rag-search-engine / cli /lib /query_enhancement.py
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import os
import time
import json
from dotenv import load_dotenv
from google import genai
from lib.config import GEMINI_MODEL
from sentence_transformers import CrossEncoder
def enhance_query_spell(query: str) -> str:
"""Use Gemini to fix spelling errors in a query"""
# Load API key
load_dotenv()
api_key = os.environ.get("GEMINI_API_KEY")
if not api_key:
raise ValueError("GEMINI_API_KEY not found in environment")
# Create Gemini client
client = genai.Client(api_key=api_key)
# System prompt for spell correction
prompt = f"""Fix any spelling errors in this movie search query.
Only correct obvious typos. Don't change correctly spelled words.
Query: "{query}"
If no errors, return the original query.
Corrected:"""
# Get response from Gemini
response = client.models.generate_content(
model=GEMINI_MODEL,
contents=prompt
)
# Extract and clean the corrected query
corrected = response.text.strip()
# Remove quotes if Gemini added them
if corrected.startswith('"') and corrected.endswith('"'):
corrected = corrected[1:-1]
if corrected.startswith("'") and corrected.endswith("'"):
corrected = corrected[1:-1]
return corrected
def enhance_query_rewrite(query: str) -> str:
"""Use Gemini to rewrite a vague query to be more specific and searchable"""
# Load API key
load_dotenv()
api_key = os.environ.get("GEMINI_API_KEY")
if not api_key:
raise ValueError("GEMINI_API_KEY not found in environment")
# Create Gemini client
client = genai.Client(api_key=api_key)
# System prompt for query rewriting
prompt = f"""Rewrite this movie search query to be more specific and searchable.
Original: "{query}"
Consider:
- Common movie knowledge (famous actors, popular films)
- Genre conventions (horror = scary, animation = cartoon)
- Keep it concise (under 10 words)
- It should be a google style search query that's very specific
- Don't use boolean logic
Examples:
- "that bear movie where leo gets attacked" -> "The Revenant Leonardo DiCaprio bear attack"
- "movie about bear in london with marmalade" -> "Paddington London marmalade"
- "scary movie with bear from few years ago" -> "bear horror movie 2015-2020"
Rewritten query:"""
# Get response from Gemini
response = client.models.generate_content(
model=GEMINI_MODEL,
contents=prompt
)
# Extract and clean the rewritten query
rewritten = response.text.strip()
# Remove quotes if Gemini added them
if rewritten.startswith('"') and rewritten.endswith('"'):
rewritten = rewritten[1:-1]
if rewritten.startswith("'") and rewritten.endswith("'"):
rewritten = rewritten[1:-1]
return rewritten
def enhance_query_expand(query: str) -> str:
"""Use Gemini to expand a query with related terms and synonyms"""
# Load API key
load_dotenv()
api_key = os.environ.get("GEMINI_API_KEY")
if not api_key:
raise ValueError("GEMINI_API_KEY not found in environment")
# Create Gemini client
client = genai.Client(api_key=api_key)
# System prompt for query expansion
prompt = f"""Expand this movie search query with related terms.
Add synonyms and related concepts that might appear in movie descriptions.
Keep expansions relevant and focused.
This will be appended to the original query.
Examples:
- "scary bear movie" -> "scary horror grizzly bear movie terrifying film"
- "action movie with bear" -> "action thriller bear chase fight adventure"
- "comedy with bear" -> "comedy funny bear humor lighthearted"
Query: "{query}"
"""
# Get response from Gemini
response = client.models.generate_content(
model=GEMINI_MODEL,
contents=prompt
)
# Extract and clean the expanded query
expanded = response.text.strip()
# Remove quotes if Gemini added them
if expanded.startswith('"') and expanded.endswith('"'):
expanded = expanded[1:-1]
if expanded.startswith("'") and expanded.endswith("'"):
expanded = expanded[1:-1]
return expanded
def rerank_individual(query: str, results: list[dict]) -> list[dict]:
"""Use Gemini to individually re-rank each result"""
# Load API key
load_dotenv()
api_key = os.environ.get("GEMINI_API_KEY")
if not api_key:
raise ValueError("GEMINI_API_KEY not found in environment")
# Create Gemini client
client = genai.Client(api_key=api_key)
reranked_results = []
for result in results:
# System prompt for re-ranking
prompt = f"""Rate how well this movie matches the search query.
Query: "{query}"
Movie: {result.get("title", "")} - {result.get("document", "")}
Consider:
- Direct relevance to query
- User intent (what they're looking for)
- Content appropriateness
Rate 0-10 (10 = perfect match).
Give me ONLY the number in your response, no other text or explanation.
Score:"""
try:
# Get response from Gemini
response = client.models.generate_content(
model=GEMINI_MODEL,
contents=prompt
)
# Extract score
score_text = response.text.strip()
# Try to parse the score
try:
rerank_score = float(score_text)
except ValueError:
# If parsing fails, try to extract first number
import re
numbers = re.findall(r'\d+\.?\d*', score_text)
rerank_score = float(numbers[0]) if numbers else 5.0
# Add rerank score to result
result['rerank_score'] = rerank_score
reranked_results.append(result)
# Sleep to avoid rate limits
time.sleep(3)
except Exception as e:
print(f"Warning: Failed to rerank {result.get('title', 'Unknown')}: {e}")
result['rerank_score'] = 5.0 # Default score on error
reranked_results.append(result)
# Sort by rerank score (descending)
reranked_results.sort(key=lambda x: x['rerank_score'], reverse=True)
return reranked_results
def rerank_batch(query: str, results: list[dict]) -> list[dict]:
"""Use Gemini to batch re-rank all results in one call"""
# Load API key
load_dotenv()
api_key = os.environ.get("GEMINI_API_KEY")
if not api_key:
raise ValueError("GEMINI_API_KEY not found in environment")
# Create Gemini client
client = genai.Client(api_key=api_key)
# Build the document list string
doc_list_str = ""
for idx, result in enumerate(results):
doc_list_str += f"{result['id']}. {result['title']} - {result.get('document', '')[:200]}...\n"
# System prompt for batch re-ranking
prompt = f"""Rank these movies by relevance to the search query.
Query: "{query}"
Movies:
{doc_list_str}
Return ONLY the IDs in order of relevance (best match first). Return a valid JSON list, nothing else. For example:
[75, 12, 34, 2, 1]
"""
try:
# Get response from Gemini
response = client.models.generate_content(
model=GEMINI_MODEL,
contents=prompt
)
# Extract and parse JSON response
response_text = response.text.strip()
# Clean up response if needed (remove markdown code blocks)
if response_text.startswith("```"):
# Remove ```json or ``` prefix and suffix
lines = response_text.split('\n')
response_text = '\n'.join(lines[1:-1]) if len(lines) > 2 else response_text
# Parse JSON
ranked_ids = json.loads(response_text)
# Create a mapping of ID to result
id_to_result = {result['id']: result for result in results}
# Reorder results based on ranked IDs
reranked_results = []
for rank, doc_id in enumerate(ranked_ids, 1):
if doc_id in id_to_result:
result = id_to_result[doc_id]
result['rerank_rank'] = rank
reranked_results.append(result)
# Add any results that weren't ranked (at the end)
ranked_id_set = set(ranked_ids)
for result in results:
if result['id'] not in ranked_id_set:
result['rerank_rank'] = len(reranked_results) + 1
reranked_results.append(result)
return reranked_results
except Exception as e:
print(f"Warning: Batch reranking failed: {e}")
print(f"Response was: {response_text if 'response_text' in locals() else 'No response'}")
# Return original order with default ranks
for rank, result in enumerate(results, 1):
result['rerank_rank'] = rank
return results
def rerank_cross_encoder(query: str, results: list[dict]) -> list[dict]:
"""Use a cross-encoder model to re-rank results"""
# Create pairs of [query, document]
pairs = []
for result in results:
doc_text = f"{result.get('title', '')} - {result.get('document', '')}"
pairs.append([query, doc_text])
# Initialize cross-encoder model (does this once per query)
cross_encoder = CrossEncoder("cross-encoder/ms-marco-TinyBERT-L-2-v2")
# Compute scores for all pairs
scores = cross_encoder.predict(pairs)
# Add scores to results
for i, result in enumerate(results):
result['cross_encoder_score'] = float(scores[i])
# Sort by cross-encoder score (descending)
results.sort(key=lambda x: x['cross_encoder_score'], reverse=True)
return results
def evaluate_results(query: str, results: list[dict]) -> list[int]:
"""Use Gemini to evaluate search result relevance"""
# Load API key
load_dotenv()
api_key = os.environ.get("GEMINI_API_KEY")
if not api_key:
raise ValueError("GEMINI_API_KEY not found in environment")
# Create Gemini client
client = genai.Client(api_key=api_key)
# Format results for the prompt
formatted_results = []
for i, result in enumerate(results, 1):
formatted_results.append(f"{i}. {result['title']} - {result.get('document', '')[:200]}")
# System prompt for evaluation
prompt = f"""Rate how relevant each result is to this query on a 0-3 scale:
Query: "{query}"
Results:
{chr(10).join(formatted_results)}
Scale:
- 3: Highly relevant
- 2: Relevant
- 1: Marginally relevant
- 0: Not relevant
Do NOT give any numbers out than 0, 1, 2, or 3.
Return ONLY the scores in the same order you were given the documents. Return a valid JSON list, nothing else. For example:
[2, 0, 3, 2, 0, 1]"""
try:
# Get response from Gemini
response = client.models.generate_content(
model=GEMINI_MODEL,
contents=prompt
)
# Extract and parse JSON response
response_text = response.text.strip()
# Clean up response if needed (remove markdown code blocks)
if response_text.startswith("```"):
# Remove ```json or ``` prefix and suffix
lines = response_text.split('\n')
response_text = '\n'.join(lines[1:-1]) if len(lines) > 2 else response_text
# Parse JSON
scores = json.loads(response_text)
# Validate scores are 0-3
scores = [max(0, min(3, int(score))) for score in scores]
return scores
except Exception as e:
print(f"Warning: Evaluation failed: {e}")
print(f"Response was: {response_text if 'response_text' in locals() else 'No response'}")
# Return default scores (all 2s - "relevant")
return [2 for _ in results]