nix: add selfoss Nix package

Build client part using napalm and fetch dependencies for the server part using C4.

Author: jtojnar

flake.lock

@@ -2,6 +2,9 @@
   description = "selfoss feed reader and aggregator";
 
   inputs = {
+    # Tool for downloading Composer dependencies using Nix.
+    c4.url = "github:fossar/composition-c4";
+
     # Shim to make flake.nix work with stable Nix.
     flake-compat = {
       url = "github:edolstra/flake-compat";
@@ -11,13 +14,18 @@
     # Repository with software packages.
     nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
 
+    napalm = {
+      url = "github:nmattia/napalm";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     utils.url = "github:numtide/flake-utils";
 
     # Package expression for old PHP versions.
     phps.url = "github:fossar/nix-phps";
   };
 
-  outputs = { self, flake-compat, nixpkgs, phps, utils }:
+  outputs = { self, c4, flake-compat, napalm, nixpkgs, phps, utils }:
     let
       # Configure the development shell here (e.g. for CI).
 
@@ -28,7 +36,16 @@
       utils.lib.eachDefaultSystem (system:
         let
           # Get Nixpkgs packages for current platform.
-          pkgs = nixpkgs.legacyPackages.${system};
+          pkgs = import nixpkgs {
+            inherit system;
+            overlays = [
+              # Include c4 tool.
+              c4.overlay
+
+              # Include napalm tool.
+              napalm.overlay
+            ];
+          };
 
           # Create a PHP package from the selected PHP package, with some extra extensions enabled.
           php = phps.packages.${system}.${matrix.phpPackage}.withExtensions ({ enabled, all }: with all; enabled ++ [
@@ -69,6 +86,36 @@
             # node-gyp wants some locales, let’s make them available through an environment variable.
             LOCALE_ARCHIVE = "${pkgs.glibcLocales}/lib/locale/locale-archive";
           };
+
+          packages = {
+            selfoss =
+              let
+                filteredSrc = builtins.path {
+                  path = ./.;
+                  filter =
+                    path:
+                    type:
+                    !builtins.elem (builtins.baseNameOf path) [
+                      # These should not be part of the source code for packages built by Nix.
+                      # Otherwise, iterating on Nix files will trigger a rebuild all the time since the source will have changed.
+                      "flake.nix"
+                      "flake.lock"
+                      "utils"
+                      # CI changes should not affect it either.
+                      ".github"
+                    ];
+                    # Unfortunately, it still triggers a rebuild since any change will cause the flake to be re-cloned.
+                    # https://github.com/NixOS/nix/issues/3732
+                };
+
+                # Due to Nix bug, we cannot actually use the output directly and need to copy it to a new derivation.
+                # https://github.com/NixOS/nix/issues/3234
+                src = pkgs.runCommand "selfoss-src" {} "cp -r '${filteredSrc}' $out";
+              in
+              pkgs.callPackage ./utils/selfoss.nix rec {
+                inherit src;
+              };
+          };
         }
       );
 }

flake.nix

@@ -0,0 +1,100 @@
+{
+  stdenv,
+  napalm,
+  runCommand,
+  jq,
+  lib,
+  src,
+  c4,
+  php,
+}:
+
+let
+  version = (lib.importJSON (src + "/package.json")).ver;
+
+  client-src =
+    runCommand "client-src" {
+      nativeBuildInputs = [
+        jq
+      ];
+    } ''
+      cp -r "${src}/assets" "$out"
+      chmod +w "$out"
+
+      # napalm requires version for all packages.
+      # And npm needs it to follow semver.
+      jq '. += { "name": "selfoss-client", "version": "0.0.0+${version}" }' "$out/package-lock.json" > "$out/package-lock.json.tmp"
+      mv "$out/package-lock.json.tmp" "$out/package-lock.json"
+
+      jq '. += { "name": "selfoss-client", "version": "0.0.0+${version}" }' "$out/package.json" > "$out/package.json.tmp"
+      mv "$out/package.json.tmp" "$out/package.json"
+    '';
+
+  stopNpmCallingHome = ''
+    # Do not try to find npm in napalm-registry –
+    # it is not there and checking will slow down the build.
+    npm config set update-notifier false
+
+    # Same for security auditing, it does not make sense in the sandbox.
+    npm config set audit false
+  '';
+
+  client-assets = napalm.buildPackage "${client-src}" {
+    npmCommands = [
+      # Just download and unpack all the npm packages,
+      # we need napalm to patch shebangs before we can run install scripts.
+      "npm install --loglevel verbose --ignore-scripts"
+      # Let’s install again, this time running scripts.
+      "npm install --loglevel verbose"
+
+      # napalm only patches shebangs for scripts in bin directories
+      "patchShebangs node_modules/parcel/lib/bin.js"
+
+      # Build the front-end.
+      "npm run build"
+    ];
+
+    postConfigure = stopNpmCallingHome;
+
+    installPhase = ''
+      runHook preInstall
+
+      mv ../public $out
+
+      runHook postInstall
+    '';
+  };
+in
+stdenv.mkDerivation {
+  pname = "selfoss";
+  inherit version;
+
+  inherit src;
+
+  composerDeps = c4.fetchComposerDeps {
+    inherit src;
+  };
+
+  nativeBuildInputs = [
+    c4.composerSetupHook
+    php.packages.composer
+  ];
+
+  buildPhase = ''
+    runHook preBuild
+
+    cp -r ${client-assets} public
+    composer install --no-dev --optimize-autoloader
+
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out
+    cp -r . $out
+
+    runHook postInstall
+  '';
+}