@bonniernews/local-esi

Local-ESI

Make your Express app work like it had Akamai Edge Side Includes parsing or just stream your ESI decorated markup to the parser.

API

• localEsi(html, req, res, next)
• localEsi.createStream(req)
• localEsi.createParser(req)
• localEsi.htmlWriter()

localEsi(html, req, res, next)

Use as an expressjs request callback function.

Arguments:

• html: string with markup
• req: request with headers and cookies
• res: response with send, redirect, set, and status function
• next: function to catch occasional error in

"use strict";

const localEsi = require("@bonniernews/local-esi");

module.exports = (req, res, next) => {
  res.render("index", { data: "a" }, (err, html) => {
    if (err) return next(err);

    localEsi(html, req, res, next);
  });
};

localEsi.createStream(req)

Create pipable ESI parse as stream. Emits events.

Arguments:

• req: request with headers and cookies

Returns markup stream.

"use strict";

const {createStream} = require("@bonniernews/local-esi");

module.exports = (req, res, next) => {
  const esiParseStream = createStream(req)
    .on("add_header", (name, value) => res.set(name, value))
    .once("set_redirect", (statusCode, location) => res.redirect(statusCode, location));

  res.render("index")
    .pipe(esiParseStream)
    .on("error", next);
};

localEsi.createParser(req)

Create ESI parse transform stream. Emits events.

Arguments:

• req: request with headers and cookies

Requires markup stream to read from. Writes object stream.

"use strict";

const HtmlParser = require("@bonniernews/atlas-html-stream");
const {createParser: createESIParser, htmlWriter} = require("@bonniernews/local-esi");

module.exports = function channelRendering(req, res, next) {
  const esiParser = createESIParser(req)
    .once("set_redirect", (statusCode, location) => {
      res.status(statusCode).redirect(location);
    })
    .on("set_response_code", (statusCode, body) => {
      res.status(statusCode);
      if (body) res.send(body);
    })
    .on("add_header", (name, value) => {
      res.set(name, value);
    });

  return res.render("index")
    .pipe(new HtmlParser({preserveWS: true}))
    .pipe(esiParser)
    .pipe(htmlWriter())
    .pipe(res)
    .once("error", (err) => {
      next(err);
    });
};

localEsi.htmlWriter()

Returns transform object stream to markup buffer stream.

ESI Parsing Events

ESI instructions are emitted as events.

set_response_code

Set status code and optional body.

add_header

Set header name and value.

set_redirect

Redirect with status code and location.

Markup object stream

Object streams requires the schema {name, data, text} representing tag name, tag attributes, and text. This project uses atlas-html-stream for html parsing.