Firebase Cloud Function成功提取数据但无法返回响应求助

问题描述 #

开发Python版Firebase Cloud Function，用于提取指定URL中PDF文件的文本和链接。函数能正确提取数据（日志中可看到打印结果），但返回响应时无法得到预期结果，Postman会持续加载直至超时。

原代码 #

from firebase_functions import https_fn
from firebase_admin import initialize_app

import requests
import fitz  # PyMuPDF
from io import BytesIO

from firebase_functions import https_fn, options
import flask

initialize_app()
app = flask.Flask(__name__)

@app.post("/extract")
def extract():
    """
    Extracts text from a PDF file and returns it as a JSON response.
    """
    # Get the request data
    request_data = flask.request.get_json()
    
    # Check if the request data is valid
    if not request_data or 'url' not in request_data:
        return flask.jsonify({'error': 'Invalid request data'}), 400

    # Get the URL of the PDF file
    pdf_url = request_data['url']

    # Download the PDF file
    response = requests.get(pdf_url)
    pdf_bytes = response.content
    doc = fitz.open(stream=pdf_bytes, filetype="pdf")
    text = ""
    links = []
    for page in doc:
        text = page.get_text()
        print(text)

        links = page.get_links()
        for link in links:
            if link.get('uri'):
                links.append(link['uri'])
            print(link)
    response_data = {
        'text': text,
        'links': links
    }
    print(response_data)
    # Return the extracted text as a JSON response_data
    return flask.jsonify(response_data), 200


@app.route('/__/health', methods=['GET'])
def health_check():
    return "OK", 200

@https_fn.on_request()
def extractor(req: https_fn.Request) -> https_fn.Response:
    with app.request_context(req.environ):
        return app.full_dispatch_request()

问题原因 #

1. 无限循环导致超时：处理每页链接时，将links赋值为当前页的链接列表，接着遍历links时又执行links.append(link['uri'])，不断向列表添加新元素，导致循环永远无法结束，函数卡死引发请求超时。
2. 文本仅保留最后一页：text = page.get_text()每次覆盖之前的文本，最终返回的只有PDF最后一页的内容，而非全部页面文本。

解决方案 #

修改链接处理逻辑，分离当前页链接列表与URI存储列表，避免无限循环；同时修改文本拼接方式，累加所有页面文本：

from firebase_functions import https_fn
from firebase_admin import initialize_app

import requests
import fitz  # PyMuPDF
from io import BytesIO

from firebase_functions import https_fn, options
import flask

initialize_app()
app = flask.Flask(__name__)

@app.post("/extract")
def extract():
    """
    Extracts text from a PDF file and returns it as a JSON response.
    """
    # Get the request data
    request_data = flask.request.get_json()
    
    # Check if the request data is valid
    if not request_data or 'url' not in request_data:
        return flask.jsonify({'error': 'Invalid request data'}), 400

    # Get the URL of the PDF file
    pdf_url = request_data['url']

    # Download the PDF file
    response = requests.get(pdf_url)
    pdf_bytes = response.content
    doc = fitz.open(stream=pdf_bytes, filetype="pdf")
    text = ""
    links = []
    for page in doc:
        # 累加所有页面的文本
        text += page.get_text()
        print(text)

        # 单独存储当前页的链接列表，避免修改遍历的列表
        page_links = page.get_links()
        for link in page_links:
            if link.get('uri'):
                links.append(link['uri'])
            print(link)
    response_data = {
        'text': text,
        'links': links
    }
    print(response_data)
    # Return the extracted text as a JSON response_data
    return flask.jsonify(response_data), 200


@app.route('/__/health', methods=['GET'])
def health_check():
    return "OK", 200

@https_fn.on_request()
def extractor(req: https_fn.Request) -> https_fn.Response:
    with app.request_context(req.environ):
        return app.full_dispatch_request()

说明 #

• 用page_links单独存储当前页的原始链接数据，遍历该列表时向全局links添加URI，彻底避免无限循环。
• 文本使用text += page.get_text()实现累加，确保返回PDF所有页面的完整文本。

内容的提问来源于stack exchange，提问作者sona ali