Use dotnet pack with nuspec file

My understanding has always been that when packaging a library in a nuget package, I had 2 options available:

• Option 1 - Using a nuspec file with nuget pack command
• Option 2 - Using a csproj file with dotnet pack command

Turns out I was wrong. So I want to use this post to explain where I was wrong. But before I do that let me dive into the 2 options above…

Using a nuspec file with nuget pack

One option you have is to put all the metadata for your nuget package inside a nuspec file. Here is how such a file can look like:

	<?xml version="1.0" encoding="utf-8"?>
	<package>
	<id>Example</id>
	<version>1.0.0</version>
	<title>Example Lib</title>
	<authors>Bart Wullems</authors>
	<description>Hello world</description>
	<contentFiles>
	<files include="*" />
	</contentFiles>
	</metadata>
	</package>

view raw example.nuspec hosted with ❤ by GitHub

To transform this nuspec file to a valid nuget package, use the following command:

nuget pack example.nuspec

Using a csproj file with dotnet pack

A second option is to put all the metadata inside your csproj file:

	<Project Sdk="Microsoft.NET.Sdk">
	<PropertyGroup>
	<TargetFramework>netstandard2.0</TargetFramework>
	<PackageId>Example</PackageId>
	<Version>1.0.0</Version>
	<Authors>Bart Wullems</Authors>
	<Description>Hello world</Description>
	</PropertyGroup>
	</Project>

view raw Example.csproj hosted with ❤ by GitHub

Now we can transform this to a valid nuget package, use the following command

dotnet pack example.csproj

Where was I wrong?

Both of the options above work, but first of all I though that these are the only options(my first mistake) and second I thought that these options were mutually exclusive(my second mistake).

My first mistake

Next to the 2 commands above you can also use msbuild directly:

# Uses the project file in the current folder by default
msbuild -t:pack 

You can trigger the same command by setting the following property inside your csproj file:

<GeneratePackageOnBuild>true</GeneratePackageOnBuild>

My second mistake

I also discovered that you can still use a nuspec file when using dotnet pack. Inside your csproj file you can point to the location of a nuspec file:

	<Project Sdk="Microsoft.NET.Sdk">
	<PropertyGroup>
	<TargetFramework>netstandard2.0</TargetFramework>
	<!-- 👇 Add this line -->
	<NuSpecFile>Example.nuspec</NuSpecFile>
	</PropertyGroup>
	</Project>

view raw Example.csproj hosted with ❤ by GitHub

More information

NuGet Command-Line Interface (CLI) Reference | Microsoft Learn

dotnet pack command - .NET CLI | Microsoft Learn