baby mock json endpoint server and cloning endpoints

My boss thought it strange that we didn't already have a "mock server" so that we could keep doing UI work in case the endpoints went down.

He suggested using json-server but that wasn't made to emulate a rich set of endpoints, just one level deep, either GETing all the entries or just one at a time by id. Luckily that kind of server is the easy part of the assignment.

The first part was to make a file "urls.txt", with just the relevant part of the endpoint...

then this script load-db.js hits each of those entries and writes the content to a file in mocks/

const express = require("express");

const fs = require("fs");

const path = require("path");

const app = express();

// Ensure the mocks directory exists

const mocksDir = path.join(__dirname, "mocks");

if (!fs.existsSync(mocksDir)) {

fs.mkdirSync(mocksDir);

}

// Read the command line argument for the prefix

const prefix = process.argv[2];

// Read the URLs from urls.txt

const urlsFilePath = path.join(__dirname, "urls.txt");

const urls = fs.readFileSync(urlsFilePath, "utf8").split("\n");

// Function to make a safe filename from a URL path and append .json

const makeSafeFilename = (urlPath) => encodeURIComponent(urlPath.replace(/^\//, "").replace(/\//g, "_")) + ".json";

// Fetch content and save it as JSON

urls.forEach(async (urlPath) => {

if (!urlPath.trim()) return; // Skip empty lines

const content = await fetch(`${prefix}${urlPath}`).then((res) => res.json());

const safeFilename = makeSafeFilename(urlPath);

fs.writeFileSync(path.join(mocksDir, safeFilename), JSON.stringify(content, null, 2));

console.log(`Saved content from ${urlPath} to ${safeFilename}`);

});

Then the server.js just looks like this:

const express = require("express");

const fs = require("fs");

const path = require("path");

const cors = require("cors");

const app = express();

app.use(cors());

const mocksDir = path.join(__dirname, "mocks");

app.get("/", (req, res) => {

fs.readdir(mocksDir, (err, files) => {

if (err) {

console.error(err);

return res.status(500).send("Server error");

}

const links = files

.filter((file) => file.endsWith(".geojson") || file.endsWith(".json"))

.map((file) => {

const decodedFilename = file.replace(/\..+$/, "").replace(/_/g, "/");

const encodedPath = decodedFilename

.split("/")

.map((part) => encodeURIComponent(part))

.join("/");

return `<li><a href="/${encodedPath}">${file}</a></li>`;

})

.join("");

res.send(`<ul>${links}</ul>`);

});

});

app.get("*", (req, res) => {

const safeFilename = encodeURIComponent(req.path.replace(/^\//, "").replace(/\//g, "_"));

const filePath = path.join(mocksDir, safeFilename);

if (fs.existsSync(`${filePath}.geojson`) || fs.existsSync(`${filePath}.json`)) {

res.type("application/json");

res.sendFile(fs.existsSync(`${filePath}.geojson`) ? `${filePath}.geojson` : `${filePath}.json`);

console.log(req.path);

} else {

res.status(404).send("Not Found");

console.error(`404 ${req.path}`);

}

});

// Use environment variable for port or a default value

const port = process.env.PORT || 3000;

app.listen(port, () => {

console.log(`Mock server listening at http://localhost:${port}`);

});

package.json is

{

"name": "mock-server",

"version": "1.0.0",

"description": "",

"main": "index.js",

"scripts": {

"start": "node server.js"

},

"keywords": [],

"author": "",

"license": "ISC",

"dependencies": {

"cors": "^2.8.5",

"express": "^4.18.3",

"node-fetch": "^3.3.2"

}

}

(Sigh, I suppose if I was feeling ambitious I should make my a little project out of this and put it on github, but I'm sure someone has, and better.)

UPDATE: this version now lists the endpoint/files it knows about if you go to the root, and listens to process.env.PORT for instructions on port