Our users can use images from external domains on LinuxFr.org. This component is a reverse-proxy / cache for these images.
The main benefits of using a proxy instead of linking directly the images are:
- No flood: images can be hosted on small servers that are not able to handle all the traffic from LinuxFr.org, so we avoid to flood them
- History: even if a server is taken down, we are able to keep serving images that are already used on our pages
- Security: on the HTTPS pages, we won't include images from other domains that are available only in HTTP, so it prevents browsers from displaying warning about unsafe pages
- Privacy: the users won't connect to the external domains, so their IP addresses won't be logged on these servers.
Side effects:
- file is changed on remote side (modified or converted into another format), new file will be served after the next fetch
- file is deleted on remote side, file won't be served after the next try to fetch
Install Go and don't forget to set $GOPATH
$ go get -v -u github.com/linuxfrorg/img-LinuxFr.org
$ img-LinuxFr.org [-a addr] [-r redis] [-l log] [-d dir] [-u agent] [-e avatar]
And, to display the help:
$ img-LinuxFr.org -h
Build and run Docker image:
$ docker build -t linuxfr.org-img .
$ docker run --publish 8000:8000 linuxfr.org-img
or
$ docker run --publish 8000:8000 --env REDIS=someredis:6379/1 linuxfr.org-img
(answer from Bruno Michel, in 2012)
Github has developed a similar service, camo, for their own usage. I used it as a source of inspiration but I prefered to redevelop a new service instead of using it for several reasons:
- It lacks some feature and particulary caching!
- It runs with a legacy version of node.js, which is not very friendly for our sysadmins.
- I plan to extend it for other usages in the future, and I prefer coding in golang than in nodejs.
- And it's a fun component to recode :p
(extracted from full LinuxFr.org Redis schema)
Key | Type | Value | Expiration | Description
-----------------------------------------------|--------|---------------------------------------------------------
img/<uri> | hash | | no | Images, with fields 'created_at': seconds since Epoch, 'status': 'Blocked' if administratively blocked (by moderation), 'type': content-type like 'image/jpeg' (set by img daemon), 'checksum': SHA1 (set by img daemon), and 'etag': etag (set by img daemon)
img/err/<uri> | string | error | no | Images in error, like "Invalid content-type", created by img daemon but removed by dlfp
img/updated/<uri> | string | modtime | 1h | Cached images, created by img daemon, value like "Thu, 12 Dec 2013 12:28:47 GMT"
Testsuite requires Hurl and docker-compose.
cd tests/
docker-compose up --build
DEBUG=1 ./img-tests.sh
The code is licensed as GNU AGPLv3. See the LICENSE file for the full license.
♡2012-2018 by Bruno Michel. Copying is an act of love. Please copy and share. 2022-2024 by Benoît Sibaud and Adrien Dorsaz.