backend/README.adoc

= fediblock-backend
:showtitle:
:toc: preamble
:project: fediblock-backend
:uri-base: https://schlomp.space/FediBlock/backend
:uri-branch-main: {uri-base}/src/branch/main

:uri-gcc: https://gcc.gnu.org/
:uri-clang: https://clang.llvm.org/
:uri-cmake: https://cmake.org/
:uri-catch: https://github.com/catchorg/Catch2
:uri-dpkg: https://packages.qa.debian.org/dpkg
:uri-rpm-build: http://www.rpm.org
:uri-clang-tidy: https://clang.llvm.org/extra/clang-tidy/
:uri-cgicc: https://www.gnu.org/software/cgicc/
:uri-nlohmann-json: https://nlohmann.github.io/json/
:uri-libgit2: https://libgit2.org/
:uri-libcurl: https://curl.haxx.se/libcurl/
:uri-icu: http://site.icu-project.org/
:uri-fmt: https://github.com/fmtlib/fmt
:uri-pugixml: https://pugixml.org/

*{project}* turns form data into JSON and opens a pull request on
link:https://schlomp.space/FediBlock/data[FediBlock/data]. Also included are
tools to generate a HTML list and an RSS generator.

== Usage

.nginx config
[source,nginx]
--------------------------------------------------------------------------------
# Use 100 MiB cache with a 1 MiB memory zone (enough for ~8,000 keys).
# Delete data that has not been accessed for 10 minutes.
fastcgi_cache_path /var/cache/nginx/fediblock levels=1:2 max_size=100m
                   keys_zone=fediblock:1m inactive=10m use_temp_path=off;
fastcgi_cache_key "$scheme$request_method$host$request_uri";
add_header X-Cache $upstream_cache_status;

limit_req_zone $binary_remote_addr zone=fediblock_add:10m rate=1r/m;

server {
    # […]

    expires 30m;

    location ~* "(png|jpe?g|webp|gif)$" {
        expires 6d;
    }

    location /add {
        include /etc/nginx/fastcgi_params;
        fastcgi_pass  unix:/var/run/cgi-fcgiwrap.socket-1;
        fastcgi_param SCRIPT_FILENAME /usr/bin/fediblock-backend;
        fastcgi_param HOME "/var/lib/nginx"; # When I didn't set it, HOME was /root.

        client_max_body_size 5M;
        limit_req zone=fediblock_add;
    }

    location /rss {
        include /etc/nginx/fastcgi_params;
        fastcgi_pass  unix:/var/run/cgi-fcgiwrap.socket-1;
        fastcgi_param SCRIPT_FILENAME /usr/bin/fediblock-backend-gen_rss;
        fastcgi_param HOME "/var/lib/nginx";
        fastcgi_cache fediblock;
        fastcgi_cache_valid 200 15m; # Cache answers for up to 15 minutes.
        fastcgi_cache_lock on;  # Relay only one identical request at a time.
    }

    location /api/v1/list {
        include /etc/nginx/fastcgi_params;
        fastcgi_pass  unix:/var/run/cgi-fcgiwrap.socket-1;
        fastcgi_param SCRIPT_FILENAME /usr/bin/fediblock-backend-json_api;
        fastcgi_param HOME "/var/lib/nginx";
        fastcgi_cache fediblock;
        fastcgi_cache_valid 200 15m; # Cache answers for up to 15 minutes.
        fastcgi_cache_lock on;  # Relay only one identical request at a time.
    }
}
--------------------------------------------------------------------------------

.Generate SSH key
[source,shell]
--------------------------------------------------------------------------------
sudo -u nginx ssh-keygen -t ed25519 -f ~nginx/.local/share/fediblock-backend/ssh_id
--------------------------------------------------------------------------------

Don't forget to add the key to the data repo.

Generate an access token and save it in
`~nginx/.local/share/fediblock-backend/gitea_access_token`.

[NOTE]
On non-Linux systems the data path is `~nginx/.fediblock-backend` unless
`XDG_DATA_HOME` is set.

Make sure the user that runs the CGI programs can create lockfiles. In Linux,
the locations are `/run/user/<UID>` or `/run/lock`, on UNIX the location is
`/var/run`. If none of these locations exist, `/tmp` is used as a fallback.

=== Generate HTML blocklist

After compiling, run `fediblock-backend-gen_html`. The screenshots will be
copied into the target directory and the output will be the HTML file.

.Example: Generate the HTML blocklist in `~/blocklist/`
[source,shell]
--------------------------------------------------------------------------------
fediblock-backend-gen_html ~/blocklist > ~/blocklist/index.html
--------------------------------------------------------------------------------

Existing screenshots will not be overwritten.

[NOTE]
The RSS generator expects the blocklist to be in
`http(s)://your-domain/blocklist/`.

== Install

=== From source

==== Dependencies

* Tested OS: Linux
* C\++ compiler with C++17 support (tested: link:{uri-gcc}[GCC] 7/8/9/10,
  link:{uri-clang}[clang] 6/7/10)
* link:{uri-cmake}[CMake] (at least: 3.10)
* link:{uri-cgicc}[cgicc] (tested: 3.2)
* link:{uri-nlohmann-json}[nlohmann-json] (tested: 3.7 / 2.1)
* link:{uri-libgit2}[libgit2] with SSH support (tested: 1.0 / 0.26)
* link:{uri-libcurl}[libcurl] (at least: 7.56)
* link:{uri-icu}[ICU] (tested: 67.1 / 60.2)
* link:{uri-fmt}[fmt] (tested: 7.0 / 4.0)
* link:{uri-pugixml}[pugixml] (tested: 1.10 / 1.8)
* Optional
  ** Tests: link:{uri-catch}[Catch] (tested: 2.5 / 1.10)
  ** DEB package: link:{uri-dpkg}[dpkg] (tested: 1.19)
  ** RPM package: link:{uri-rpm-build}[rpm-build] (tested: 4.11)

==== Get sourcecode

[source,shell]
--------------------------------------------------------------------------------
git clone https://schlomp.space/FediBlock/backend.git
--------------------------------------------------------------------------------

==== Compile

[source,shell]
--------------------------------------------------------------------------------
mkdir -p build && cd build
cmake ..
cmake --build . -- --jobs=$(nproc --ignore=1)
--------------------------------------------------------------------------------

.CMake options:
* `-DCMAKE_BUILD_TYPE=Debug` for a debug build.
* `-DWITH_TESTS=YES` if you want to compile the tests.
* `-DWITH_CLANG-TIDY=YES` to check the sourcecode with
  link:{uri-clang-tidy}[clang-tidy] while compiling.
* One of:
  ** `-DWITH_DEB=YES` if you want to be able to generate a deb-package.
  ** `-DWITH_RPM=YES` if you want to be able to generate an rpm-package.

To create a deb or rpm package, run `make package` after compiling.

include::{uri-base}/raw/branch/main/CONTRIBUTING.adoc[]