Work around Wiremock not supporting server send events (SSE) when recording HTTP traffic. This proxy will sit between Wiremock and target and close the connection proactively from the client side.

index.js

// Proxy that will close any connection for a response with the partial payload "event: end"
// This allows us to treat server send events (SSE) as if the server would close the connection, easing integration with regular HTTP tools
const http = require("http"),
  httpProxy = require("http-proxy"),
  zlib = require("zlib");

const target = process.env.TARGET_BASE_URL || "http://localhost:8000",
  port = process.env.PORT || 3333;

const proxy = httpProxy.createProxyServer({});

proxy.on("proxyReq", function (proxyReq, req, res, options) {
  // Is it wiremock that adds this header? Let's keep it plain text
  proxyReq.setHeader("Accept-Encoding", "");
});

proxy.on("proxyRes", function (proxyRes, req, res) {
  proxyRes.on("data", (d) => {
    if (/event: end/.test(d.toString())) {
      setTimeout(() => res.end(), 10);
    }
  });
});

console.log("Opening on connection", port, "proxying", target);
http
  .createServer(function (req, res) {
    proxy.web(req, res, { target });
  })
  .listen(port);