Python3.8.5 使用 http 请求将文件从一个 docker 容器发送到另一个容器的问题

Question

I have a problem with my python(python3.8.5) project. I have two docker containers. One is used for the frontend(container2) using flask. There I have a website where I can send requests(package requests) to the second container(backend). In the backend(container1) I have to create a zip file containing multiple file. That part is done. Now the problem is how can I get this file to the frontend(container2) and from there I need to download it via the website.

So I need a solution to send a http request (now I have requests.get(URL to backend)) from the frontend to the backend. In the response I need the zip file which I can download then from the website.

I googled already many hours but I cannot find a good solution. I thing it would be good if I don't have to store the zip file on the frontend and on the backend. If possible I would like to have it stored just on the backend and send it to the frontend and directly download it.

I hope you understand my problem and can help me. Br

Answer 1

A probably incomplete solution, that does what you describe. Depending on other concerns (like file size) this might not be what you really want, but it works.

As an example I have 2 flask servers: flask1 (backend) and flask2 (frontend):

flask1:

from flask import Flask, send_file, request

app = Flask(__name__)

@app.route('/get_file')
def get_image():
    return send_file(request.args.get('name'))

flask2:

from flask import Flask, send_file, request

import io
import requests

app = Flask(__name__)

@app.route('/get_something')
def get_image():
    r = requests.get("http://localhost:5000/get_file?name="+request.args.get('name'))
    return  send_file(io.BytesIO(r.content), mimetype=r.headers['Content-Type'],
                      as_attachment=True, attachment_filename="file")

To test you can run them on different ports, like:

FLASK_APP=flask1.py flask run --port=5000
FLASK_APP=flask2.py flask run --port=8080

Then if you go to the browser and access the frontend with an URL like:

http://localhost:8080/get_something?name=download.png

the frontend will "pass" the request to the backend, then re-send what it receives, hence returning the file.

Things that code above does not address: file naming and errors.

Answer 2

You could proxy the request from frontend. I assume you use something like react. So if you add a line like:

"proxy": "http://backend-container:8080"

to your package.json, frontend should proxy to the backend. Now you can send requests like http://front-end/api/hello and it will hit the backend. Not sure if it is the best solution but might work.

examples:

https://create-react-app.dev/docs/proxying-api-requests-in-development/
https://medium.com/bb-tutorials-and-thoughts/react-how-to-proxy-to-backend-server-5588a9e0347
https://www.twilio.com/blog/react-app-with-node-js-server-proxy