Unless you wish to contribute to the project, I recommend using the hosted version at [devdocs.io](https://devdocs.io). It's up-to-date and works offline out-of-the-box.
DevDocs requires Ruby 2.5.1, libcurl, and a JavaScript runtime supported by [ExecJS](https://github.com/rails/execjs#readme) (included in OS X and Windows; [Node.js](https://nodejs.org/en/) on Linux). Once you have these installed, run the following commands:
Finally, point your browser at [localhost:9292](http://localhost:9292) (the first request will take a few seconds to compile the assets). You're all set.
The `thor docs:download` command is used to download pre-generated documentations from DevDocs's servers (e.g. `thor docs:download html css`). You can see the list of available documentations and versions by running `thor docs:list`. To update all downloaded documentations, run `thor docs:download --installed`.
**Note:** there is currently no update mechanism other than `git pull origin master` to update the code and `thor docs:download --installed` to download the latest version of the docs. To stay informed about new releases, be sure to [watch](https://github.com/freeCodeCamp/devdocs/subscription) this repository.
The app's main goals are to: keep load times as short as possible; improve the quality, speed, and order of search results; maximize the use of caching and other performance optimizations; maintain a clean and readable user interface; be fully functional offline; support full keyboard navigation; reduce “context switch” by using a consistent typography and design across all documentations; reduce clutter by focusing on a specific category of content (API/reference) and indexing only the minimum useful to most developers.
**Note:** DevDocs is neither a programming guide nor a search engine. All our content is pulled from third-party sources and the project doesn't intend to compete with full-text search engines. Its backbone is metadata; each piece of content is identified by a unique, "obvious" and short string. Tutorials, guides and other content that don't meet this requirement are outside the scope of the project.
The web app is all client-side JavaScript, written in [CoffeeScript](http://coffeescript.org), and powered by a small [Sinatra](http://www.sinatrarb.com)/[Sprockets](https://github.com/rails/sprockets) application. It relies on files generated by the [scraper](#scraper).
Many of the code's design decisions were driven by the fact that the app uses XHR to load content directly into the main frame. This includes stripping the original documents of most of their HTML markup (e.g. scripts and stylesheets) to avoid polluting the main frame, and prefixing all CSS class names with an underscore to prevent conflicts.
Another driving factor is performance and the fact that everything happens in the browser. `applicationCache` (which comes with its own set of constraints) and `localStorage` are used to speed up the boot time, while memory consumption is kept in check by allowing the user to pick his/her own set of documentations. The search algorithm is kept simple because it needs to be fast even searching through 100,000 strings.
This allows the code to take advantage of the latest DOM and HTML5 APIs and make developing DevDocs a lot more fun!
## Scraper
The scraper is responsible for generating the documentation and index files (metadata) used by the [app](#app). It's written in Ruby under the `Docs` module.
There are currently two kinds of scrapers: `UrlScraper` which downloads files via HTTP and `FileScraper` which reads them from the local filesystem. They both make copies of HTML documents, recursively following links that match a set of rules and applying all sorts of modifications along the way, in addition to building an index of the files and their metadata. Documents are parsed using [Nokogiri](http://nokogiri.org).
These modifications are applied via a set of filters using the [HTML::Pipeline](https://github.com/jch/html-pipeline) library. Each scraper includes filters specific to itself, one of which is tasked with figuring out the pages' metadata.
The end result is a set of normalized HTML partials and two JSON files (index + offline data). Because the index files are loaded separately by the [app](#app) following the user's preferences, the scraper also creates a JSON manifest file containing information about the documentations currently available on the system (such as their name, version, update date, etc.).
This software is licensed under the terms of the Mozilla Public License v2.0. See the [COPYRIGHT](https://github.com/freeCodeCamp/devdocs/blob/master/COPYRIGHT) and [LICENSE](https://github.com/freeCodeCamp/devdocs/blob/master/LICENSE) files.
Please do not use the name DevDocs to endorse or promote products derived from this software without my permission, except as may be necessary to comply with the notice/attribution requirements.
I also wish that any documentation file generated using this software be attributed to DevDocs. Let's be fair to all contributors by giving credit where credit's due. Thanks!
