diff --git a/pkgs/development/interpreters/ruby/fixes.nix b/pkgs/development/interpreters/ruby/fixes.nix
index 5a2b105adce..0b8545090c5 100644
--- a/pkgs/development/interpreters/ruby/fixes.nix
+++ b/pkgs/development/interpreters/ruby/fixes.nix
@@ -18,7 +18,7 @@
 # (to make gems behave if necessary).
 
 { lib, fetchurl, writeScript, ruby, libxml2, libxslt, python, stdenv, which
-, libiconv, postgresql, v8_3_16_14, clang }:
+, libiconv, postgresql, v8_3_16_14, clang, sqlite, zlib, imagemagick, pkgconfig}:
 
 let
   v8 = v8_3_16_14;
diff --git a/pkgs/development/interpreters/ruby/gem.nix b/pkgs/development/interpreters/ruby/gem.nix
index 85fa9d10cb5..a6b5dc51057 100644
--- a/pkgs/development/interpreters/ruby/gem.nix
+++ b/pkgs/development/interpreters/ruby/gem.nix
@@ -1,4 +1,4 @@
-{ ruby, fetchurl, rake, rubygemsFun, makeWrapper, lib, git }:
+{ ruby, fetchurl, rubygemsFun, makeWrapper, lib, git }:
 
 { name
 , namePrefix ? "${ruby.name}" + "-"
diff --git a/pkgs/development/interpreters/ruby/load-ruby-env.nix b/pkgs/development/interpreters/ruby/load-ruby-env.nix
index b73a9df9f83..9e60e574b37 100644
--- a/pkgs/development/interpreters/ruby/load-ruby-env.nix
+++ b/pkgs/development/interpreters/ruby/load-ruby-env.nix
@@ -1,4 +1,4 @@
-{ pkgs, lib, callPackage, gemFixes }:
+{ pkgs, lib, callPackage, gemFixes, fetchurl }:
 
 { gemset, ruby ? pkgs.ruby, fixes ? gemFixes }@args:
 
@@ -7,19 +7,31 @@ let
 
   buildRubyGem = callPackage ./gem.nix { inherit ruby; };
 
-  instantiate = (name: attrs:
+  fetchers.gem = attrs: fetchurl {
+    url = "${attrs.src.source or "https://rubygems.org"}/downloads/${attrs.name}-${attrs.version}.gem";
+    inherit (attrs.src) sha256;
+  };
+
+  instantiate = (attrs:
     let
       gemPath = map (name: gemset''."${name}") (attrs.dependencies or []);
-      fixedAttrs = attrs // (fixes."${name}" or (const {})) attrs;
+      fixedAttrs = attrs // (fixes."${attrs.name}" or (const {})) attrs;
     in
-      buildRubyGem (fixedAttrs // { name = "${name}-${attrs.version}"; inherit gemPath; })
+      buildRubyGem (
+        fixedAttrs // {
+          name = "${attrs.name}-${attrs.version}";
+          src = fetchers."${attrs.src.type}" attrs;
+          inherit gemPath;
+        }
+      )
   );
 
   gemset' = if builtins.isAttrs gemset then gemset else callPackage gemset { };
 
   gemset'' = lib.flip lib.mapAttrs gemset' (name: attrs:
-    if (lib.isDerivation attrs) then attrs
-    else (instantiate name attrs)
+    if (lib.isDerivation attrs)
+      then attrs
+      else instantiate (attrs // { inherit name; })
   );
 
 in gemset''
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 515424a4068..3209a246f62 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4049,8 +4049,6 @@ let
 
   loadRubyEnv = callPackage ../development/interpreters/ruby/load-ruby-env.nix { };
 
-  rake = ... # TODO
-
   rubySqlite3 = callPackage ../development/ruby-modules/sqlite3 { };
 
   rubygemsFun = ruby: builderDefsPackage (import ../development/interpreters/ruby/rubygems.nix) {