nuget-to-nix: support custom package sources

If the package was not restored from nuget.org (determinted by checking
the "source" field of ".nupkg.metadata"), query the custom source for
the package endpoint (the way nuget api is built we can't determine it
without an API query) and build a custom package URL to save in the
generated deps file.

pkgs/build-support/dotnet/nuget-to-nix/default.nix

@@ -6,6 +6,8 @@
 , coreutils
 , findutils
 , gnused
+, jq
+, curl
 }:
 
 runCommandLocal "nuget-to-nix" {
@@ -18,6 +20,8 @@ runCommandLocal "nuget-to-nix" {
       coreutils
       findutils
       gnused
+      jq
+      curl
     ];
   };
 

pkgs/build-support/dotnet/nuget-to-nix/nuget-to-nix.sh

@@ -13,6 +13,8 @@ pkgs=$1
 tmpfile=$(mktemp /tmp/nuget-to-nix.XXXXXX)
 trap "rm -f ${tmpfile}" EXIT
 
+declare -A nuget_sources_cache
+
 echo "{ fetchNuGet }: ["
 
 while read pkg_spec; do
@@ -21,7 +23,14 @@ while read pkg_spec; do
     sed -nE 's/.*<id>([^<]*).*/\1/p; s/.*<version>([^<+]*).*/\1/p' "$pkg_spec")
   pkg_sha256="$(nix-hash --type sha256 --flat --base32 "$(dirname "$pkg_spec")"/*.nupkg)"
 
-  echo "  (fetchNuGet { pname = \"$pkg_name\"; version = \"$pkg_version\"; sha256 = \"$pkg_sha256\"; })" >> ${tmpfile}
+  pkg_src="$(jq --raw-output '.source' "$(dirname "$pkg_spec")/.nupkg.metadata")"
+  if [[ $pkg_src != https://api.nuget.org/* ]]; then
+    pkg_source_url="${nuget_sources_cache[$pkg_src]:=$(curl --fail "$pkg_src" | jq --raw-output '.resources[] | select(."@type" == "PackageBaseAddress/3.0.0")."@id"')}"
+    pkg_url="$pkg_source_url${pkg_name,,}/${pkg_version,,}/${pkg_name,,}.${pkg_version,,}.nupkg"
+    echo "  (fetchNuGet { pname = \"$pkg_name\"; version = \"$pkg_version\"; sha256 = \"$pkg_sha256\"; url = \"$pkg_url\"; })" >> ${tmpfile}
+  else
+    echo "  (fetchNuGet { pname = \"$pkg_name\"; version = \"$pkg_version\"; sha256 = \"$pkg_sha256\"; })" >> ${tmpfile}
+  fi
 done < <(find $1 -name '*.nuspec')
 
 LC_ALL=C sort --ignore-case ${tmpfile}