EPUB to Webpub

This repository is a converter between EPUBS and Webpubs. It can either be deployed as an endpoint service, consumed as a package within another Node service, or used as a CLI.

Features

• Exploded EPUB support (packaged EPUBS not currently supported)
• Remote and Local EPUB support
• AxisNow Encrypted EPUB support
• CLI
• Vercel-ready API handlers in /api

CLI Example

❯ epub-to-webpub ./samples/moby-epub2-exploded/META-INF/container.xml ./outputs/test.json

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██║╚██╗██║  ╚██╔╝  ██╔═══╝ ██║     
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╚═╝  ╚═══╝   ╚═╝   ╚═╝     ╚══════╝
 
   EPUB to Webpub Converter 

✔ Detected type: Local Exploded Epub
✔ Reading EPUB from: ./samples/moby-epub2-exploded/META-INF/container.xml
✔ Converting to Webpub...
✔ Formatting manifest...
✔ Writing Manifest to filesystem at: ./outputs/test.json
✔ Success!

Deployed API Endpoint

The API endpoints reside in /api and are deployed via Vercel at https://epub-to-webpub.vercel.app. The endpoints are:

• /api/[containerXmlUrl] - You provide the url to the container.xml file of an exploded EPUB, and we will return the webpub manifest.
• /api/axisnow/[isbn]/[book_vault_uuid] - You provide the isbn and the book_vault_uuid, and we return the webpub manifest.

Possible Future Features

• Packaged EPUB support.
• Better support for EPUB metadata and other EPUB features.

Architecture

There are three main pieces to the architecture:

1. The Epub class - This class serves as the in-memory respresentation of an Epub. It takes in the container.xml file and sources all the other files it needs from there.
2. The Fetcher class - The Fetcher is resonsible for sourcing the contents of a file. It allows the Epub class to not care how a file is fetched specifically. As such it is an abstract class, and has currently has two concrete implementations: LocalFetcher and RemoteFetcher. You could support a packaged EPUB by writing a LocalPackagedFetcher.
3. The /convert folder - Here we take in an Epub and return a WebpubManifest object. This conversion is exposed on the .webpubManifest property of an Epub.

Commands

• npm run start - start building the package in watch mode.
• npm run build - make a production build of the package. This will export CJS and ESmodules module formats to /dist. The cli application will be exported to /dist/cli.
• npm run test - perform a test run using Jest.
• npm run test:watch - perform a test run and re-test on code change.

Repo Organization

/api                 # vercel lambda functions
/mocks               # msw mocks for testing network-dependent code
/samples             # example EPUBS in various formats
/site                # basic index.html file to serve at api root
/src
   /__tests__        
   /cli              # cli entrypoint
   /convert          # generates a Webpub Manifest from an Epub class
   /WebpubManifestTypes   # ...
   Epub.ts           # the main Epub class
   Fetcher.ts        # abstract Fetcher class to be extended by LocalFetcher etc
   index.ts          # entrypoint of the npm module
   LocalFetcher.ts   
   RemoteFetcher.ts

Vercel Handlers

The API endpoints are located in /api and deployed to Vercel.

Testing

Tests are written with Jest. There is one particular thing to note here: we use MSW (Magic Service Worker) for testing network-based tasks. It intercepts the Node network requests and allows us to serve custom responses. In this case we serve files from the local filesystem in /samples, but it also allows us to test other responses a real server might give.