason to trust. This is a follow-up to this post, with the permanent temporary fix I came up with. I will also summarize the general opinion from the comments, as well as some interesting piece of knowledge that commenters shared.

Hacky fix

This will use Nginx proxy module to build a caching proxy in front of Open Street Map’s tileserver and to serve a custom style.json for the maps.

This works well for me, since I already proxy all my services behind a single Nginx instance. It is probably possible to achieve similar results with other reverse proxies, but this would obviously need to be adapted.

Caching proxy

Inside Nginx’s http config block (usually in /etc/nginx/nginx.conf), create a cache zone (a directory that will hold cached responses from OSM) :

http {
     # You should not need to edit existing lines in the http block, only add the line below
    proxy_cache_path /var/cache/nginx/osm levels=1:2 keys_zone=osm:100m max_size=5g inactive=180d;
}

You may need to manually create the /var/cache/nginx/osm directory and set its owner to Nginx’s user (typically www-data on Debian based distros).

Customize the max_size parameter to change the maximum amount of cached data you want to store on your server. The inactive parameter will cause Nginx to discard cached data that’s not been accessed in this duration (180d ~ 6months).

Then, inside the server block that serves your Immich instance, create a new location block :

server {
    listen 443 ssl;
    server_name immich.your-domain.tld;

    # You should not need to change your existing config, only add the location block below

    location /map_proxy/ {
        proxy_pass https://tile.openstreetmap.org/;
        proxy_cache osm;
        proxy_cache_valid 180d;
        proxy_ignore_headers Cache-Control Expires;
        proxy_ssl_server_name on;
        proxy_ssl_name tile.openstreetmap.org;
        proxy_set_header Host tile.openstreetmap.org;
        proxy_set_header User-Agent "Nginx Caching Tile Proxy for self-hosters";
        proxy_set_header Cookie "";
        proxy_set_header Referer "";
    }
}

Reload Nginx (sudo systemctl reload nginx). Confirm this works by visiting https://immich.your-domain.tld/map_proxy/0/0/0.png, which should now return a world map PNG (the one from tile.openstreetmap.org/0/0/0.png )

This config ignores cache control headers from OSM and sets its own cache validity duration (proxy_cache_valid parameter). After the specified duration, the proxy will re-fetch the tiles. 6 months seem reasonable to me for the use case, and it can probably be set to a few years without it causing issues.

Besides being lighter on OSM’s servers, the caching proxy will improve privacy by only requesting tiles from upstream when loaded for the first time. This config also strips cookies and referrer before forwarding the queries to OSM, as well as set a user agent for the proxy following OSM foundation’s guidelines (according to these guidelines, you should add a contact information to this user agent)

This can probably be made to work on a different domain than the one serving your Immich instance, but this probably requires to add the appropriate headers for CORS.

Custom style.json

I came up with the following mapstyle :

{
  "version": 8,
  "name": "Immich Map",
  "sources": {
    "immich-map": {
      "type": "raster",
      "tileSize": 256,
      "tiles": [
        "https://immich.your-domain.tld/map_proxy/{z}/{x}/{y}.png"
      ]
    }
  },
  "sprite": "https://maputnik.github.io/osm-liberty/sprites/osm-liberty",
  "glyphs": "https://fonts.openmaptiles.org/{fontstack}/{range}.pbf",
  "layers": [
    {
      "id": "raster-tiles",
      "type": "raster",
      "source": "immich-map",
      "minzoom": 0,
      "maxzoom": 22
    }
  ],
  "id": "immich-map-dark"
}

Replace immich.your-domain.tld with your actual Immich domain, and remember the absolute path you save this at.

One last update to nginx’s config

Since Immich currently does not provide a way to manually edit style.json, we need to serve it from http(s). Add one more location block below the previous one :

location /map_style.json {
    alias /srv/immich/mapstyle.json;
}

Replace the alias parameter with the location where you saved the json mapstyle. After reloading nginx, your json style will be available at https://immich.your-domain.tld/map_style.json

Configure Immich to use this

For this last part, follow steps 8, 9, 10 from this guide (use the link to map_style.json for both light and dark themes). After clearing the browser or app’s cache, the map should now be loaded from your caching proxy. You can confirm this by tailing Nginx’s logs while you zoom and move around the map in Immich

Summary of comments from previous post

Self-hosting a tile server is not realistic in most cases

People who have previously worked with maps seem to confirm that there are no tile server solution lightweight enough to be self hosted by hobbyists. There is maybe some hope with generating tiles on demand, but someone with deep knowledge of the file formats involved in the process should confirm this.

Some interesting links were shared, which seem to confirm this is not realistically self-hostable with the available software :

• OSM Foundation’s policy on using their tile server
• Switch2OSM
• wiki.openstreetmap.org/…/Sequentially-generate-pl…

General sentiment about this issue

In all this part, I want to emphasize that while there seems to be a consensus, this is only based on the few comments from the previous post and may be biased by the fact that we’re discussing it on a non-mainstream platform. If you disagree with anything below, please comment this post and explain your point of view.

• Nobody declared that they had noticed the requests to a third-party server before
• A non-negligible fraction of Immich users are interested in the privacy benefits over other solutions such as Google photos. These users do not like their self-hosted services to send requests to third-party servers without warning them first
• The fix should consist of the following :
  • Clearly document the implications of enabling the map, and any feature that sends requests to third parties
  • Disable by default features that send requests to third parties (especially if it contains any form of geolocated data)
  • Provide a way to easily change the tile provider. A select menu with a few pre-configured style.json would be nice, along with a way to manually edit style.json (or at least some of its fields) directly from the Immich config page

#degoogle