n8n/packages/workflow/src/WorkflowDataProxy.ts

import {
	IDataObject,
	INodeExecutionData,
	IRunExecutionData,
	IWorkflowDataProxyData,
	NodeHelpers,
	Workflow,
} from './';



export class WorkflowDataProxy {
	private workflow: Workflow;
	private runExecutionData: IRunExecutionData | null;
	private defaultReturnRunIndex: number;
	private runIndex: number;
	private itemIndex: number;
	private activeNodeName: string;
	private connectionInputData: INodeExecutionData[];



	constructor(workflow: Workflow, runExecutionData: IRunExecutionData | null, runIndex: number, itemIndex: number, activeNodeName: string, connectionInputData: INodeExecutionData[], defaultReturnRunIndex = -1) {
		this.workflow = workflow;
		this.runExecutionData = runExecutionData;
		this.defaultReturnRunIndex = defaultReturnRunIndex;
		this.runIndex = runIndex;
		this.itemIndex = itemIndex;
		this.activeNodeName = activeNodeName;
		this.connectionInputData = connectionInputData;
	}



	/**
	 * Returns a proxy which allows to query context data of a given node
	 *
	 * @private
	 * @param {string} nodeName The name of the node to get the context from
	 * @returns
	 * @memberof WorkflowDataProxy
	 */
	private nodeContextGetter(nodeName: string) {
		const that = this;
		const node = this.workflow.nodes[nodeName];

		return new Proxy({}, {
			ownKeys(target) {
				if (Reflect.ownKeys(target).length === 0) {
					// Target object did not get set yet
					Object.assign(target, NodeHelpers.getContext(that.runExecutionData!, 'node', node));
				}

				return Reflect.ownKeys(target);
			},
			get(target, name, receiver) {
				name = name.toString();
				const contextData = NodeHelpers.getContext(that.runExecutionData!, 'node', node);

				if (!contextData.hasOwnProperty(name)) {
					// Parameter does not exist on node
					throw new Error(`Could not find parameter "${name}" on context of node "${nodeName}"`);
				}

				return contextData[name];
			}
		});
	}



	/**
	 * Returns a proxy which allows to query parameter data of a given node
	 *
	 * @private
	 * @param {string} nodeName The name of the node to query data from
	 * @returns
	 * @memberof WorkflowDataGetter
	 */
	private nodeParameterGetter(nodeName: string) {
		const that = this;
		const node = this.workflow.nodes[nodeName];

		return new Proxy(node.parameters, {
			ownKeys(target) {
				return Reflect.ownKeys(target);
			},
			get(target, name, receiver) {
				name = name.toString();

				if (!node.parameters.hasOwnProperty(name)) {
					// Parameter does not exist on node
					throw new Error(`Could not find parameter "${name}" on node "${nodeName}"`);
				}

				const returnValue = node.parameters[name];

				if (typeof returnValue === 'string' && returnValue.charAt(0) === '=') {
					// The found value is an expression so resolve it
					return that.workflow.getParameterValue(returnValue, that.runExecutionData, that.runIndex, that.itemIndex, that.activeNodeName, that.connectionInputData);
				}

				return returnValue;
			}
		});
	}


	/**
	 * Returns the node ExecutionData
	 *
	 * @private
	 * @param {string} nodeName The name of the node query data from
	 * @param {boolean} [shortSyntax=false] If short syntax got used
	 * @param {number} [outputIndex] The index of the output, if not given the first one gets used
	 * @param {number} [runIndex] The index of the run, if not given the current one does get used
	 * @returns {INodeExecutionData[]}
	 * @memberof WorkflowDataProxy
	 */
	private getNodeExecutionData(nodeName: string, shortSyntax = false, outputIndex?: number, runIndex?: number): INodeExecutionData[] {
		const that = this;

		let executionData: INodeExecutionData[];
		if (shortSyntax === false) {
			// Long syntax got used to return data from node in path

			if (that.runExecutionData === null) {
				throw new Error(`Workflow did not run so do not have any execution-data.`);
			}

			if (!that.runExecutionData.resultData.runData.hasOwnProperty(nodeName)) {
				throw new Error(`No execution data found for node "${nodeName}"`);
			}

			runIndex = runIndex === undefined ? that.defaultReturnRunIndex : runIndex;
			runIndex = runIndex === -1 ? (that.runExecutionData.resultData.runData[nodeName].length -1) : runIndex;

			if (that.runExecutionData.resultData.runData[nodeName].length < runIndex) {
				throw new Error(`No execution data found for run "${runIndex}" of node "${nodeName}"`);
			}

			const taskData = that.runExecutionData.resultData.runData[nodeName][runIndex].data!;

			if (taskData.main === null || !taskData.main.length || taskData.main[0] === null) {
				// throw new Error(`No data found for item-index: "${itemIndex}"`);
				throw new Error(`No data found from "main" input.`);
			}

			// Check from which output to read the data.
			// Depends on how the nodes are connected.
			// (example "IF" node. If node is connected to "true" or to "false" output)
			if (outputIndex === undefined) {
				const outputIndex = that.workflow.getNodeConnectionOutputIndex(that.activeNodeName, nodeName, 'main');

				if (outputIndex === undefined) {
					throw new Error(`The node "${that.activeNodeName}" is not connected with node "${nodeName}" so no data can get returned from it.`);
				}
			}

			if (outputIndex === undefined) {
				outputIndex = 0;
			}

			if (taskData.main.length < outputIndex) {
				throw new Error(`No data found from "main" input with index "${outputIndex}" via which node is connected with.`);
			}

			executionData = taskData.main[outputIndex] as INodeExecutionData[];
		} else {
			// Short syntax got used to return data from active node

			// TODO: Here have to generate connection Input data for the current node by itself
			// Data needed:
			// #- the run-index
			// - node which did send data (has to be the one from last recent execution)
			// - later also the name of the input and its index (currently not needed as it is always "main" and index "0")
			executionData = that.connectionInputData;
		}

		return executionData;
	}


	/**
	 * Returns a proxy which allows to query data of a given node
	 *
	 * @private
	 * @param {string} nodeName The name of the node query data from
	 * @param {boolean} [shortSyntax=false] If short syntax got used
	 * @returns
	 * @memberof WorkflowDataGetter
	 */
	private nodeDataGetter(nodeName: string, shortSyntax = false) {

		const that = this;
		const node = this.workflow.nodes[nodeName];

		if (!node) {
			throw new Error(`The node "${nodeName}" does not exist!`);
		}

		return new Proxy({}, {
			get(target, name, receiver) {
				name = name.toString();

				if (['binary', 'data', 'json'].includes(name)) {
					const executionData = that.getNodeExecutionData(nodeName, shortSyntax, undefined);

					if (executionData.length <= that.itemIndex) {
						throw new Error(`No data found for item-index: "${that.itemIndex}"`);
					}

					if (['data', 'json'].includes(name as string)) {
						// JSON-Data
						return executionData[that.itemIndex].json;
					} else if (name === 'binary') {
						// Binary-Data
						const returnData: IDataObject = {};

						if (!executionData[that.itemIndex].binary) {
							return returnData;
						}

						const binaryKeyData = executionData[that.itemIndex].binary!;
						for (const keyName of Object.keys(binaryKeyData)) {

							returnData[keyName] = {};

							const binaryData = binaryKeyData[keyName];
							for (const propertyName in binaryData) {
								if (propertyName === 'data') {
									// Skip the data property
									continue;
								}
								(returnData[keyName] as IDataObject)[propertyName] = binaryData[propertyName];
							}
						}

						return returnData;
					}

				} else if (name === 'context') {
					return that.nodeContextGetter(nodeName);
				} else if (name === 'parameter') {
					// Get node parameter data
					return that.nodeParameterGetter(nodeName);
				} else if (name === 'runIndex') {
					if (that.runExecutionData === null || !that.runExecutionData.resultData.runData[nodeName]) {
						return -1;
					}
					return that.runExecutionData.resultData.runData[nodeName].length - 1;
				}

				return Reflect.get(target, name, receiver);
			}
		});
	}



	/**
	 * Returns a proxy to query data from the environment
	 *
	 * @private
	 * @returns
	 * @memberof WorkflowDataGetter
	 */
	private envGetter() {
		return new Proxy({}, {
			get(target, name, receiver) {
				return process.env[name.toString()];
			}
		});
	}



	/**
	 * Returns a proxt to query data from the workflow
	 *
	 * @private
	 * @returns
	 * @memberof WorkflowDataProxy
	 */
	private workflowGetter() {
		const allowedValues = [
			'active',
			'id',
			'name',
		];
		const that = this;

		return new Proxy({}, {
			get(target, name, receiver) {
				if (!allowedValues.includes(name.toString())) {
					throw new Error(`The key "${name.toString()}" is not supported!`);
				}

				// @ts-ignore
				return that.workflow[name.toString()];
			}
		});
	}



	/**
	 * Returns a proxy to query data of all nodes
	 *
	 * @private
	 * @returns
	 * @memberof WorkflowDataGetter
	 */
	private nodeGetter() {
		const that = this;
		return new Proxy({}, {
			get(target, name, receiver) {
				return that.nodeDataGetter(name.toString());
			}
		});
	}



	/**
	 * Returns the data proxy object which allows to query data from current run
	 *
	 * @returns
	 * @memberof WorkflowDataGetter
	 */
	getDataProxy(): IWorkflowDataProxyData {
		const that = this;

		const base = {
			$binary: {}, // Placeholder
			$data: {}, // Placeholder
			$env: this.envGetter(),
			$evaluateExpression: (expression: string) => { },  // Placeholder
			$item: (itemIndex: number, runIndex?: number) => {
				const defaultReturnRunIndex = runIndex === undefined ? -1 : runIndex;
				const dataProxy = new WorkflowDataProxy(this.workflow, this.runExecutionData, this.runIndex, itemIndex, this.activeNodeName, this.connectionInputData, defaultReturnRunIndex);
				return dataProxy.getDataProxy();
			},
			$items: (nodeName?: string, outputIndex?: number, runIndex?: number) => {
				let executionData: INodeExecutionData[];

				if (nodeName === undefined) {
					executionData = that.connectionInputData;
				} else {
					outputIndex = outputIndex || 0;
					runIndex = runIndex === undefined ? -1 : runIndex;
					executionData = that.getNodeExecutionData(nodeName, false, outputIndex, runIndex);
				}

				return executionData;
			},
			$json: {}, // Placeholder
			$node: this.nodeGetter(),
			$parameter: this.nodeParameterGetter(this.activeNodeName),
			$runIndex: this.runIndex,
			$workflow: this.workflowGetter(),
		};

		return new Proxy(base, {
			get(target, name, receiver) {
				if (['$data', '$json'].includes(name as string)) {
					// @ts-ignore
					return that.nodeDataGetter(that.activeNodeName, true).json;
				} else if (name === '$binary') {
					// @ts-ignore
					return that.nodeDataGetter(that.activeNodeName, true).binary;
				}

				return Reflect.get(target, name, receiver);
			}
		});
	}
}