Library-simplified-webpub-viewer NPM

webpub-viewer

A viewer application for web publications, based on Hadrien Gardeur’s proof of concept.

Quickstart

Clone this repo, cd the directory, checkout the master then

npm install

This should run the npm run build script as well, transpiling the TS and SASS files into the dist and viewer folders.

You can run automated tests with

npm test

and transpile at any time with

npm run build

Examples

Examples demonstrate how this webpub-viewer can be used:

with static assets i.e. exploded EPUB files on a server;
with assets served by r2-streamer-js (in-memory model);
embedded in exploded EPUB files themselves.

Example EPUBs The Call of the Wild and A Journey to the Centre of the Earth have been kindly offered by Jellybooks.

Static

The examples/static folder contains the webpub-viewer (viewer folder), two example files (TheCallOfTheWild and AJourneyToTheCentreOfTheEarth folders), and a static-server.js script running a local server using Node.js + Express.

This example runs on https so you’ll need to trust the provided webpubViewer.pem self-signed certificate that node and express use to create an https server.

Re-generating a self-signed certificate

From the repository’s root, the following command has been used on MacOS to create the certificate for localhost:

openssl req -newkey rsa:4096 -x509 -nodes -keyout webpubViewer.pem -new -out webpubViewer.pem -subj /CN=localhost -reqexts SAN -extensions SAN -config <(cat /System/Library/OpenSSL/openssl.cnf <(printf '[SAN]\nsubjectAltName=DNS:localhost')) -sha256 -days 3650

The one provided should run until October 24, 2028.

What’s important is that the cert must have CN=localhost and subjectAltName=DNS:localhost for Chrome. Versions > 58 indeed require a subjectAltName with the proper DNS and/or IP entry/entries.

Trusting self-signed certificates

In order to make the self-signed certificate trusted you need to accept it as a valid certificate on your machine. Doing this will replace red warning (“Unsecured”) notices with a green lock, fully replicating a https/SSL website on localhost for testing. This depends on your platform:

You might need to make it an exception in your web browser so that it can be trusted though (Firefox, Safari, etc.).

Usage

Launch the webpub-viewer with npm run static
Your terminal should display Express server listening on port 3333 – note it’s also listening to errors so will log them in your terminal as well
open https://localhost:3333 in the browser
To stop the server, type ctrl + c

Both examples are available on the same origin, as cross-origin will be restricted by browsers and throw an error in the viewer.

For the origin to be considered the same, protocol (http/https), host and port must be the same. See web browsers’ same-origin policy.

Streamed

In this example, assets are served by the r2-streamer-js (in-memory model). This iteration of webpub-viewer is labelled as "Reader NYPL".

This example runs on http to get around Service Workers issues across all available readers so you don’t need to do anything.

Usage

Start the server with npm run streamed
Your terminal should display Express server listening on port 4444 – note it’s also listening to errors so will log them in your terminal as well
Open http://localhost:4444 in the browser
Enter a link to a remote Epub URL.
To stop the server, type ctrl + c

Embedded

The examples/embedded folder contains an example file (alice folder), in which the webpub-viewer is embedded, and an embedded-server.js script running a local server using Node.js + Express.

This example runs on https but is using the same certificate as the static example.

Usage

Launch the webpub-viewer with npm run embedded
Your terminal should display Express server listening on port 1865 – note it’s also listening to errors so will log them in your terminal as well
open https://localhost:1865 in the browser
To stop the server, type ctrl + c

Testing

Unit testing

By running:

npm test

You’ll launch 200+ automated tests to make sure everything is OK.

Visual Regression Testing

We are also using backstopJS to test for visual regressions. It can indeed help catch issues with user settings and/or features that would be a lot more difficult to catch in unit testing.

It is preferrable you install backstopjs globally as it is a massive download, and is meant as a command that can be used with different projects – note that if installed locally, it will be tied to npm scripts.

npm install -g backstopjs

Since those tests are relying on Pupeteer, so you’ll also need Chrome/Chromium – ideally latest.

Then you’ll have to launch the https server locally with:

npm run static

The first time you run visual regression tests, you’ll need to create reference screenshots with:

npm run visual-test:init

Then

npm run visual-test

This will test different scenarios, with possible interactions from the user e.g. displaying the TOC, changing the font or font-size, picking sepia or night mode…

A browser window/tab will open with the report so that you can take a deeper look.

If you encounter visual inconsistencies backstopJS doesn’t report on your first run, then do: