Compression Retriever - Cohere Rerank

2026-06-29 15:01:11 +03:00 · 2023-12-22 12:12:04 +05:30
parent 56b043264a
commit 94236c4b5f
3 changed files with 135 additions and 0 deletions
@@ -0,0 +1,51 @@
+import { Callbacks } from 'langchain/callbacks'
+import { Document } from 'langchain/document'
+import { BaseDocumentCompressor } from 'langchain/retrievers/document_compressors'
+import axios from 'axios'
+export class CohereRerank extends BaseDocumentCompressor {
+    private cohereAPIKey: any
+    private COHERE_API_URL = 'https://api.cohere.ai/v1/rerank'
+    private model: string
+
+    constructor(cohereAPIKey: string, model: string) {
+        super()
+        this.cohereAPIKey = cohereAPIKey
+        this.model = model
+    }
+    async compressDocuments(
+        documents: Document<Record<string, any>>[],
+        query: string,
+        _?: Callbacks | undefined
+    ): Promise<Document<Record<string, any>>[]> {
+        // avoid empty api call
+        if (documents.length === 0) {
+            return []
+        }
+        const config = {
+            headers: {
+                Authorization: `Bearer ${this.cohereAPIKey}`,
+                'Content-Type': 'application/json',
+                Accept: 'application/json'
+            }
+        }
+        const data = {
+            model: this.model,
+            max_chunks_per_doc: 10,
+            query: query,
+            return_documents: false,
+            documents: documents.map((doc) => doc.pageContent)
+        }
+        try {
+            let returnedDocs = await axios.post(this.COHERE_API_URL, data, config)
+            const finalResults: Document<Record<string, any>>[] = []
+            returnedDocs.data.results.forEach((result: any) => {
+                const doc = documents[result.index]
+                doc.metadata.relevance_score = result.relevance_score
+                finalResults.push(doc)
+            })
+            return finalResults
+        } catch (error) {
+            return documents
+        }
+    }
+}