Feature/Add support for state-based metadata filter to Retriever Tool (#3501)

* Added support for state-based metadata filter to Retriever Tool

* Update RetrieverTool.ts

---------

Co-authored-by: Henry Heng <henryheng@flowiseai.com>

packages/components/nodes/tools/RetrieverTool/RetrieverTool.ts

@@ -1,11 +1,121 @@
 import { z } from 'zod'
-import { DynamicStructuredTool } from '@langchain/core/tools'
+import { CallbackManager, CallbackManagerForToolRun, Callbacks, parseCallbackConfigArg } from '@langchain/core/callbacks/manager'
-import { CallbackManagerForToolRun } from '@langchain/core/callbacks/manager'
+import { BaseDynamicToolInput, DynamicTool, StructuredTool, ToolInputParsingException } from '@langchain/core/tools'
-import { DynamicTool } from '@langchain/core/tools'
 import { BaseRetriever } from '@langchain/core/retrievers'
-import { INode, INodeData, INodeParams } from '../../../src/Interface'
+import { ICommonObject, INode, INodeData, INodeParams } from '../../../src/Interface'
 import { getBaseClasses } from '../../../src/utils'
 import { SOURCE_DOCUMENTS_PREFIX } from '../../../src/agents'
+import { RunnableConfig } from '@langchain/core/runnables'
+import { customGet } from '../../sequentialagents/commonUtils'
+import { VectorStoreRetriever } from '@langchain/core/vectorstores'
+
+const howToUse = `Add additional filters to vector store. You can also filter with flow config, including the current "state":
+- \`$flow.sessionId\`
+- \`$flow.chatId\`
+- \`$flow.chatflowId\`
+- \`$flow.input\`
+- \`$flow.state\`
+`
+
+type ZodObjectAny = z.ZodObject<any, any, any, any>
+type IFlowConfig = { sessionId?: string; chatId?: string; input?: string; state?: ICommonObject }
+interface DynamicStructuredToolInput<T extends z.ZodObject<any, any, any, any> = z.ZodObject<any, any, any, any>>
+    extends BaseDynamicToolInput {
+    func?: (input: z.infer<T>, runManager?: CallbackManagerForToolRun, flowConfig?: IFlowConfig) => Promise<string>
+    schema: T
+}
+
+class DynamicStructuredTool<T extends z.ZodObject<any, any, any, any> = z.ZodObject<any, any, any, any>> extends StructuredTool<
+    T extends ZodObjectAny ? T : ZodObjectAny
+> {
+    static lc_name() {
+        return 'DynamicStructuredTool'
+    }
+
+    name: string
+
+    description: string
+
+    func: DynamicStructuredToolInput['func']
+
+    // @ts-ignore
+    schema: T
+
+    private flowObj: any
+
+    constructor(fields: DynamicStructuredToolInput<T>) {
+        super(fields)
+        this.name = fields.name
+        this.description = fields.description
+        this.func = fields.func
+        this.returnDirect = fields.returnDirect ?? this.returnDirect
+        this.schema = fields.schema
+    }
+
+    async call(arg: any, configArg?: RunnableConfig | Callbacks, tags?: string[], flowConfig?: IFlowConfig): 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 _call(arg: any, runManager?: CallbackManagerForToolRun, flowConfig?: IFlowConfig): Promise<string> {
+        let flowConfiguration: ICommonObject = {}
+        if (typeof arg === 'object' && Object.keys(arg).length) {
+            for (const item in arg) {
+                flowConfiguration[`$${item}`] = arg[item]
+            }
+        }
+
+        // inject flow properties
+        if (this.flowObj) {
+            flowConfiguration['$flow'] = { ...this.flowObj, ...flowConfig }
+        }
+
+        return this.func!(arg as any, runManager, flowConfiguration)
+    }
+
+    setFlowObject(flow: any) {
+        this.flowObj = flow
+    }
+}
 
 class Retriever_Tools implements INode {
     label: string
@@ -22,7 +132,7 @@ class Retriever_Tools implements INode {
     constructor() {
         this.label = 'Retriever Tool'
         this.name = 'retrieverTool'
-        this.version = 2.0
+        this.version = 3.0
         this.type = 'RetrieverTool'
         this.icon = 'retrievertool.svg'
         this.category = 'Tools'
@@ -53,23 +163,55 @@ class Retriever_Tools implements INode {
                 name: 'returnSourceDocuments',
                 type: 'boolean',
                 optional: true
+            },
+            {
+                label: 'Additional Metadata Filter',
+                name: 'retrieverToolMetadataFilter',
+                type: 'json',
+                description: 'Add additional metadata filter on top of the existing filter from vector store',
+                optional: true,
+                additionalParams: true,
+                hint: {
+                    label: 'What can you filter?',
+                    value: howToUse
+                }
             }
         ]
     }
 
-    async init(nodeData: INodeData): Promise<any> {
+    async init(nodeData: INodeData, _: string, options: ICommonObject): Promise<any> {
         const name = nodeData.inputs?.name as string
         const description = nodeData.inputs?.description as string
         const retriever = nodeData.inputs?.retriever as BaseRetriever
         const returnSourceDocuments = nodeData.inputs?.returnSourceDocuments as boolean
+        const retrieverToolMetadataFilter = nodeData.inputs?.retrieverToolMetadataFilter
 
         const input = {
             name,
             description
         }
 
-        const func = async ({ input }: { input: string }, runManager?: CallbackManagerForToolRun) => {
+        const flow = { chatflowId: options.chatflowid }
-            const docs = await retriever.getRelevantDocuments(input, runManager?.getChild('retriever'))
+
+        const func = async ({ input }: { input: string }, _?: CallbackManagerForToolRun, flowConfig?: IFlowConfig) => {
+            if (retrieverToolMetadataFilter) {
+                const flowObj = flowConfig
+
+                const metadatafilter =
+                    typeof retrieverToolMetadataFilter === 'object' ? retrieverToolMetadataFilter : JSON.parse(retrieverToolMetadataFilter)
+                const newMetadataFilter: any = {}
+                for (const key in metadatafilter) {
+                    let value = metadatafilter[key]
+                    if (value.startsWith('$flow')) {
+                        value = customGet(flowObj, value)
+                    }
+                    newMetadataFilter[key] = value
+                }
+
+                const vectorStore = (retriever as VectorStoreRetriever<any>).vectorStore
+                vectorStore.filter = newMetadataFilter
+            }
+            const docs = await retriever.invoke(input)
             const content = docs.map((doc) => doc.pageContent).join('\n\n')
             const sourceDocuments = JSON.stringify(docs)
             return returnSourceDocuments ? content + SOURCE_DOCUMENTS_PREFIX + sourceDocuments : content
@@ -80,6 +222,7 @@ class Retriever_Tools implements INode {
         }) as any
 
         const tool = new DynamicStructuredTool({ ...input, func, schema })
+        tool.setFlowObject(flow)
         return tool
     }
 }