Adventure Library

WDI mini-project for 2/13/2014

This is your start for making your node in our distributed text adventure library.

Each of you will build a website which allows a user to view text adventures, click through the pages, and add text adventures to the database. Here's the twist. A user on your site will also be able to put in the name of another text adventure library, and your site will retrieve all the text adventures which were made in that library, and all of the other libraries that that library knows about. Conversely, your library will make available via JSON endpoints all the text adventures which are locally made, and a list of all the servers which your server knows about.

Subjects covered in this project:

• Testing
• Relationships (has_many and belongs_to)
• Using JSON APIs
• Responding with JSON
• Background workers
• Controllers and Views

The HTML user interface

A user is able to go to a form to build a NEW text adventure. Submitting this form will CREATE an adventure. When an adventure is created, it will be automatically assigned a guid, a Global Unique identifier, using SecureRandom. (SecureRandom.urlsafe_base64(10))

A user can EDIT and UPDATE an adventure which was created on the local server by changing the title, deleting pages, or adding pages.

A user can view an INDEX of adventures and click through to a specific adventure.

A user can be SHOWn an adventure. This will start them on the page for that adventure which has the name "start". I.E, adventure.pages.where(:name => "start"). The text for that page will be shown, with any connections between pages in that text turned into links in the HTML. Connections between pages are in the following format: [[link text|linked_to_page_name]]. See the section "Displaying the text of a Page" for information on how to turn these double bracket links into anchor tags.

A user can click through links on a page to go to connected pages.

A user can go to a form to enter in the URL of another library server. When a user submits that form, it will start the library scraping process.

The JSON interface

A JSON client can GET '/libraries' to get a list of libraries which the current server knows about in JSON format.

A JSON client can GET '/adventures' to get a list of adventures created on the local library server, with their pages.

The Library scraping process

When a user submits a new library URL, "alibrary.com", this should start the library scraping process. Your library will save that server ("alibrary.com") to the database, then set off jobs to GET all the adventures from that library ("alibrary.com/adventures.json") and GET all the libraries ("alibrary.com/libraries.json") which that library knows about.

For each library the scraper got from libraries.json, check if you have scraped that library before. If you have, leave it be. If you have not seen it before, scrape that library as well.

If your library tries to scrape itself, it will retrieve a list of adventures and libraries which all exist on the local database. The libraries will be safely ignored, since you have seen them all before. To make sure the adventures are not modified, do not update an adventure unless the updated_at field of the retrieved JSON is greater than the updated_at field of the local adventure with the same GUID. In this way self-scraping will happen, but will cause no changes. This is simpler than preventing self-scraping from happening.

In the scraping process, if other servers are returning "id" fields from their local database, do not use their ids to save data to your database. Save just the fields you want. They might conflict with the ids of data in your database. In your JSON api, it would be considerate to not include the "id" field in your responses.

BONUS: After a library has been added to the server, use Sidetiq to retrieve updated adventures from that server on a regular basis. Overwrite the correct adventure in your database using the GUID.

Displaying the text of a Page

We can use Ruby's String#gsub functionality to substitute one substring for another throughout the string. We use a regular expression to detect the pattern of the link in double brackets, then in the passed block, return the HTML link (anchor tag) which we want to replace it with.

We've provided a method linkify_page in PagesHelper which takes a page and returns the text with the double bracket links replaced with anchor tags. It assumes you have not changed the routes, so a page should be accessible at:

/adventures/:adventure_id/pages/:page_id

The schema

Adventure:

• has many Pages
• belongs to a Library. If library_id is nil, the adventure is local.
• has a title (string)
• has an author (string)
• has timestamps
• has a GUID (string)

Page:

• belongs to an Adventure
• has a name (string)
• has text (text)

Library:

• has many Adventures
• has a URL

Possible order of work:

• Write the migrations and models. I suggest you at least test the guid setting for adventures.
• Let a user see a list of adventures and get the JSON spec for a list of adventures passing
• Let a user click through an adventure (starting with the page whose name is "start"). You'll use the helper method linkify_page for this. Give it a Page object, and it will give you the text of the page, with double bracket style links ([[Go to the end|endpage]])turned into tags.
• Get the scraper working from rails console. Make a method you can call from rails console which will set off the scraping. I.E. library.scrape will go to that library's url and scrape the adventures and known libraries.
• Make a sidekiq worker which calls your scraping function.
• Let a user submit a url to scrape, which will set the worker going.
• Build a story creation and editing interface.