how to make http-proxy-middleware connect to localhost server from create-react-app

Question

How do connect to multiple APIs with React App?

Create-react-app with Express backend, using http-proxy-middleware.

Demo bug : https://github.com/svgpubs/nodeproxy.git

I am using http-proxy-middleware to try to connect a demo React App to two different servers: one external website https://api.coingecko.com/api/ and one internal site http://localhost:3001/

It works for the external website. However, localhost:3001 connection doesn't work.

I can connect to the localhost:3001 if I don't use http-proxy-middleware (by adding 'proxy: 'http://localhost:3001'" in package.json) - however, then I can only have one proxy.

Here is the app running: as you can see, there is no response from localhost:3001

Errors: I've tried so many different variations. I either get a cors block from the browser, or the localhost api returns index.html file from public/index.html - resulting in a json parsing error in the browser. On the server, depending on the exact route for localhost endpoint, I sometimes get 50+ lines of this error: Error occurred while trying to proxy request /localhostapi/users from localhost:3001 to http://localhost:3001/ (ECONNRESET) (https://nodejs.org/api/errors.html#errors_common_system_errors)

How do I setup the server and proxy so that App.js can connect to both localhost:3001 routes AND external APIs?

Here is my App.js

import React, { useEffect, useState } from "react";
import "./App.css";

function App() {
  const [externalServerResponse, setExternalServerResponse] = useState(
    "no response"
  );
  const [localhostServerResponse, setLocalhostServerResponse] = useState(
    "no response"
  );

  const getExternalAPI = async () => {
    console.log("calling external api from client");
    const result = await fetch("http://localhost:3001/api_to_external_website");
    console.log("result", result);
    const data = await result.json();
    console.log("data", data);
    setExternalServerResponse(JSON.stringify(data[0]));
  };

  const getLocalHostAPI = async () => {
    console.log("calling localhost api from client");
    const result = await fetch("/localhostapi"); //I've tried many syntax variations 
    console.log("result", result);
    const data = await result.json();
    console.log("data", data);
    setLocalhostServerResponse(JSON.stringify(data));
  };

  useEffect(() => {
    getExternalAPI();
    getLocalHostAPI();
  }, []);

  return (
    <div className="App">
      <div style={{ marginTop: "3em", marginBottom: "1em" }}>
        <h2>
          Response from{" "}
          <code>
            <i>www.api.coingecko.com/api</i>
          </code>
          :
        </h2>
      </div>
      <div>{externalServerResponse}</div>
      <div style={{ marginTop: "3em", marginBottom: "1em" }}>
        <h2>
          Response from{" "}
          <code>
            <i>localhost:3001</i>
          </code>{" "}
          :{" "}
        </h2>
      </div>
      <div>{localhostServerResponse}</div>
    </div>
  );
}

export default App;

Here is server.js

const express = require("express");
const { createProxyMiddleware } = require("http-proxy-middleware");
const port = 3001;

const app = express();

app.use(
  "/api_to_external_website",
  createProxyMiddleware({
    target:
      "https://api.coingecko.com/api/v3/coins/markets?vs_currency=USD&order=market_cap_desc&per_page=100&page=1&sparkline=false",
    headers: {
      accept: "application/json",
      method: "GET",
    },
    changeOrigin: true,
  })
);

app.use(
  "/localhostapi",
  createProxyMiddleware({
    target: `http://localhost:${port}/`,
    headers: {
      accept: "application/json",
      method: "GET",
    },
    changeOrigin: true,
  })
);

app.get("/", (req, res) => {
  console.log("localhost:3001 api is running");
  const data = { result: `Success! from localhostapi on localhost:${port}!!` };
  res.send(JSON.parse(data));
});

app.listen(port, function () {
  console.log(`server running now.. ${port}`);
});

How do I set up my server and proxy so that my App.js can get both localhost:3001 routes AND external APIs?

Instructions to run app:

In one terminal: make a folder, clone nodeproxy app, install dependencies, then run server

mkdir newfolder
cd newfolder
git clone https://github.com/svgpubs/nodeproxy.git
npm install
node server.js

Then, keeping the first terminal running, open a second terminal window: go to that same folder and start the react app.

cd newfolder
npm start 

List of things I've tried:

1. Using additional package.json attribute "proxy: 'localhost:3001'

2. src/setupProxy.js

const { createProxyMiddleware } = require("http-proxy-middleware");

module.exports = function(app) {
app.use(
  "/localhostapi",
  createProxyMiddleware({
    target: `http://localhost:${port}/`,
    headers: {
      accept: "application/json",
      method: "GET",
    },
    changeOrigin: true,
  })
);
}

3. changing fetch and app.use syntax

[![enter image description here][3]][3]

Answer 1

I figured out that changing my project folder structure did the trick. Not only can I connect to external website APIs, as above, but I can connect to two+ different ports on my localhost as shown here.

What I think the problem was: My server.js file was in the same directory as the front-end package.json file, which contained the http-proxy-middleware dependency.

Here is the app code on github https://github.com/svgpubs/react-with-multi-apis

This was my incorrect folder structure:

.
├── package.json
├── node_modules
├── public
├── server.js
└── src
    ├── App.css
    ├── App.js
    ├── App.test.js
    ├── index.css
    ├── index.js
    ├── logo.svg
    ├── serviceWorker.js
    ├── setupProxy.js
    └── setupTests.js

The remote api server.js file(s) should not be in the same folder as front-end package.json with http-proxy-middleware listed as dependency. (It might have been that the proxy was attempting to proxy the server to itself. But I might be wrong.)

I rearranged the project to have this structure - which works:

.
├── api1
│   ├── package.json 
|   ├── node_modules
│   └── server1.js
├── api2
│   ├── package.json
|   ├── node_modules
│   └── server2.js
└── reactapp
    ├── node_modules
    ├── package.json
    ├── package-lock.json
    ├── public 
    └── src
        ├── App.css
        ├── App.js
        ├── App.test.js
        ├── index.css
        ├── index.js
        ├── logo.svg
        ├── serviceWorker.js
        ├── setupProxy.js
        └── setupTests.js

setupProxy.js

const { createProxyMiddleware } = require("http-proxy-middleware");

module.exports = function (app) {
  app.use(
    "/api1",
    createProxyMiddleware({
      target: "http://localhost:3080",
      changeOrigin: true,
    })
  );
  app.use(
    "/api2",
    createProxyMiddleware({
      target: "http://localhost:3070",
      changeOrigin: true,
    })
  );
  app.use(
    "/api_to_external_website",
    createProxyMiddleware({
      target:
        "https://api.coingecko.com/api/v3/coins/markets?vs_currency=USD&order=market_cap_desc&per_page=100&page=1&sparkline=false",
      headers: {
        accept: "application/json",
        method: "GET",
      },
      changeOrigin: true,
    })
  );
};

api1/server1.js

const express = require("express");
const bodyParser = require("body-parser");
const port = 3080;
const app = express();
app.use(bodyParser.urlencoded({ extended: false }));

app.get("/api1", (req, res) => {
  console.log(`localhost:${port} api is running`);
  const data = {
    result: `Success! from localhost on localhost:${port}!!`,
  };
  res.send(data);
});

app.listen(port, function () {
  console.log(`server running now.. ${port}`);
});

api2/server.js is identical execpt for port is 3070, and api1/ is api2/