Add doc meta data. (#4442)

### What problem does this PR solve?

#3690

### Type of change

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

api/db/db_models.py

@@ -760,6 +760,7 @@ class Document(DataBaseModel):
         default="")
     process_begin_at = DateTimeField(null=True, index=True)
     process_duation = FloatField(default=0)
+    meta_fields = JSONField(null=True, default={})
 
     run = CharField(
         max_length=1,
@@ -1112,3 +1113,10 @@ def migrate_db():
             )
         except Exception:
             pass
+        try:
+            migrate(
+                migrator.add_column("document", "meta_fields",
+                                    JSONField(null=True, default={}))
+            )
+        except Exception:
+            pass

api/db/services/dialog_service.py

@@ -122,15 +122,17 @@ def kb_prompt(kbinfos, max_tokens):
             knowledges = knowledges[:i]
             break
 
+    #docs = DocumentService.get_by_ids([ck["doc_id"] for ck in kbinfos["chunks"][:chunks_num]])
+    #docs = {d.id: d.meta_fields for d in docs}
+
     doc2chunks = defaultdict(list)
-    for i, ck in enumerate(kbinfos["chunks"]):
-        if i >= chunks_num:
-            break
+    for ck in kbinfos["chunks"][:chunks_num]:
         doc2chunks[ck["docnm_kwd"]].append(ck["content_with_weight"])
 
     knowledges = []
     for nm, chunks in doc2chunks.items():
-        txt = f"Document: {nm} \nContains the following relevant fragments:\n"
+        txt = f"Document: {nm} \n"
+        txt += "Contains the following relevant fragments:\n"
         for i, chunk in enumerate(chunks, 1):
             txt += f"{i}. {chunk}\n"
         knowledges.append(txt)