.nuspec reference

A .nuspec file is an XML manifest that contains package metadata. This manifest is used both to build the package and to provide information to consumers. The manifest is always included in a package.

In this topic:

General form and schema

The current nuspec.xsd schema file can be found in the NuGet GitHub repository.

Within this schema, a .nuspec file has the following general form:

<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
        <!-- Required elements-->
        <id></id>
        <version></version>
        <description></description>
        <authors></authors>

        <!-- Optional elements -->
        <!-- ... -->
    </metadata>
    <!-- Optional 'files' node -->
</package>

For a clear visual representation of the schema, open the schema file in Visual Studio in Design mode and click on the XML Schema Explorer link. Alternately, open the file as code, right-click in the editor, and select Show XML Schema Explorer. Either way you get a view like the one below (when mostly expanded):

Visual Studio Schema Explorer with nuspec.xsd open

Required metadata elements

Although the following elements are the minimum requirements for a package, you should consider adding the optional metadata elements to improve the overall experience developers have with your package.

These elements must appear within a <metadata> element.

Element Description
id The case-insensitive package identifier, which must be unique across nuget.org or whatever gallery the package resides in. IDs may not contain spaces or characters that are not valid for a URL, and generally follow .NET namespace rules. See Choosing a unique package identifier for guidance.
version The version of the package, following the major.minor.patch pattern. Version numbers may include a pre-release suffix as described in Package versioning.
description A long description of the package for UI display.
authors A comma-separated list of packages authors, matching the profile names on nuget.org. These are displayed in the NuGet Gallery on nuget.org and are used to cross-reference packages by the same authors.

Optional metadata elements

These elements must appear within a <metadata> element.

Single elements

Element Description
title A human-friendly title of the package, typically used in UI displays as on nuget.org and the Package Manager in Visual Studio. If not specified, the package ID is used.
owners A comma-separated list of the package creators using profile names on nuget.org. This is often the same list as in authors, and is ignored when uploading the package to nuget.org. See Managing package owners on nuget.org.
projectUrl A URL for the package's home page, often shown in UI displays as well as nuget.org.
licenseUrl A URL for the package's license, often shown in UI displays as well as nuget.org.
iconUrl A URL for a 64x64 image with transparency background to use as the icon for the package in UI display. Be sure this element contains the direct image URL and not the URL of a web page containing the image. For example, to use an image from GitHub, use the raw file URL like https://github.com/<username\>/<repsitory>/raw/<branch>/<logo.png>.
requireLicenseAcceptance A Boolean value specifying whether the client must prompt the consumer to accept the package license before installing the package.
developmentDependency (2.8+) A Boolean value specifying whether the package is be marked as a development-only-dependency, which prevents the package from being included as a dependency in other packages.
summary A short description of the package for UI display. If omitted, a truncated version of description is used.
releaseNotes (1.5+) A description of the changes made in this release of the package, often used in UI like the Updates tab of the Visual Studio Package Manager in place of the package description.
copyright (1.5+) Copyright details for the package.
language The locale ID for the package. See Creating localized packages.
tags A space-delimited list of tags and keywords that describe the package and aid discoverability of packages through search and filtering.
serviceable (3.3+)For internal NuGet use only.
minClientVersion (2.5+) Specifies the minimum version of the NuGet client that can install this package, enforced by nuget.exe and the Visual Studio Package Manager. This is used whenever the package depends on specific features of the .nuspec file that were added in a particular version of the NuGet client. For example, a package using the developmentDependency attribute should specify "2.8" for minClientVersion. Similarly, a package using the contentFiles element (see the next section) should set minClientVersion to "3.3". Note also that because NuGet clients prior to 2.5 do not recognize this flag, they always refuse to install the package no matter what minClientVersion contains.

Collection elements

Element Description
packageTypes (3.3+) A collection of zero or more <packageType> elements specifying the type of the package if other than a traditional dependency package. Each packageType has attributes of name and version. See Setting a package type.
dependencies A collection of zero or more <dependency> elements specifying the dependencies for the package. Each dependency has attributes of id, version, include (3.x+), and exclude (3.x+). See Dependencies below.
frameworkAssemblies (1.2+) A collection of zero or more <frameworkAssembly> elements identifying .NET Framework assembly references that this package requires, which ensures that references are added to projects consuming the package. Each frameworkAssembly has assemblyName and targetFramework attributes. See Specifying framework assembly references GAC below.
references (1.5+) A collection of zero or more <reference> elements naming assemblies in the package's lib folder that are added as project references. Each reference has a file attribute. <references> can also contain a <group> element with a targetFramework attribute, that then contains <reference> elements. If omitted, all references in lib are included. See Specifying explicit assembly references below.
contentFiles (3.3+) A collection of <files> elements that identify content files to include in the consuming project. These files are specified with a set of attributes that describe how they should be used within the project system. See Specifying files to include in the package below.

Files element

The <package> node may contain a <files> or <contentFiles> node as siblings to <metadata> to specify which assembly and content files to include in the package. See Including assembly files and Including content files later in this topic for details.

Replacement tokens

When creating a package, the nuget pack command replaces $-delimited tokens in the .nuspec file's <metadata> node with values that come from either a project file or the pack command's -properties switch.

On the command line, you specify token values with nuget pack -properties <name>=<value>;<name>=<value>. For example, you can use a token such as $owners$ and $desc$ in the .nuspec and provide the values at packing time as follows:

nuget pack MyProject.csproj -properties
    owners=janedoe,harikm,kimo,xiaop;desc="Awesome app logger utility"

To use values from a project, specify the tokens described in the table below (AssemblyInfo refers to the file in Properties such as AssemblyInfo.cs or AssemblyInfo.vb).

To use these tokens, run nuget pack with the project file rather than just the .nuspec. For example, when using the following command, the $id$ and $version$ tokens in a .nuspec file are replaced with the project's AssemblyName and AssemblyVersion values:

nuget pack MyProject.csproj

Typically, when you have a project, you create the .nuspec initially using nuget spec MyProject.csproj which automatically includes some of these standard tokens. However, if a project lacks values for required .nuspec elements, then nuget pack fails. Furthermore, if you change project values, be sure to rebuild before creating the package; this can be done conveniently with the pack command's build switch.

With the exception of $configuration$, values in the project are used in preference to any assigned to the same token on the command line.

Token Value source Value
$id$ Project file AssemblyName from the project file
$version$ AssemblyInfo AssemblyInformationalVersion if present, otherwise AssemblyVersion
$author$ AssemblyInfo AssemblyCompany
$description$ AssemblyInfo AssemblyDescription
$copyright$ AssemblyInfo AssemblyCopyright
$configuration$ Assembly DLL Configuration used to build the assembly, defaulting to Debug. Note that to create a package using a Release configuration, you always use -properties Configuration=Release on the command line.

Tokens can also be used to resolve paths when you include assembly files and content files. The tokens have the same names as the MSBuild properties, making it possible to select files to be included depending on the current build configuration. For example, if you use the following tokens in the .nuspec file:

<files>
    <file src="bin\$configuration$\$id$.pdb" target="lib\net40\" />
</files>

And you build an assembly whose AssemblyName is LoggingLibrary with the Release configuration in MSBuild, the resulting lines in the .nuspec file in the package is as follows:

<files>
    <file src="bin\Release\LoggingLibrary.pdb" target="lib\net40" />
</files>

Dependencies

The <dependencies> element within <metadata> contains any number of <dependency> elements that identify other packages upon which the top-level package depends. The attributes for each <dependency> are as follows:

Attribute Description
id (Required) The package ID of the dependency.
version (Required) The range of versions acceptable as a dependency. See Package versioning for exact syntax.

For example, the following lines indicate dependencies on PackageA version 1.1.0 or higher, and PackageB version 1.x.

<dependencies>
    <dependency id="PackageA" version="1.1.0" />
    <dependency id="PackageB" version="[1,2)" />
</dependencies>

When creating a .nuspec from a project using nuget spec, dependencies that exist in that project are automatically included in the resulting .nuspec file.

Dependency groups

Version 2.0+

As an alternative to a single flat list, dependencies can be specified according to the framework profile of the target project using <group> elements within <dependencies>.

Each group has an attribute named targetFramework and contains zero or more <dependency> elements. Those dependencies are installed together when the target framework is compatible with the project's framework profile.

The <group> element without a targetFramework attribute is used as the default or fallback list of dependencies. See Target frameworks for the exact framework identifiers.

Important

The group format cannot be intermixed with a flat list.

The following example shows different variations of the <group> element:

<dependencies>
    <group>
        <dependency id="RouteMagic" version="1.1.0" />
    </group>

    <group targetFramework="net40">
        <dependency id="jQuery" />
        <dependency id="WebActivator" />
    </group>

    <group targetFramework="sl30">
    </group>
</dependencies>

Explicit assembly references

The <references> element explicitly specifies the assemblies that the target project should reference when using the package. When this element is present, NuGet add references to only the listed assemblies; it does not add references for any other assemblies in the package's lib folder.

For example, the following <references> element instructs NuGet to add references to only xunit.dll and xunit.extensions.dll even if there are additional assemblies in the package:

<references>
    <reference file="xunit.dll" />
    <reference file="xunit.extensions.dll" />
</references>

Explicit references are typically used for design-time only assemblies. When using Code Contracts, for example, contract assemblies need to be next to the runtime assemblies that they augment so that Visual Studio can find them, but the contract assemblies need not be referenced by the project or copied into the project's bin folder.

Similarly, explicit references can be used for unit test frameworks, such as XUnit, which needs its tools assemblies located next to the runtime assemblies, but does not need them included as project references.

Reference groups

Version 2.5+

As an alternative to a single flat list, references can be specified according to the framework profile of the target project using <group> elements within <references>.

Each group has an attribute named targetFramework and contains zero or more <reference> elements. Those references are added to a project when the target framework is compatible with the project's framework profile.

The <group> element without a targetFramework attribute is used as the default or fallback list of references. See Target frameworks for the exact framework identifiers.

Important

The group format cannot be intermixed with a flat list.

The following example shows different variations of the <group> element:

<references>
    <group>
    <reference file="a.dll" />
    </group>

    <group targetFramework="net45">
        <reference file="b45.dll" />
    </group>

    <group targetFramework="netcore45">
    <reference file="bcore45.dll" />
    </group>
</references>

Framework assembly references

Framework assemblies are those that are part of the .NET framework and should already be in the global assembly cache (GAC) for any given machine. By identifying those assemblies within the <frameworkAssemblies> element, a package can ensure that required references are added to a project in the event that the project doesn't have such references already. Such assemblies, of course, are not included in a package directly.

The <frameworkAssemblies> element contains zero or more <frameworkAssembly> elements, each of which specifies the following attributes:

Attribute Description
assemblyName (Required) The fully qualified assembly name.
targetFramework (Optional) Specifies the target framework to which this reference applies. If omitted, indicates that the reference applies to all frameworks. See Target frameworks for the exact framework identifiers.

The following example shows a reference to System.Net for all target frameworks, and a reference to System.ServiceModel for .NET Framework 4.0 only:

<frameworkAssemblies>
    <frameworkAssembly assemblyName="System.Net"  />

    <frameworkAssembly assemblyName="System.ServiceModel" targetFramework="net40" />
</frameworkAssemblies>

Including assembly files

If you follow the conventions described in Creating a Package, you do not have to explicitly specify a list of files in the .nuspec file. The nuget pack command automatically picks up the necessary files.

Important

When a package is installed into a project, NuGet automatically adds assembly references to the package's DLLs, excluding those that are named .resources.dll because they are assumed to be localized satellite assemblies. For this reason, avoid using .resources.dll for files that otherwise contain essential package code.

To bypass this automatic behavior and explicitly control which files are included in a package, place a <files> element as a child of <package> (and a sibling of <metadata>), identifying each file with a separate <file> element. For example:

<files>
    <file src="bin\Debug\*.dll" target="lib" />
    <file src="bin\Debug\*.pdb" target="lib" />
    <file src="tools\**\*.*" exclude="**\*.log" />
</files>

With NuGet 2.x and earlier, and projects using packages.config, the <files> element is also used to include immutable content files when a package is installed. With NuGet 3.3+ and projects using project.json pr PackageReference, the <contentFiles> element is used instead. See Including content files below for details.

File element attributes

Each <file> element specifies the following attributes:

Attribute Description
src The location of the file or files to include, subject to exclusions specified by the exclude attribute. The path is relative to the .nuspec file unless an absolute path is specified. The wildcard character * is allowed, and the double wildcard ** implies a recursive folder search.
target The relative path to the folder within the package where the source files are placed, which must begin with lib, content, build, or tools. See Creating a .nuspec from a convention-based working directory.
exclude A semicolon-delimited list of files or file patterns to exclude from the src location. The wildcard character * is allowed, and the double wildcard ** implies a recursive folder search.

Examples

Single assembly

Source file:
    library.dll

.nuspec entry:
    <file src="library.dll" target="lib" />

Packaged result:
    lib\library.dll

Single assembly specific to a target framework

Source file:
    library.dll

.nuspec entry:
    <file src="assemblies\net40\library.dll" target="lib\net40" />

Packaged result:
    lib\net40\library.dll

Set of DLLs using a wildcard

Source files:
    bin\release\libraryA.dll
    bin\release\libraryB.dll

.nuspec entry:
    <file src="bin\release\*.dll" target="lib" />

Packaged result:
    lib\libraryA.dll
    lib\libraryB.dll

DLLs for different frameworks

Source files:
    lib\net40\library.dll
    lib\net20\library.dll

.nuspec entry (using ** recursive search):
    <file src="lib\**" target="lib" />

Packaged result:
    lib\net40\library.dll
    lib\net20\library.dll

Excluding files

Source files:
    \tools\*.bak
    \tools\*.log
    \tools\build\*.log

.nuspec entries:
    <file src="tools\*.*" target="tools" exclude="tools\*.bak" />
    <file src="tools\**\*.*" target="tools" exclude="**\*.log" />

Package result:
    (no files)

Including content files

Content files are immutable files that a package needs to include in a project. Being immutable, they are not intended to be modified by the consuming project. Example content files include:

  • Images that are embedded as resources
  • Source files that are already compiled
  • Scripts that need to be included with the build output of the project
  • Configuration files for the package that need to be included in the project but don't need any project-specific changes

Content files are included in a package using the <files> element, specifying the content folder in the target attribute. However, such files are ignored when the package is installed in a project using the project.json system in NuGet 3.3+ or PackageReference in NuGet 4+, which instead uses the <contentFiles> element.

For maximum compatibility with consuming projects, a package ideally specifies the content files in both elements.

Using the files element for content files

For content files, simply use the same format as for assembly files, but specify content as the base folder in the target attribute as shown in the following examples.

Basic content files

Source files:
    css\mobile\style1.css
    css\mobile\style2.css

.nuspec entry:
    <file src="css\mobile\*.css" target="content\css\mobile" />

Packaged result:
    content\css\mobile\style1.css
    content\css\mobile\style2.css

Content files with directory structure

Source files:
    css\mobile\style.css
    css\mobile\wp7\style.css
    css\browser\style.css

.nuspec entry:
    <file src="css\**\*.css" target="content\css" />

Packaged result:
    content\css\mobile\style.css
    content\css\mobile\wp7\style.css
    content\css\browser\style.css

Content file specific to a target framework

Source file:
    css\cool\style.css

.nuspec entry
    <file src="css\cool\style.css" target="Content" />

Packaged result:
    content\style.css

Content file copied to a folder with dot in name

In this case, NuGet sees that the extension in target does not match the extension in src and thus treats that part of the name in target as a folder:

Source file:
    images\picture.png

.nuspec entry:
    <file src="images\picture.png" target="Content\images\package.icons" />

Packaged result:
    content\images\package.icons\picture.png

Content files without extensions

To include files without an extension, use the * or ** wildcards:

Source file:
    flags\installed

.nuspec entry:
    <file src="flags\**" target="flags" />

Packaged result:
    flags\installed

Content files with deep path and deep target

In this case, because the file extensions of the source and target match, NuGet assumes that the target is a file name and not a folder:

Source file:
    css\cool\style.css

.nuspec entry:
    <file src="css\cool\style.css" target="Content\css\cool" />
    or:
    <file src="css\cool\style.css" target="Content\css\cool\style.css" />

Packaged result:
    content\css\cool\style.css

Renaming a content file in the package

Source file:
    ie\css\style.css

.nuspec entry:
    <file src="ie\css\style.css" target="Content\css\ie.css" />

Packaged result:
    content\css\ie.css

Excluding files

Source file:
    docs\*.txt (multiple files)

.nuspec entry:
    <file src="docs\*.txt" target="content\docs" exclude="docs\admin.txt" />
    or
    <file src="*.txt" target="content\docs" exclude="admin.txt;log.txt" />

Packaged result:
    All .txt files from docs except admin.txt (first example)
    All .txt files from docs except admin.txt and log.txt (second example)

Using the contentFiles element for content files

Version 3.3+ with project.json and 4.0+ with PackageReference

By default, a package places content in a contentFiles folder (see below) and nuget pack included all files in that folder using default attributes. In this case it's not necessary to include a contentFiles node in the .nuspec at all.

To control which files are included, the <contentFiles> element specifies is a collection of <files> elements that identify the exact files include.

These files are specified with a set of attributes that describe how they should be used within the project system:

Attribute Description
include (Required) The location of the file or files to include, subject to exclusions specified by the exclude attribute. The path is relative to the .nuspec file unless an absolute path is specified. The wildcard character * is allowed, and the double wildcard ** implies a recursive folder search.
exclude A semicolon-delimited list of files or file patterns to exclude from the src location. The wildcard character * is allowed, and the double wildcard ** implies a recursive folder search.
buildAction The build action to assign to the content item for MSBuild, such as Content, None, Embedded Resource, Compile, etc. The default is Compile.
copyToOutput A Boolean indicating whether to copy content items to the build output folder. The default is false.
flatten A Boolean indicating whether to copy content items to a single folder in the build output (true), or to preserve the folder structure in the package (false). The default is false.

When installing a package, NuGet applies the child elements of <contentFiles> from top to bottom. If multiple entries match the same file then all entries are applied. The top-most entry overrides the lower entries if there is a conflict for the same attribute.

Package folder structure

The package project should structure content using the following pattern:

/contentFiles/{codeLanguage}/{TxM}/{any?}
  • codeLanguages may be cs, vb, fs, any, or the lowercase equivalent of a given $(ProjectLanguage)
  • TxM is any legal target framework moniker that NuGet supports (see Target frameworks).
  • Any folder structure may be appended to the end of this syntax.

For example:

Language- and framework-agnostic:
    /contentFiles/any/any/config.xml

net45 content for all languages
    /contentFiles/any/net45/config.xml

C#-specific content for net45 and up
    /contentFiles/cs/net45/sample.cs

Empty folders can use . to opt out of providing content for certain combinations of language and TxM, for example:

/contentFiles/vb/any/code.vb
/contentFiles/cs/any/.

Example contentFiles section

<contentFiles>
    <!-- Embed image resources -->
    <files include="any/any/images/dnf.png" buildAction="EmbeddedResource" />
    <files include="any/any/images/ui.png" buildAction="EmbeddedResource" />

    <!-- Embed all image resources under contentFiles/cs/ -->
    <files include="cs/**/*.png" buildAction="EmbeddedResource" />

    <!-- Copy config.xml to the root of the output folder -->
    <files include="cs/uap/config/config.xml" buildAction="None" copyToOutput="true" flatten="true" />

    <!-- Copy run.cmd to the output folder and keep the directory structure -->
    <files include="cs/commands/run.cmd" buildAction="None" copyToOutput="true" flatten="false" />

    <!-- Include everything in the scripts folder except exe files -->
    <files include="cs/net45/scripts/*" exclude="**/*.exe"  buildAction="None" copyToOutput="true" />
</contentFiles>

Example .nuspec files

A simple .nuspec that does not specify dependencies or files

<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
    <id>sample</id>
    <version>1.2.3</version>
    <authors>Kim Abercrombie, Franck Halmaert</authors>
    <description>Sample exists only to show a sample .nuspec file.</description>
    <language>en-US</language>
    <projectUrl>http://xunit.codeplex.com/</projectUrl>
    <licenseUrl>http://xunit.codeplex.com/license</licenseUrl>
    </metadata>
</package>

A .nuspec with dependencies

<?xml version="1.0" encoding="utf-8"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
    <id>sample</id>
    <version>1.0.0</version>
    <authors>Microsoft</authors>
    <dependencies>
        <dependency id="another-package" version="3.0.0" />
        <dependency id="yet-another-package" version="1.0.0" />
    </dependencies>
    </metadata>
</package>

A .nuspec with files

<?xml version="1.0"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
    <id>routedebugger</id>
    <version>1.0.0</version>
    <authors>Jay Hamlin</authors>
    <requireLicenseAcceptance>false</requireLicenseAcceptance>
    <description>Route Debugger is a little utility I wrote...</description>
    </metadata>
    <files>
    <file src="bin\Debug\*.dll" target="lib" />
    </files>
</package>

A .nuspec with framework assemblies

<?xml version="1.0"?>
<package xmlns="http://schemas.microsoft.com/packaging/2010/07/nuspec.xsd">
    <metadata>
    <id>PackageWithGacReferences</id>
    <version>1.0</version>
    <authors>Author here</authors>
    <requireLicenseAcceptance>false</requireLicenseAcceptance>
    <description>
        A package that has framework assemblyReferences depending
        on the target framework.
    </description>
    <frameworkAssemblies>
        <frameworkAssembly assemblyName="System.Web" targetFramework="net40" />
        <frameworkAssembly assemblyName="System.Net" targetFramework="net40-client, net40" />
        <frameworkAssembly assemblyName="Microsoft.Devices.Sensors" targetFramework="sl4-wp" />
        <frameworkAssembly assemblyName="System.Json" targetFramework="sl3" />
    </frameworkAssemblies>
    </metadata>
</package>

In this example, the following are installed for specific project targets:

  • .NET4 -> System.Web, System.Net
  • .NET4 Client Profile -> System.Net
  • Silverlight 3 -> System.Json
  • Silverlight 4 -> System.Windows.Controls.DomainServices
  • WindowsPhone -> Microsoft.Devices.Sensors