Flowise/packages/components/nodes/utilities/CustomFunction/CustomFunction.ts

import { flatten } from 'lodash'
import { type StructuredTool } from '@langchain/core/tools'
import { NodeVM } from '@flowiseai/nodevm'
import { DataSource } from 'typeorm'
import { availableDependencies, defaultAllowBuiltInDep, getVars, handleEscapeCharacters, prepareSandboxVars } from '../../../src/utils'
import { ICommonObject, IDatabaseEntity, INode, INodeData, INodeOutputsValue, INodeParams } from '../../../src/Interface'

class CustomFunction_Utilities implements INode {
    label: string
    name: string
    version: number
    description: string
    type: string
    icon: string
    category: string
    tags: string[]
    baseClasses: string[]
    inputs: INodeParams[]
    outputs: INodeOutputsValue[]

    constructor() {
        this.label = 'Custom JS Function'
        this.name = 'customFunction'
        this.version = 3.0
        this.type = 'CustomFunction'
        this.icon = 'customfunction.svg'
        this.category = 'Utilities'
        this.description = `Execute custom javascript function`
        this.baseClasses = [this.type, 'Utilities']
        this.tags = ['Utilities']
        this.inputs = [
            {
                label: 'Input Variables',
                name: 'functionInputVariables',
                description: 'Input variables can be used in the function with prefix $. For example: $var',
                type: 'json',
                optional: true,
                acceptVariable: true,
                list: true
            },
            {
                label: 'Function Name',
                name: 'functionName',
                type: 'string',
                optional: true,
                placeholder: 'My Function'
            },
            {
                label: 'Additional Tools',
                description: 'Tools can be used in the function with $tools.{tool_name}.invoke(args)',
                name: 'tools',
                type: 'Tool',
                list: true,
                optional: true
            },
            {
                label: 'Javascript Function',
                name: 'javascriptFunction',
                type: 'code'
            }
        ]
        this.outputs = [
            {
                label: 'Output',
                name: 'output',
                baseClasses: ['string', 'number', 'boolean', 'json', 'array']
            },
            {
                label: 'Ending Node',
                name: 'EndingNode',
                baseClasses: [this.type]
            }
        ]
    }

    async init(nodeData: INodeData, input: string, options: ICommonObject): Promise<any> {
        const isEndingNode = nodeData?.outputs?.output === 'EndingNode'
        if (isEndingNode && !options.isRun) return // prevent running both init and run twice

        const javascriptFunction = nodeData.inputs?.javascriptFunction as string
        const functionInputVariablesRaw = nodeData.inputs?.functionInputVariables
        const appDataSource = options.appDataSource as DataSource
        const databaseEntities = options.databaseEntities as IDatabaseEntity
        const tools = Object.fromEntries((flatten(nodeData.inputs?.tools) as StructuredTool[])?.map((tool) => [tool.name, tool]) ?? [])

        const variables = await getVars(appDataSource, databaseEntities, nodeData)
        const flow = {
            chatflowId: options.chatflowid,
            sessionId: options.sessionId,
            chatId: options.chatId,
            rawOutput: options.rawOutput || '',
            input
        }

        let inputVars: ICommonObject = {}
        if (functionInputVariablesRaw) {
            try {
                inputVars =
                    typeof functionInputVariablesRaw === 'object' ? functionInputVariablesRaw : JSON.parse(functionInputVariablesRaw)
            } catch (exception) {
                throw new Error('Invalid JSON in the Custom Function Input Variables: ' + exception)
            }
        }

        // Some values might be a stringified JSON, parse it
        for (const key in inputVars) {
            let value = inputVars[key]
            if (typeof value === 'string') {
                value = handleEscapeCharacters(value, true)
                if (value.startsWith('{') && value.endsWith('}')) {
                    try {
                        value = JSON.parse(value)
                    } catch (e) {
                        // ignore
                    }
                }
                inputVars[key] = value
            }
        }

        let sandbox: any = {
            $input: input,
            util: undefined,
            Symbol: undefined,
            child_process: undefined,
            fs: undefined,
            process: undefined
        }
        sandbox['$vars'] = prepareSandboxVars(variables)
        sandbox['$flow'] = flow
        sandbox['$tools'] = tools

        if (Object.keys(inputVars).length) {
            for (const item in inputVars) {
                sandbox[`$${item}`] = inputVars[item]
            }
        }

        const builtinDeps = process.env.TOOL_FUNCTION_BUILTIN_DEP
            ? defaultAllowBuiltInDep.concat(process.env.TOOL_FUNCTION_BUILTIN_DEP.split(','))
            : defaultAllowBuiltInDep
        const externalDeps = process.env.TOOL_FUNCTION_EXTERNAL_DEP ? process.env.TOOL_FUNCTION_EXTERNAL_DEP.split(',') : []
        const deps = availableDependencies.concat(externalDeps)

        const nodeVMOptions = {
            console: 'inherit',
            sandbox,
            require: {
                external: { modules: deps },
                builtin: builtinDeps
            },
            eval: false,
            wasm: false,
            timeout: 10000
        } as any

        const vm = new NodeVM(nodeVMOptions)
        try {
            const response = await vm.run(`module.exports = async function() {${javascriptFunction}}()`, __dirname)

            if (typeof response === 'string' && !isEndingNode) {
                return handleEscapeCharacters(response, false)
            }
            return response
        } catch (e) {
            throw new Error(e)
        }
    }

    async run(nodeData: INodeData, input: string, options: ICommonObject): Promise<string> {
        return await this.init(nodeData, input, { ...options, isRun: true })
    }
}

module.exports = { nodeClass: CustomFunction_Utilities }