利用LangChain实现网页内容爬取并总结_langchain获取网页数据

背景

利用LangChain中load_summarize_chain实现网页内容爬取并总结。

亮点：

网页内容过长，导致超过LLM的token限制，使用LangChain中load_summarize_chain实现。

Map-reduce思想：

• 先对长文本进行切分
• map阶段-对每段进行summary
• reduce-对每个map再进行总结
• 实现长文本内容总结

案例实现：

背景：想查找某个产品的生产厂商，需要先去网页查找相关连接，然后分别总结每个连接内容，最后对内容进行汇总。以下为代码：

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# 使用google针对产品进行搜索，返回产品列表
 
import os
from autogen import config_list_from_json
import autogen
import requests
from bs4 import BeautifulSoup
import json
 
# from langchain.chat_models import ChatOpenAI
from langchain_community.chat_models import ChatOpenAI
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.chains.summarize import load_summarize_chain
from langchain import PromptTemplate
import openai
from dotenv import load_dotenv
# Get API key
load_dotenv()
config_list3 = {"model": "gpt-3.5-turbo","api_key": "sk-xxxxx", "cache_seed": 42}
 
os.environ["OPENAI_API_KEY"] = "sk-xxxxx"
 
# summary chain:对每个url输出进行总结
def summary(product,content):
    llm = ChatOpenAI(temperature=0, model="gpt-3.5-turbo-16k-0613")
    text_splitter = RecursiveCharacterTextSplitter(
        separators=["\n\n", "\n"], chunk_size=10000, chunk_overlap=500)
    docs = text_splitter.create_documents([content])
    map_prompt = """
        content is :{text}
        Please summarize the Chinese manufacturers of """+ product +""" ,based on the above content and return them in list format.
        The returned results should be in the following format(Return strictly in list format.): ["manu1","manu2","manu3"...]
        The manufacturers should be from the Chinese market, and it's preferred to use the full name of the manufacturers rather than abbreviations.
        """
    combine_prompt = """
        content is :{text}
        Please summarize the Chinese manufacturers of """+ product +""" ,based on the above content and return them in list format.
        The returned results should be in the following format(Return strictly in list format.): ["manu1","manu2","manu3"...]
        The manufacturers should be from the Chinese market, and it's preferred to use the full name of the manufacturers rather than abbreviations.
        """
    map_prompt_template = PromptTemplate(
        template=map_prompt, input_variables=["text"])
    combine_prompt_template = PromptTemplate(
        template=combine_prompt, input_variables=["text"])
 
    summary_chain = load_summarize_chain(
        llm=llm,
        chain_type='map_reduce',
        map_prompt=map_prompt_template,
        combine_prompt=combine_prompt_template,
        verbose=False
    )
 
    output = summary_chain.run(input_documents=docs, )
    # print(output)
    return output
# print(summary("GPU","GPU的生产厂家有：七彩虹厂商,技嘉厂商."))
# print(type(summary("GPU","GPU的生产厂家有：七彩虹厂商,技嘉厂商.")))
 
# 抓取内容：
def scrape(product:str,url: str):
    # scrape and summary
    print("Scraping website...")
    # Define the headers for the request
    headers = {
        'Cache-Control': 'no-cache',
        'Content-Type': 'application/json',
    }
    # Define the data to be sent in the request
    data = {
        "url": url
    }
    # 转json
    data_json = json.dumps(data)
 
    # Send the POST request
    response = requests.post(
        "https://chrome.browserless.io/content?token=2db344e9-a08a-4179-8f48-195a2f7ea6ee", headers=headers, data=data_json)
 
    # Check the response status code
    if response.status_code == 200:
        soup = BeautifulSoup(response.content, "html.parser")
        text = soup.get_text()
        # print("CONTENTTTTTT:", text)
        # 不论长短都做总结  -> 生成厂商list
        # text超长问题
        if len(text) > 8000:
            text = text[:8000]
        output = summary(product,text)
        try:
            result_list = eval(output)
        except Exception as e:
            print("生成结果格式转化为list失败，返回为[]")
            result_list = []
        return result_list
    else:
        print(f"HTTP request failed with status code {response.status_code}")
 
# 查找
def search(query):
    url = "https://google.serper.dev/search"
 
    payload = json.dumps({
        "q": query
    })
    headers = {
        'X-API-KEY': 'do not use mine',
        'Content-Type': 'application/json'
    }
 
    response = requests.request("POST", url, headers=headers, data=payload)
    results = response.json()['organic']
    # print(results)
    product_manu=[]
    for res in results[:10]:
        if res["link"]:
            res_manu = scrape(query, res["link"])
            # 增加判断，如果返回是列表再去扩展
            if isinstance(res_manu, list):
                product_manu.extend(res_manu)
            else:
                print("the result of scrape is not list ,pass ")
        else:
            continue
 
    print("******  product_manu is: \n",product_manu)
    return response.json()
 
search("RTX3050显卡生产厂商")
 
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