Version: 2020.3
Package Manifest window
Accessing package assets

Scripting API for packages

You can use the Package Manager scripting API to interact with the Package Manager using C# scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
See in Glossary
. For example, you might want to install a specific package or version depending on the platform of the target machine.

The system relies heavily on the PackageManager.Client class, which you can use to find packages, browse the list of packages, and install and uninstall packages through scripting.

Another important class is PackageManager.PackageInfo, which contains the state of a package, including metadata obtained from the package manifestEach package has a manifest, which provides information about the package to the Package Manager. The manifest contains information such as the name of the package, its version, a description for users, dependencies on other packages (if any), and other details. More info
See in Glossary
and the registry. For example, you can get a list of versions available for the package, or the list of any errors that might occur while locating or installing the package.

Adding a package to the project

This example demonstrates how to use the Client class to install or add a package to the project.

You can use Client.Add to add a package. When you call the Client.Add method, you can specify just the package name, or the name with a specific version. For example, using Client.Add("com.unity.textmeshpro") installs (or updates to) the latest version of the TextMesh Pro package; using Client.Add("com.unity.textmeshpro@1.3.0") installs version 1.3.0 of the TextMesh Pro package.

The Client.Add method returns an AddRequest instance, which you can use to get the status, any errors, or a Request response that contains the PackageInfo information for the newly added package.

using System;
using UnityEditor;
using UnityEditor.PackageManager.Requests;
using UnityEditor.PackageManager;
using UnityEngine;

namespace Unity.Editor.Example {
   static class AddPackageExample
   {
       static AddRequest Request;
      
       [MenuItem("Window/Add Package Example")]
       static void Add()
       {
           // Add a package to the project
           Request = Client.Add("com.unity.textmeshpro");
           EditorApplication.update += Progress;
       }

       static void Progress()
       {
           if (Request.IsCompleted)
           {
               if (Request.Status == StatusCode.Success)
                   Debug.Log("Installed: " + Request.Result.packageId);
               else if (Request.Status >= StatusCode.Failure)
                   Debug.Log(Request.Error.message);

               EditorApplication.update -= Progress;
           }
       }
   }
}

Browsing the list of packages in a project

This example demonstrates how to use the Client class to iterate over the packages in the project.

The Client.List method returns a ListRequest instance, which you can use to get the status of the List operation, any errors, or a Request response that contains the PackageCollection which you can iterate.

using System;
using UnityEditor;
using UnityEditor.PackageManager.Requests;
using UnityEditor.PackageManager;
using UnityEngine;

namespace Unity.Editor.Example {
   static class ListPackageExample
   {
       static ListRequest Request;
    
       [MenuItem("Window/List Package Example")]
       static void List()
       {
           Request = Client.List();    // List packages installed for the project
           EditorApplication.update += Progress;
       }

       static void Progress()
       {
           if (Request.IsCompleted)
           {
               if (Request.Status == StatusCode.Success)
                   foreach (var package in Request.Result)
                       Debug.Log("Package name: " + package.name);
               else if (Request.Status >= StatusCode.Failure)
                   Debug.Log(Request.Error.message);

               EditorApplication.update -= Progress;
           }
       }
   }
}

Embedding a package in the project

This example demonstrates how to use the Client class to embed one of the packages already installed in your project. The main method is the Client.Embed method, which makes a copy of the package and stores it under the Packages folder of your project.

The Client.Embed method returns an EmbedRequest instance, which you can use to get the status of the Embed operation, any errors, or a Request response that contains the PackageInfo information for the newly embedded package
See in Glossary
.

This example also uses the Client.List method to access the collection of packages currently installed in your project and picks out the first one that is neither embedded nor built-in.

The Client.List method returns a ListRequest instance, which you can use to get the status of the List operation, any errors, or a Request response that contains the PackageCollection which you can iterate.

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEditor.PackageManager.Requests;
using UnityEditor.PackageManager;
using UnityEngine;

namespace Unity.Editor.Example
{
    static class EmbedPackageExample
    {
        static String targetPackage;
        static EmbedRequest Request;
        static ListRequest LRequest;

        [MenuItem("Window/Embed Package Example")]
        static void GetPackageName()
        {
            // First get the name of an installed package
            LRequest = Client.List();
            EditorApplication.update += LProgress;
        }

        static void LProgress()
        {
            if (LRequest.IsCompleted)
            {
                if (LRequest.Status == StatusCode.Success)
                {
                    foreach (var package in LRequest.Result)
                    {
                        // Only retrieve packages that are currently installed in the
                        // project (and are neither Built-In nor already Embedded)
                        if (package.isDirectDependency && package.source
                            != PackageSource.BuiltIn && package.source
                            != PackageSource.Embedded)
                        {
                            targetPackage = package.name;
                            break;
                        }
                    }

                }
                else
                    Debug.Log(LRequest.Error.message);

                EditorApplication.update -= LProgress;

                Embed(targetPackage);

            }
        }

        static void Embed(string inTarget)
        {
            // Embed a package in the project
            Debug.Log("Embed('" + inTarget + "') called");
            Request = Client.Embed(inTarget);
            EditorApplication.update += Progress;

        }

        static void Progress()
        {
            if (Request.IsCompleted)
            {
                if (Request.Status == StatusCode.Success)
                    Debug.Log("Embedded: " + Request.Result.packageId);
                else if (Request.Status >= StatusCode.Failure)
                    Debug.Log(Request.Error.message);

                EditorApplication.update -= Progress;
            }
        }
    }
}


Package Manager events

Use the Events class to register an event handler with the Package Manager. The Events class contains two events you can subscribe to, which the Package Manager raises at these points:

  • Immediately before the Package Manager changes the list of dependenciesIn the context of the Package Manager, a dependency is a specific package version (expressed in the form package_name@package_version) that a project or another package requires in order to work. Projects and packages use the dependencies attribute in their manifests to define the set of packages they require. For projects, these are considered direct dependencies; for packages, these are indirect, or transitive, dependencies. More info
    See in Glossary
    (registeringPackages)
  • After the Package Manager imports and compiles the changed list of package dependencies (registeredPackages)

The following examples demonstrate how to use both of these events.

Example of using the registeringPackages event

using UnityEditor.PackageManager;
using UnityEngine;

namespace Unity.Editor.Example
{
    public class EventSubscribingExample_RegisteringPackages
    {
        public EventSubscribingExample_RegisteringPackages()
        {
            // Subscribe to the event using the addition assignment operator (+=).
            // This executes the code in the handler whenever the event is fired.
            Events.registeringPackages += RegisteringPackagesEventHandler;
        }

        // The method is expected to receive a PackageRegistrationEventArgs event argument.
        void RegisteringPackagesEventHandler(PackageRegistrationEventArgs packageRegistrationEventArgs)
        {
            Debug.Log("The list of registered packages is about to change!");

           foreach (var addedPackage in packageRegistrationEventArgs.added)
            {
                Debug.Log($"Adding {addedPackage.displayName}");
            }

            foreach (var removedPackage in packageRegistrationEventArgs.removed)
            {
                Debug.Log($"Removing {removedPackage.displayName}");
            }

            // The changedFrom and changedTo collections contain the packages that are about to be updated.
            // Both collections are guaranteed to be the same size with indices matching the same package name.
            for (int i = 0; i <= packageRegistrationEventArgs.changedFrom.Count; i++)
            {
                var oldPackage = packageRegistrationEventArgs.changedFrom[i];
                var newPackage = packageRegistrationEventArgs.changedTo[i];

                Debug.Log($"Changing ${oldPackage.displayName} version from ${oldPackage.version} to ${newPackage.version}");
            }
        }
    }
}

Example of using the registeredPackages event

using UnityEditor;
using UnityEditor.PackageManager;
using UnityEngine;

namespace Unity.Editor.Example
{
    public class EventSubscribingExample_RegisteredPackages
    {
        // You must use '[InitializeOnLoadMethod]' or '[InitializeOnLoad]' to subscribe to this event.
        [InitializeOnLoadMethod]
        static void SubscribeToEvent()
        {
            // This causes the method to be invoked after the Editor registers the new list of packages.
            Events.registeredPackages += RegisteredPackagesEventHandler;
        }

        static void RegisteredPackagesEventHandler(PackageRegistrationEventArgs packageRegistrationEventArgs)
        {
            // Code executed here can safely assume that the Editor has finished compiling the new list of packages
            Debug.Log("The list of registered packages has changed!");
        }
    }
}
Package Manifest window
Accessing package assets