客户端js。带有FileReader和fetch。

const base64 = await fetch('https://i.imgur.com/gBi0yjr.png')
  .then(response => response.blob())
  .then(blob => {
    const reader = new FileReader();
    reader.readAsDataURL(blob);
    return new Promise((res) => {
      reader.onloadend = () => {
      res(reader.result);
    }})
  })

试试这个

import requests
import base64

# Replace this URL with your Firebase Storage URL
image_url = 'https://firebasestorage.googleapis.com/...'

# Fetch the image data from the URL
response = requests.get(image_url)

# Encode the image data as Base64
base64_image = base64.b64encode(response.content).decode('utf-8')

print(base64_image)

给予看：

var request = require('request').defaults({ encoding: null });

request.get(/* URL FIREBASE */, function (error, response, body) {
    if (!error && response.statusCode == 200) {
        data = Buffer.from(body).toString('base64');
        console.log(data);
    }
});