@techdocs/cli/dist/lib/livereload.cjs.js

Utility CLI for managing TechDocs sites in Backstage.

'use strict';

var httpProxy = require('http-proxy');

function _interopDefaultCompat (e) { return e && typeof e === 'object' && 'default' in e ? e : { default: e }; }

var httpProxy__default = /*#__PURE__*/_interopDefaultCompat(httpProxy);

const LIVE_RELOAD_ELEMENT = "live-reload";
const LIVE_RELOAD_ATTR_EPOCH = "live-reload-epoch";
const LIVE_RELOAD_ATTR_REQUEST_ID = "live-reload-request-id";
const CLI_LIVERELOAD_PATH = "/.livereload";
const MKDOCS_LIVERELOAD_PATH = "/livereload";
const CONTENT_TYPE_HTML = "text/html";
const HEADER_CONTENT_LENGTH = "content-length";
const BODY_START_RE = /<body\b[^>]*>/;
const MKDOCS_LIVERELOAD_CALL_RE = /livereload\(\s*(\d+)\s*,\s*(\d+)\s*\)\s*;?/;
function injectLivereloadParameters(html) {
  const livereloadMatch = html.match(MKDOCS_LIVERELOAD_CALL_RE);
  if (!livereloadMatch) {
    return html;
  }
  const [, epoch, requestId] = livereloadMatch;
  const liveReloadTag = `<${LIVE_RELOAD_ELEMENT} ${LIVE_RELOAD_ATTR_EPOCH}="${epoch}" ${LIVE_RELOAD_ATTR_REQUEST_ID}="${requestId}"></${LIVE_RELOAD_ELEMENT}>`;
  const bodyStart = html.match(BODY_START_RE);
  const bodyStartIndex = bodyStart?.index ?? 0;
  const bodyStartLength = bodyStart?.[0]?.length ?? 0;
  if (bodyStartIndex === 0 || bodyStartLength === 0) {
    return html;
  }
  const bodyEndIndex = bodyStartIndex + bodyStartLength;
  return html.slice(0, bodyEndIndex) + liveReloadTag + html.slice(bodyEndIndex);
}
function setCorsHeaders(response) {
  response.setHeader("Access-Control-Allow-Origin", "*");
  response.setHeader("Access-Control-Allow-Methods", "GET, OPTIONS");
}
function proxyHtmlWithLivereloadInjection(options) {
  const { request, response, mkdocsTargetAddress, proxyEndpoint, onError } = options;
  const htmlProxy = httpProxy__default.default.createProxyServer({
    target: mkdocsTargetAddress,
    selfHandleResponse: true
  });
  htmlProxy.on("error", onError);
  htmlProxy.on("proxyRes", (proxyRes, _req, res) => {
    const contentType = proxyRes.headers["content-type"];
    const contentEncoding = proxyRes.headers["content-encoding"];
    const isHtml = contentType && typeof contentType === "string" && contentType.startsWith(CONTENT_TYPE_HTML);
    if (isHtml && !contentEncoding) {
      const chunks = [];
      proxyRes.on("data", (chunk) => {
        chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
      });
      proxyRes.on("end", () => {
        const body = Buffer.concat(chunks).toString("utf8");
        const modifiedHtml = injectLivereloadParameters(body);
        res.statusCode = proxyRes.statusCode ?? 200;
        Object.keys(proxyRes.headers).forEach((key) => {
          if (key.toLowerCase() !== HEADER_CONTENT_LENGTH) {
            res.setHeader(key, proxyRes.headers[key]);
          }
        });
        setCorsHeaders(res);
        res.end(modifiedHtml);
      });
    } else {
      res.statusCode = proxyRes.statusCode ?? 200;
      Object.keys(proxyRes.headers).forEach((key) => {
        res.setHeader(key, proxyRes.headers[key]);
      });
      setCorsHeaders(res);
      proxyRes.pipe(res);
    }
  });
  const forwardPath = request.url?.replace(new RegExp(`^${proxyEndpoint}`, "i"), "") || "";
  request.url = forwardPath;
  htmlProxy.web(request, response);
}
function proxyMkdocsLivereload(options) {
  const { request, response, mkdocsTargetAddress, onError } = options;
  const proxy = httpProxy__default.default.createProxyServer({ target: mkdocsTargetAddress });
  proxy.on("error", onError);
  setCorsHeaders(response);
  response.setHeader("Access-Control-Allow-Headers", "Content-Type");
  request.url = request.url?.replace(
    CLI_LIVERELOAD_PATH,
    MKDOCS_LIVERELOAD_PATH
  );
  proxy.web(request, response);
}

exports.injectLivereloadParameters = injectLivereloadParameters;
exports.proxyHtmlWithLivereloadInjection = proxyHtmlWithLivereloadInjection;
exports.proxyMkdocsLivereload = proxyMkdocsLivereload;
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