Refine search query. (#5235)

### What problem does this PR solve?

#5173
#5214

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/db/services/dialog_service.py

         "Once you have all the information you need, continue your reasoning.\n\n"
         "-- Example --\n"
         "Question: \"Find the minimum number of vertices in a Steiner tree that includes all specified vertices in a given tree.\"\n"
-        "Assistant thinking steps:\n"
-        "- I need to understand what a Steiner tree is and how to compute the minimum number of vertices required to include all specified vertices in a given tree.\n\n"
         "Assistant:\n"
-        f"{BEGIN_SEARCH_QUERY}Minimum Steiner Tree problem in trees{END_SEARCH_QUERY}\n\n"
-        "(System returns processed information from relevant web pages)\n\n"
-        "Assistant continues reasoning with the new information...\n\n"
+        "  - I need to understand what a Steiner tree is.\n\n" 
+        f"    {BEGIN_SEARCH_QUERY}What's Steiner tree{END_SEARCH_QUERY}\n\n"
+        f"    {BEGIN_SEARCH_RESULT}\n(System returns processed information from relevant web pages)\n{END_SEARCH_RESULT}\n\n"
+        "User:\nContinues reasoning with the new information.\n\n"
+        "Assistant:\n"
+        "  - I need to understand what the difference between minimum number of vertices and edges in the Steiner tree is.\n\n" 
+        f"    {BEGIN_SEARCH_QUERY}What's the difference between minimum number of vertices and edges in the Steiner tree{END_SEARCH_QUERY}\n\n"
+        f"    {BEGIN_SEARCH_RESULT}\n(System returns processed information from relevant web pages)\n{END_SEARCH_RESULT}\n\n"
+        "User:\nContinues reasoning with the new information...\n\n"
         "**Remember**:\n"
         f"- You have a dataset to search, so you just provide a proper search query.\n"
         f"- Use {BEGIN_SEARCH_QUERY} to request a dataset search and end with {END_SEARCH_QUERY}.\n"
 
         query_think = ""
         if msg_hisotry[-1]["role"] != "user":
-            msg_hisotry.append({"role": "user", "content": "Continues reasoning with the new information...\n"})
+            msg_hisotry.append({"role": "user", "content": "Continues reasoning with the new information.\n"})
         for ans in chat_mdl.chat_streamly(reason_prompt, msg_hisotry, {"temperature": 0.7}):
             ans = re.sub(r"<think>.*</think>", "", ans, flags=re.DOTALL)
             if not ans:
         think += rm_query_tags(query_think)
         all_reasoning_steps.append(query_think)
         msg_hisotry.append({"role": "assistant", "content": query_think})
-        search_query = extract_between(query_think, BEGIN_SEARCH_QUERY, END_SEARCH_QUERY)
-        if not search_query:
+        queries = extract_between(query_think, BEGIN_SEARCH_QUERY, END_SEARCH_QUERY)
+        if not queries:
             if ii > 0:
                 break
-            search_query = question
-            txt = f"\n{BEGIN_SEARCH_QUERY}{question}{END_SEARCH_QUERY}\n\n"
-            think += txt
-            msg_hisotry[-1]["content"] += txt
-
-        logging.info(f"[THINK]Query: {ii}. {search_query}")
-        think += f"\n\n> {ii+1}. {search_query}\n\n"
-        yield {"answer": think + "</think>", "reference": {}, "audio_binary": None}
-
-        summary_think = ""
-        # The search query has been searched in previous steps.
-        if search_query in executed_search_queries:
-            summary_think = f"\n{BEGIN_SEARCH_RESULT}\nYou have searched this query. Please refer to previous results.\n{END_SEARCH_RESULT}\n"
-            yield {"answer": think + summary_think + "</think>", "reference": {}, "audio_binary": None}
-            all_reasoning_steps.append(summary_think)
-            msg_hisotry.append({"role": "assistant", "content": summary_think})
-            think += summary_think
-            continue
+            queries = [question]
+
+        for search_query in queries:
+            logging.info(f"[THINK]Query: {ii}. {search_query}")
+            think += f"\n\n> {ii+1}. {search_query}\n\n"
+            yield {"answer": think + "</think>", "reference": {}, "audio_binary": None}
+
+            summary_think = ""
+            # The search query has been searched in previous steps.
+            if search_query in executed_search_queries:
+                summary_think = f"\n{BEGIN_SEARCH_RESULT}\nYou have searched this query. Please refer to previous results.\n{END_SEARCH_RESULT}\n"
+                yield {"answer": think + summary_think + "</think>", "reference": {}, "audio_binary": None}
+                all_reasoning_steps.append(summary_think)
+                msg_hisotry.append({"role": "assistant", "content": summary_think})
+                think += summary_think
+                continue
 
-        truncated_prev_reasoning = ""
-        for i, step in enumerate(all_reasoning_steps):
-            truncated_prev_reasoning += f"Step {i + 1}: {step}\n\n"
+            truncated_prev_reasoning = ""
+            for i, step in enumerate(all_reasoning_steps):
+                truncated_prev_reasoning += f"Step {i + 1}: {step}\n\n"
 
-        prev_steps = truncated_prev_reasoning.split('\n\n')
-        if len(prev_steps) <= 5:
-            truncated_prev_reasoning = '\n\n'.join(prev_steps)
-        else:
-            truncated_prev_reasoning = ''
-            for i, step in enumerate(prev_steps):
-                if i == 0 or i >= len(prev_steps) - 4 or BEGIN_SEARCH_QUERY in step or BEGIN_SEARCH_RESULT in step:
-                    truncated_prev_reasoning += step + '\n\n'
-                else:
-                    if truncated_prev_reasoning[-len('\n\n...\n\n'):] != '\n\n...\n\n':
-                        truncated_prev_reasoning += '...\n\n'
-        truncated_prev_reasoning = truncated_prev_reasoning.strip('\n')
-
-        kbinfos = settings.retrievaler.retrieval(search_query, embd_mdl, tenant_ids, kb_ids, 1, top_n,
-                                                 similarity_threshold,
-                                                 vector_similarity_weight
-                                                 )
-        # Merge chunk info for citations
-        if not chunk_info["chunks"]:
-            for k in chunk_info.keys():
-                chunk_info[k] = kbinfos[k]
-        else:
-            cids = [c["chunk_id"] for c in chunk_info["chunks"]]
-            for c in kbinfos["chunks"]:
-                if c["chunk_id"] in cids:
-                    continue
-                chunk_info["chunks"].append(c)
-            dids = [d["doc_id"] for d in chunk_info["doc_aggs"]]
-            for d in kbinfos["doc_aggs"]:
-                if d["doc_id"] in dids:
+            prev_steps = truncated_prev_reasoning.split('\n\n')
+            if len(prev_steps) <= 5:
+                truncated_prev_reasoning = '\n\n'.join(prev_steps)
+            else:
+                truncated_prev_reasoning = ''
+                for i, step in enumerate(prev_steps):
+                    if i == 0 or i >= len(prev_steps) - 4 or BEGIN_SEARCH_QUERY in step or BEGIN_SEARCH_RESULT in step:
+                        truncated_prev_reasoning += step + '\n\n'
+                    else:
+                        if truncated_prev_reasoning[-len('\n\n...\n\n'):] != '\n\n...\n\n':
+                            truncated_prev_reasoning += '...\n\n'
+            truncated_prev_reasoning = truncated_prev_reasoning.strip('\n')
+
+            kbinfos = settings.retrievaler.retrieval(search_query, embd_mdl, tenant_ids, kb_ids, 1, top_n,
+                                                     similarity_threshold,
+                                                     vector_similarity_weight
+                                                     )
+            # Merge chunk info for citations
+            if not chunk_info["chunks"]:
+                for k in chunk_info.keys():
+                    chunk_info[k] = kbinfos[k]
+            else:
+                cids = [c["chunk_id"] for c in chunk_info["chunks"]]
+                for c in kbinfos["chunks"]:
+                    if c["chunk_id"] in cids:
+                        continue
+                    chunk_info["chunks"].append(c)
+                dids = [d["doc_id"] for d in chunk_info["doc_aggs"]]
+                for d in kbinfos["doc_aggs"]:
+                    if d["doc_id"] in dids:
+                        continue
+                    chunk_info["doc_aggs"].append(d)
+
+            think += "\n\n"
+            for ans in chat_mdl.chat_streamly(
+                    relevant_extraction_prompt.format(
+                        prev_reasoning=truncated_prev_reasoning,
+                        search_query=search_query,
+                        document="\n".join(kb_prompt(kbinfos, 512))
+                    ),
+                    [{"role": "user",
+                     "content": f'Now you should analyze each web page and find helpful information based on the current search query "{search_query}" and previous reasoning steps.'}],
+                    {"temperature": 0.7}):
+                ans = re.sub(r"<think>.*</think>", "", ans, flags=re.DOTALL)
+                if not ans:
                     continue
-                chunk_info["doc_aggs"].append(d)
-
-        think += "\n\n"
-        for ans in chat_mdl.chat_streamly(
-                relevant_extraction_prompt.format(
-                    prev_reasoning=truncated_prev_reasoning,
-                    search_query=search_query,
-                    document="\n".join(kb_prompt(kbinfos, 512))
-                ),
-                [{"role": "user",
-                 "content": f'Now you should analyze each web page and find helpful information based on the current search query "{search_query}" and previous reasoning steps.'}],
-                {"temperature": 0.7}):
-            ans = re.sub(r"<think>.*</think>", "", ans, flags=re.DOTALL)
-            if not ans:
-                continue
-            summary_think = ans
-            yield {"answer": think + rm_result_tags(summary_think) + "</think>", "reference": {}, "audio_binary": None}
-
-        all_reasoning_steps.append(summary_think)
-        msg_hisotry.append(
-            {"role": "assistant", "content": f"\n\n{BEGIN_SEARCH_RESULT}{summary_think}{END_SEARCH_RESULT}\n\n"})
-        think += rm_result_tags(summary_think)
-        logging.info(f"[THINK]Summary: {ii}. {summary_think}")
+                summary_think = ans
+                yield {"answer": think + rm_result_tags(summary_think) + "</think>", "reference": {}, "audio_binary": None}
+
+            all_reasoning_steps.append(summary_think)
+            msg_hisotry.append(
+                {"role": "assistant", "content": f"\n\n{BEGIN_SEARCH_RESULT}{summary_think}{END_SEARCH_RESULT}\n\n"})
+            think += rm_result_tags(summary_think)
+            logging.info(f"[THINK]Summary: {ii}. {summary_think}")
 
     yield think + "</think>"

rag/nlp/__init__.py

 import logging
 import random
 from collections import Counter
-from typing import Optional
 
 from rag.utils import num_tokens_from_string
 from . import rag_tokenizer
     return cks, images
 
 
-def extract_between(text: str, start_tag: str, end_tag: str) -> Optional[str]:
+def extract_between(text: str, start_tag: str, end_tag: str) -> list[str]:
     pattern = re.escape(start_tag) + r"(.*?)" + re.escape(end_tag)
-    matches = re.findall(pattern, text, flags=re.DOTALL)
-    if matches:
-        return matches[-1].strip()
-    return None
+    return re.findall(pattern, text, flags=re.DOTALL)