support graph (#1152)

### What problem does this PR solve?

#918 
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

graph/component/cite.py

@@ -0,0 +1,75 @@
+#
+#  Copyright 2024 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+from abc import ABC
+
+import pandas as pd
+
+from api.db import LLMType
+from api.db.services.knowledgebase_service import KnowledgebaseService
+from api.db.services.llm_service import LLMBundle
+from api.settings import retrievaler
+from graph.component.base import ComponentBase, ComponentParamBase
+
+
+class CiteParam(ComponentParamBase):
+
+    """
+    Define the Retrieval component parameters.
+    """
+    def __init__(self):
+        super().__init__()
+        self.cite_sources = []
+
+    def check(self):
+        self.check_empty(self.cite_source, "Please specify where you want to cite from.")
+
+
+class Cite(ComponentBase, ABC):
+    component_name = "Cite"
+
+    def _run(self, history, **kwargs):
+        input = "\n- ".join(self.get_input()["content"])
+        sources = [self._canvas.get_component(cpn_id).output()[1] for cpn_id in self._param.cite_source]
+        query = []
+        for role, cnt in history[::-1][:self._param.message_history_window_size]:
+            if role != "user":continue
+            query.append(cnt)
+        query = "\n".join(query)
+
+        kbs = KnowledgebaseService.get_by_ids(self._param.kb_ids)
+        if not kbs:
+            raise ValueError("Can't find knowledgebases by {}".format(self._param.kb_ids))
+        embd_nms = list(set([kb.embd_id for kb in kbs]))
+        assert len(embd_nms) == 1, "Knowledge bases use different embedding models."
+
+        embd_mdl = LLMBundle(kbs[0].tenant_id, LLMType.EMBEDDING, embd_nms[0])
+
+        rerank_mdl = None
+        if self._param.rerank_id:
+            rerank_mdl = LLMBundle(kbs[0].tenant_id, LLMType.RERANK, self._param.rerank_id)
+
+        kbinfos = retrievaler.retrieval(query, embd_mdl, kbs[0].tenant_id, self._param.kb_ids,
+                                        1, self._param.top_n,
+                                        self._param.similarity_threshold, 1 - self._param.keywords_similarity_weight,
+                                        aggs=False, rerank_mdl=rerank_mdl)
+
+        if not kbinfos["chunks"]: return pd.DataFrame()
+        df = pd.DataFrame(kbinfos["chunks"])
+        df["content"] = df["content_with_weight"]
+        del df["content_with_weight"]
+        return df
+
+