fetchPypi: move to top level

fetchPypi doesn't use python under the hood and doesn't need to be tied
to a specific version of python. Moving it to top level makes it more
consistent with other fetchers and makes code generation easier.

1 files changed, 28 insertions, 0 deletions

diff --git a/pkgs/build-support/fetchpypi/default.nix b/pkgs/build-support/fetchpypi/default.nix
new file mode 100644
index 0000000000000..ebd277cd2bdf8
--- /dev/null
+++ b/pkgs/build-support/fetchpypi/default.nix
@@ -0,0 +1,28 @@
+# `fetchPypi` function for fetching artifacts from PyPI.
+{ fetchurl
+, makeOverridable
+}:
+
+let
+  computeUrl = {format ? "setuptools", ... } @attrs: let
+    computeWheelUrl = {pname, version, dist ? "py2.py3", python ? "py2.py3", abi ? "none", platform ? "any"}:
+    # Fetch a wheel. By default we fetch an universal wheel.
+    # See https://www.python.org/dev/peps/pep-0427/#file-name-convention for details regarding the optional arguments.
+      "https://files.pythonhosted.org/packages/${dist}/${builtins.substring 0 1 pname}/${pname}/${pname}-${version}-${python}-${abi}-${platform}.whl";
+
+    computeSourceUrl = {pname, version, extension ? "tar.gz"}:
+    # Fetch a source tarball.
+      "mirror://pypi/${builtins.substring 0 1 pname}/${pname}/${pname}-${version}.${extension}";
+
+    compute = (if format == "wheel" then computeWheelUrl
+      else if format == "setuptools" then computeSourceUrl
+      else throw "Unsupported format ${format}");
+
+  in compute (builtins.removeAttrs attrs ["format"]);
+
+in makeOverridable( {format ? "setuptools", sha256 ? "", hash ? "", ... } @attrs:
+  let
+    url = computeUrl (builtins.removeAttrs attrs ["sha256" "hash"]) ;
+  in fetchurl {
+    inherit url sha256 hash;
+  })