====== 5.2 NuGet Basics ======

This page explains what NuGet is and how to create packages for native libraries.

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===== What is NuGet? =====

**NuGet** is the package manager for .NET - comparable to:
  * npm for JavaScript
  * pip for Python
  * Maven for Java

A NuGet package (''.nupkg'') contains:
  * Compiled DLLs
  * Metadata (name, version, author)
  * Native libraries (optional)

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===== Why a NuGet Package? =====

| Without NuGet | With NuGet |
|---------------|------------|
| Copy DLLs manually | ''dotnet add package ...'' |
| Manage versions manually | Automatic updates |
| Each project separately | Central repository |

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===== Package Structure for Native Libraries =====

NuGet supports native DLLs via ''runtimes/'':

<code>
MyPackage.1.0.0.nupkg/
├── lib/
│   └── net8.0/
│       └── MyPackage.dll        # .NET Wrapper
├── runtimes/
│   ├── win-x64/
│   │   └── native/
│   │       ├── libcrypto-3-x64.dll
│   │       └── libssl-3-x64.dll
│   └── linux-x64/
│       └── native/
│           ├── libcrypto.so.3
│           └── libssl.so.3
└── MyPackage.nuspec
</code>

----

===== Simple .nuspec Example =====

Create a file ''OpenSsl.Native.nuspec'':

<code xml>
<?xml version="1.0"?>
<package>
  <metadata>
    <id>OpenSsl.Native</id>
    <version>3.6.0</version>
    <authors>Your Name</authors>
    <description>OpenSSL 3.6.0 Native Libraries with Post-Quantum Support</description>
    <tags>openssl cryptography post-quantum ml-dsa ml-kem</tags>
  </metadata>
  <files>
    <!-- Windows x64 -->
    <file src="win-x64\libcrypto-3-x64.dll" target="runtimes\win-x64\native\" />
    <file src="win-x64\libssl-3-x64.dll" target="runtimes\win-x64\native\" />

    <!-- Linux x64 -->
    <file src="linux-x64\libcrypto.so.3" target="runtimes\linux-x64\native\" />
    <file src="linux-x64\libssl.so.3" target="runtimes\linux-x64\native\" />
  </files>
</package>
</code>

----

===== Create Package =====

==== 1. Prepare Files ====

<code powershell>
# Create directory structure
mkdir nuget-package
mkdir nuget-package\win-x64
mkdir nuget-package\linux-x64

# Copy DLLs
copy "D:\Projects\openssl-3.6.0\bin\bin\libcrypto-3-x64.dll" nuget-package\win-x64\
copy "D:\Projects\openssl-3.6.0\bin\bin\libssl-3-x64.dll" nuget-package\win-x64\

# Create .nuspec (see above)
</code>

==== 2. Build Package ====

<code powershell>
cd nuget-package

# Install NuGet CLI (if not present)
winget install Microsoft.NuGet

# Create package
nuget pack OpenSsl.Native.nuspec

# Result: OpenSsl.Native.3.6.0.nupkg
</code>

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===== Local NuGet Feed =====

For internal use you can set up a local NuGet feed:

==== 1. Create Feed Folder ====

<code powershell>
mkdir C:\NuGetFeed
copy OpenSsl.Native.3.6.0.nupkg C:\NuGetFeed\
</code>

==== 2. Register Feed in NuGet.config ====

Create ''NuGet.config'' in project folder:

<code xml>
<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
    <add key="LocalFeed" value="C:\NuGetFeed" />
  </packageSources>
</configuration>
</code>

==== 3. Use Package ====

<code powershell>
dotnet add package OpenSsl.Native --version 3.6.0 --source C:\NuGetFeed
</code>

----

===== With .NET SDK Pack =====

Alternatively you can pack directly from .csproj:

<code xml>
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <PackageId>OpenSsl.Native</PackageId>
    <Version>3.6.0</Version>
    <Authors>Your Name</Authors>
    <Description>OpenSSL 3.6.0 Native Libraries</Description>
    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
  </PropertyGroup>

  <ItemGroup>
    <None Include="runtimes\**\*" Pack="true" PackagePath="runtimes\" />
  </ItemGroup>
</Project>
</code>

Then:
<code powershell>
dotnet pack -c Release
</code>

----

===== Network Feed Setup =====

For teams: Feed on network drive

==== Server Side ====

<code powershell>
# Create share (as Admin)
New-SmbShare -Name "NuGetFeed" -Path "D:\NuGetFeed" -ReadAccess "Everyone"
</code>

==== Client Side ====

<code xml>
<!-- NuGet.config -->
<configuration>
  <packageSources>
    <add key="InternalFeed" value="\\server\NuGetFeed" />
  </packageSources>
</configuration>
</code>

----

===== Tips =====

<WRAP tip>
**Versioning:**
  * Semantic Versioning: ''MAJOR.MINOR.PATCH''
  * OpenSSL 3.6.0 → Package 3.6.0
  * Own fixes → 3.6.0.1, 3.6.0.2
</WRAP>

<WRAP important>
**No secrets in packages!**

  * No API keys
  * No private keys
  * No passwords in configurations
</WRAP>

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===== Continue to =====

  * [[.:verteilung:nuget-paket|Publish NuGet Package]]
  * [[.:verteilung:start|6. Distribution]]

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//Wolfgang van der Stille @ EMSR DATA d.o.o. - Post-Quantum Cryptography Professional//