add nixos module

service.nix

@@ -0,0 +1,172 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfgPrivoxy = config.services.privoxy;
+  cfg = cfgPrivoxy.tls-wrapper;
+
+  src = ./.;
+
+  action = pkgs.writeText "privoxy-tls.action" ''
+    { +client-header-tagger{privoxy-tls-tagger} }
+    /
+    { +forward-override{forward localhost:${toString cfg.rearPort}} }
+    TAG:.*?privoxy-tls
+  '';
+  filter = pkgs.writeText "privoxy-tls.filter" ''
+    CLIENT-HEADER-TAGGER: privoxy-tls-tagger
+    s@Tagged: privoxy-tls front@$0@i
+  '';
+
+  dataDir = "/var/lib/privoxy";
+  configFile = pkgs.writeText "config.ini" ''
+    [General]
+    ProxAddr  = http://${cfgPrivoxy.listenAddress}
+    FrontPort = ${toString cfg.frontPort}
+    RearPort  = ${toString cfg.rearPort}
+    CACert    = ${dataDir}/ca.crt
+    Certdir   = /tmp
+    LogLevel  = ${cfg.logLevel}
+ 
+    [TLS NoVerify]
+    ${concatStringsSep "\n" cfg.noVerify}
+
+    [TLS Passthru]
+    ${concatStringsSep "\n" cfg.passthru}
+
+    ${cfg.extraConfig}
+  '';
+  
+  python = pkgs.python3.withPackages (p: [ p.urllib3 ]);
+
+in
+
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.privoxy.tls-wrapper = {
+      enable = mkEnableOption ''
+          TLS proxy wrapper to allow privoxy to 
+          inspect and modify HTTPS traffic.
+        '';
+
+      caCert = mkOption {
+        type = types.path;
+        description = ''
+          The CA certificate, in PEM format, that will be used
+          to reencrypt the traffic. This will be installed in
+          the local trust store.
+        '';
+      };
+
+      caKey = mkOption {
+        type = types.path;
+        description = ''
+          The CA key, in PEM format, associated to the certificate.
+          This will be copied to the privoxy-owned state directory
+          but not in the nix-store.
+        '';
+      };
+
+      frontPort = mkOption {
+        type = types.port;
+        default = 8117;
+        description = ''
+          The port the privoxy-tls front proxy will bind to.
+          This will replace the standard privoxy HTTP proxy in your settings.
+        '';
+      }; 
+
+      rearPort = mkOption {
+        type = types.port;
+        default = 8119;
+        description = ''
+          The port the privoxy-tls rear proxy will bind to.
+          This will be the proxy privoxy will forward TLS-stripped
+          HTTP traffic for reencryption.
+        '';
+      };
+
+      passthru = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "*.local" ];
+        description = ''
+          List of URLs configured for passthrough, meaning
+          the proxy will directly connect skipping privoxy.
+        '';
+      };
+
+      noVerify = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "localhost" ];
+        description = ''
+          List of URLs configured that the TLS verification
+          will ignore. For example use it for self-signed certs.
+        '';
+      };
+
+      logLevel = mkOption {
+        type = types.enum [ "DEBUG" "INFO" "WARNING" "ERROR" "CRITICAL" ];
+        default = "WARNING";
+        example = "The level of logging of privoxy-tls";
+      };
+
+      extraConfig = mkOption {
+        type = types.lines;
+        default = "";
+        example = ''
+          [Bypass URL]
+          example.com
+        '';
+        description = ''
+          Additional options that will be appended to the configuration file.
+        '';
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    # install custom CA
+    security.pki.certificateFiles = [ cfg.caCert ];
+
+    # tag traffic for the rear proxy server
+    services.privoxy.actionsFiles = [ (toString action) ];
+    services.privoxy.filterFiles  = [ (toString filter) ];
+
+    users.users.privoxy-tls = {
+      group = "privoxy";
+      home  = dataDir;
+    };
+
+    systemd.services.privoxy-tls = {
+      description = "Privoxy TLS proxy wrapper.";
+      wantedBy    = [ "multi-user.target" ];
+      after       = [ "network.target" ];
+      serviceConfig = {
+        User = "privoxy-tls";
+        PrivateTmp           = true;
+        PermissionsStartOnly = true;
+        ExecStart = "${python}/bin/python ${src}/main.py -c ${configFile}";
+      };
+      preStart = ''
+        if ! test -f ${dataDir}/ca.crt; then
+          cat ${toString cfg.caCert} ${toString cfg.caKey} > ${dataDir}/ca.crt
+        fi
+      '';
+    };
+
+  };
+
+}