Flowise/packages/components/nodes/tools/CustomTool/core.ts

import { z } from 'zod'
import { RunnableConfig } from '@langchain/core/runnables'
import { StructuredTool, ToolParams } from '@langchain/core/tools'
import { CallbackManagerForToolRun, Callbacks, CallbackManager, parseCallbackConfigArg } from '@langchain/core/callbacks/manager'
import { executeJavaScriptCode, createCodeExecutionSandbox } from '../../../src/utils'
import { ICommonObject } from '../../../src/Interface'

class ToolInputParsingException extends Error {
    output?: string

    constructor(message: string, output?: string) {
        super(message)
        this.output = output
    }
}

export interface BaseDynamicToolInput extends ToolParams {
    name: string
    description: string
    code: string
    returnDirect?: boolean
}

export interface DynamicStructuredToolInput<
    // eslint-disable-next-line
    T extends z.ZodObject<any, any, any, any> = z.ZodObject<any, any, any, any>
> extends BaseDynamicToolInput {
    func?: (input: z.infer<T>, runManager?: CallbackManagerForToolRun) => Promise<string>
    schema: T
}

export class DynamicStructuredTool<
    // eslint-disable-next-line
    T extends z.ZodObject<any, any, any, any> = z.ZodObject<any, any, any, any>
> extends StructuredTool {
    name: string

    description: string

    code: string

    func: DynamicStructuredToolInput['func']

    // @ts-ignore
    schema: T
    private variables: any[]
    private flowObj: any

    constructor(fields: DynamicStructuredToolInput<T>) {
        super(fields)
        this.name = fields.name
        this.description = fields.description
        this.code = fields.code
        this.func = fields.func
        this.returnDirect = fields.returnDirect ?? this.returnDirect
        this.schema = fields.schema
    }

    async call(
        arg: z.output<T>,
        configArg?: RunnableConfig | Callbacks,
        tags?: string[],
        flowConfig?: { sessionId?: string; chatId?: string; input?: string; state?: ICommonObject }
    ): Promise<string> {
        const config = parseCallbackConfigArg(configArg)
        if (config.runName === undefined) {
            config.runName = this.name
        }
        let parsed
        try {
            parsed = await this.schema.parseAsync(arg)
        } catch (e) {
            throw new ToolInputParsingException(`Received tool input did not match expected schema`, JSON.stringify(arg))
        }
        const callbackManager_ = await CallbackManager.configure(
            config.callbacks,
            this.callbacks,
            config.tags || tags,
            this.tags,
            config.metadata,
            this.metadata,
            { verbose: this.verbose }
        )
        const runManager = await callbackManager_?.handleToolStart(
            this.toJSON(),
            typeof parsed === 'string' ? parsed : JSON.stringify(parsed),
            undefined,
            undefined,
            undefined,
            undefined,
            config.runName
        )
        let result
        try {
            result = await this._call(parsed, runManager, flowConfig)
        } catch (e) {
            await runManager?.handleToolError(e)
            throw e
        }
        if (result && typeof result !== 'string') {
            result = JSON.stringify(result)
        }
        await runManager?.handleToolEnd(result)
        return result
    }

    // @ts-ignore
    protected async _call(
        arg: z.output<T>,
        _?: CallbackManagerForToolRun,
        flowConfig?: { sessionId?: string; chatId?: string; input?: string; state?: ICommonObject }
    ): Promise<string> {
        // Create additional sandbox variables for tool arguments
        const additionalSandbox: ICommonObject = {}

        if (typeof arg === 'object' && Object.keys(arg).length) {
            for (const item in arg) {
                additionalSandbox[`$${item}`] = arg[item]
            }
        }

        // Prepare flow object for sandbox
        const flow = this.flowObj ? { ...this.flowObj, ...flowConfig } : {}

        const sandbox = createCodeExecutionSandbox('', this.variables || [], flow, additionalSandbox)

        let response = await executeJavaScriptCode(this.code, sandbox)

        if (typeof response === 'object') {
            response = JSON.stringify(response)
        }

        return response
    }

    setVariables(variables: any[]) {
        this.variables = variables
    }

    setFlowObject(flow: any) {
        this.flowObj = flow
    }
}