基于LangChain自查询检索器的RAG系统开发实战

def get_data(API_key, Movie_ID, max_retries=5):
    """
函数以JSON格式提取感兴趣的电影的详细信息。

    parameters:
    API_key (str): Your API key for TMBD
    Movie_ID (str): TMDB id for film of interest

    returns:
    dict: JSON格式的字典，包含您的电影的所有细节
兴趣
    """

    query = 'https://api.themoviedb.org/3/movie/' + Movie_ID + \
        '?api_key='+API_key + '&append_to_response=keywords,' + \
            'watch/providers,credits'
    for i in range(max_retries):
        response = requests.get(query)
        if response.status_code == 429:
            # If the response was a 429, wait and then try again
            print(
                f"Request limit reached. Waiting and retrying ({i+1}/{
                    max_retries})")
            time.sleep(2 ** i)  # Exponential backoff
        else:
            dict = response.json()
            return dict

credits = dict['credits']
    actor_list, director_list = [], []

# 分析演员表
cast = credits['cast']
NUM_ACTORS = 5
for member in cast[:NUM_ACTORS]:
    actor_list.append(member["name"])

# 分析剧组
crew = credits['crew']
for member in crew:
    if member['job'] == 'Director':
        director_list.append(member["name"])

actor_str = ', '.join(list(set(actor_list)))
director_str = ', '.join(list(set(director_list)))

# 从所有csv文件加载数据
loader = DirectoryLoader(
    path="./data",
    glob="*.csv",
    loader_cls=CSVLoader,
    show_progress=True)

docs = loader.load()

metadata_field_info = [
    AttributeInfo(
        name="Title", description="The title of the movie", type="string"),
    AttributeInfo(name="Runtime (minutes)",
                  description="The runtime of the movie in minutes", type="integer"),
    AttributeInfo(name="Language",
                  description="The language of the movie", type="string"),
    ...
]

for doc in docs:
    #将page_content字符串解析到字典中
    page_content_dict = dict(line.split(": ", 1)
                             for line in doc.page_content.split("\n") if ": " in line)
    
    doc.page_content = 'Overview: ' + page_content_dict.get(
        'Overview') + '. Keywords: ' + page_content_dict.get('Keywords')
    doc.metadata = {field.name: page_content_dict.get(
        field.name) for field in metadata_field_info}

    #将字段从字符串转换为字符串列表
    for field in fields_to_convert_list:
        convert_to_list(doc, field)      

    # 将字段从字符串转换为整数
    for field in fields_to_convert_int:
        convert_to_int(doc, field)

# 如果尚未创建索引，则取消注释
pc.create_index(
    name=PINECONE_INDEX_NAME,
    dimension=1536,
    metric="cosine",
    spec=PodSpec(
        environment="gcp-starter"
    )
)

# 目标索引和检查状态
pc_index = pc.Index(PINECONE_INDEX_NAME)
print(pc_index.describe_index_stats())

embeddings = OpenAIEmbeddings(model='text-embedding-ada-002')

vectorstore = PineconeVectorStore(
    pc_index, embeddings
)

# 创建记录管理器
namespace = f"pinecone/{PINECONE_INDEX_NAME}"
record_manager = SQLRecordManager(
    namespace, db_url="sqlite:///record_manager_cache.sql"
)

record_manager.create_schema()

# 将文档上载到松果网站
index(docs, record_manager, vectorstore,
      cleanup="full", source_id_key="Website")

document_content_description = "Brief overview of a movie, along with keywords"

        # 定义允许的比较器列表
        allowed_comparators = [
            "$eq",  # Equal to (number, string, boolean)
            "$ne",  # Not equal to (number, string, boolean)
            "$gt",  # Greater than (number)
            "$gte",  # Greater than or equal to (number)
            "$lt",  # Less than (number)
            "$lte",  # Less than or equal to (number)
            "$in",  # In array (string or number)
            "$nin",  # Not in array (string or number)
            "$exists", # Has the specified metadata field (boolean)
        ]

        examples = [
            (
                "Recommend some films by Yorgos Lanthimos.",
                {
                    "query": "Yorgos Lanthimos",
                    "filter": 'in("Directors", ["Yorgos Lanthimos]")',
                },
            ),
            (
                "Films similar to Yorgos Lanthmios movies.",
                {
                    "query": "Dark comedy, absurd, Greek Weird Wave",
                    "filter": 'NO_FILTER',
                },
            ),
            ...
        ]

        metadata_field_info = [
            AttributeInfo(
                name="Title", description="The title of the movie", type="string"),
            AttributeInfo(name="Runtime (minutes)",
                          description="The runtime of the movie in minutes", type="integer"),
            AttributeInfo(name="Language",
                          description="The language of the movie", type="string"),
            ...
        ]

        constructor_prompt = get_query_constructor_prompt(
            document_content_description,
            metadata_field_info,
            allowed_comparators=allowed_comparators,
            examples=examples,
        )

        output_parser = StructuredQueryOutputParser.from_components()
        query_constructor = constructor_prompt | query_model | output_parser

        retriever = SelfQueryRetriever(
            query_constructor=query_constructor,
            vectorstore=vectorstore,
            structured_query_translator=PineconeTranslator(),
            search_kwargs={'k': 10}
        )

chat_model = ChatOpenAI(
    model=SUMMARY_MODEL_NAME,
    temperature=0,
    streaming=True,
)

prompt = ChatPromptTemplate.from_messages(
    [
        (
            'system',
            """
            Your goal is to recommend films to users based on their 
            query and the retrieved context. If a retrieved film doesn't seem 
            relevant, omit it from your response. If your context is empty
            or none of the retrieved films are relevant, do not recommend films
            , but instead tell the user you couldn't find any films 
            that match their query. Aim for three to five film recommendations,
            as long as the films are relevant. You cannot recommend more than 
            five films. Your recommendation should be relevant, original, and 
            at least two to three sentences long.
            
            YOU CANNOT RECOMMEND A FILM IF IT DOES NOT APPEAR IN YOUR 
            CONTEXT.

            # TEMPLATE FOR OUTPUT
            - **Title of Film**:
                - Runtime:
                - Release Year:
                - Streaming:
                - (Your reasoning for recommending this film)
            
            Question: {question} 
            Context: {context} 
            """
        ),
    ]
)

def format_docs(docs):
    return "\n\n".join(f"{doc.page_content}\n\nMetadata: {doc.metadata}" for doc in docs)

# Create a chatbot Question & Answer chain from the retriever
rag_chain_from_docs = (
    RunnablePassthrough.assign(
        context=(lambda x: format_docs(x["context"])))
    | prompt
    | chat_model
    | StrOutputParser()
)

rag_chain_with_source = RunnableParallel(
    {"context": retriever, "question": RunnablePassthrough()}
).assign(answer=rag_chain_from_docs)

for chunk in rag_chain_with_source.stream(query):
    for key in chunk:
        if key == 'answer':
            yield chunk[key]