Custom Loader Node script that uses TextAsset as source of assets to load

LoadByAssetList.cs

using UnityEngine;
using UnityEditor;

using System;
using System.Linq;
using System.IO;
using System.Collections.Generic;
using System.Text.RegularExpressions;

using UnityEngine.AssetBundles.GraphTool;
using Model=UnityEngine.AssetBundles.GraphTool.DataModel.Version2;

[CustomNode("LoadByAssetList", 11)]
public class LoadByAssetList : Node {

	[SerializeField] private TextAsset m_assetListText;

	private string m_lastLoadedText;
	private List<AssetReference> m_references;
	private Vector2 m_scroll;

	public override string ActiveStyle {
		get {
			return "flow node 0 on";
		}
	}

	public override string InactiveStyle {
		get {
			return "flow node 0";
		}
	}

	public override Model.NodeOutputSemantics NodeInputType {
		get {
			return Model.NodeOutputSemantics.None;
		}
	}

	public override void Initialize(Model.NodeData data) {
		data.AddDefaultOutputPoint();
	}

	public override Node Clone() {
		var newNode = new LoadByAssetList();
		newNode.m_assetListText = m_assetListText;

		return newNode;
	}
		
	public override void OnInspectorGUI(NodeGUI node, AssetReferenceStreamManager streamManager, NodeGUIEditor editor, Action onValueChanged) {

		EditorGUILayout.HelpBox("LoadByAssetList: Load assets from given list of asssets defined in assigned TextAsset", MessageType.Info);
		editor.UpdateNodeName(node);

		GUILayout.Space(10f);

		using (new EditorGUILayout.VerticalScope(GUI.skin.box)) {
			var newText = EditorGUILayout.ObjectField("Asset Paths", m_assetListText, typeof(TextAsset), false) as TextAsset;
			if(newText != m_assetListText) {
				using(new RecordUndoScope("Change Text Asset", node, true)) {
					m_assetListText = newText;
					m_references = null;
					onValueChanged();
				}
			}
		}

		GUILayout.Space(20f);

		if(m_lastLoadedText != null) {
			GUILayout.Label("Loaded text", "BoldLabel");
			using(var scrollScope = new EditorGUILayout.ScrollViewScope(m_scroll) ) {
				m_scroll = scrollScope.scrollPosition;

				GUILayout.TextArea(m_lastLoadedText);
			}
		}
	}


	public override void Prepare (BuildTarget target, 
		Model.NodeData node, 
		IEnumerable<PerformGraph.AssetGroups> incoming, 
		IEnumerable<Model.ConnectionData> connectionsToOutput, 
		PerformGraph.Output Output) 
	{
		ValidateTextAssetPaths(
			m_assetListText,
			() => {
				throw new NodeException(node.Name + ": Text Asset is not assigned.", node.Id);
			}
		);

		ParseTextAndRefreshReferences(node);
		Load(connectionsToOutput, Output);
	}

	private void ParseTextAndRefreshReferences(Model.NodeData node) {

		var curText= m_assetListText.text;

		if(m_lastLoadedText == curText) {
			return;
		}

		var newReferences = new List<AssetReference>();

		char[] splitters = new char[] {'\r','\n'};
		var paths = curText.Split(splitters); 

		foreach(var p in paths) {

			var path = p.Trim();
			if(string.IsNullOrEmpty(path)) {
				continue;
			}

			// handle comments
			if(path[0] == '#') {
				continue;
			}

			var guid = AssetDatabase.AssetPathToGUID(path);
			if(guid == null) {
				throw new NodeException(node.Name + ": Asset not found. Please fix issue in TextAsset: " + path, node.Id);
			}

			var r = AssetReferenceDatabase.GetReference(path);
			if(r == null) {
				throw new NodeException(node.Name + ": Failed to acquire asset reference(Did you set wrong path?). Please fix issue in TextAsset: " + path, node.Id);
			}
			newReferences.Add(r);
		}

		m_references = newReferences;
		m_lastLoadedText = curText;
	}

	void Load ( IEnumerable<Model.ConnectionData> connectionsToOutput, PerformGraph.Output Output) 
	{

		if(connectionsToOutput == null || Output == null) {
			return;
		}

		var output = new Dictionary<string, List<AssetReference>> {
			{"0", m_references}
		};

		var dst = (connectionsToOutput == null || !connectionsToOutput.Any())? 
			null : connectionsToOutput.First();
		Output(dst, output);
	}

	public static void ValidateTextAssetPaths (TextAsset textAsset, Action NullOrEmpty) {
		if (textAsset == null) NullOrEmpty();
	}
}