chore: Add Cohere Rerank component for document reranking

src/backend/base/langflow/components/retrievers/CohereRerank.py

@@ -0,0 +1,51 @@
+from typing import List
+
+from langchain.retrievers import ContextualCompressionRetriever
+from langchain_cohere import CohereRerank
+
+from langflow.base.vectorstores.model import LCVectorStoreComponent
+from langflow.field_typing import Retriever
+from langflow.io import DropdownInput, HandleInput, IntInput, MultilineInput, SecretStrInput, TextInput
+from langflow.schema import Data
+
+
+class CohereRerankComponent(LCVectorStoreComponent):
+    display_name = "Cohere Rerank"
+    description = "Rerank documents using the Cohere API."
+    icon = "Cohere"
+
+    inputs = [
+        MultilineInput(
+            name="search_query",
+            display_name="Search Query",
+        ),
+        DropdownInput(
+            name="model",
+            display_name="Model",
+            options=[
+                "rerank-english-v3.0",
+                "rerank-multilingual-v3.0",
+                "rerank-english-v2.0",
+                "rerank-multilingual-v2.0",
+            ],
+            value="rerank-english-v3.0",
+        ),
+        SecretStrInput(name="api_key", display_name="API Key"),
+        IntInput(name="top_n", display_name="Top N", value=3),
+        TextInput(name="user_agent", display_name="User Agent", value="langflow", advanced=True),
+        HandleInput(name="retriever", display_name="Retriever", input_types=["Retriever"]),
+    ]
+
+    def build_base_retriever(self) -> Retriever:
+        cohere_reranker = CohereRerank(
+            api_key=self.api_key, model=self.model, top_n=self.top_n, user_agent=self.user_agent
+        )
+        retriever = ContextualCompressionRetriever(base_compressor=cohere_reranker, base_retriever=self.retriever)
+        return retriever
+
+    async def search_documents(self) -> List[Data]:
+        retriever = self.build_base_retriever()
+        documents = await retriever.ainvoke(self.search_query)
+        data = self.to_data(documents)
+        self.status = data
+        return data