• BantFlags
  • Userscript
  • Backend
    • Prerequisites
    • .NET dependancies
    • Setup
    • Database
    • API
  • Backwards Compatibility

BantFlags

A user script and backend enabling user created flags on bant, originally based on extraflags.

Install bantflags

Userscript

The userscript takes advantage of GM_xmlhttpRequest to get and set flags with the backend. A user's flags are stored between pages using GM_setValue and GM_getValue.

Old versions of GreaseMonkey will be able to recieve updates to the script through use of the @updateURL and @downloadURL directives, though these were depricated sometime in GreaseMonkey 3.x and updates are only checked from the location the script was downloaded from so be careful where you upload links.

On self hosting, changing back_end to your domain should be all you need to do, but don't take this as fact.

The userscript has been designed specifically to target ECMAScript 2015 (ES6), making liberal use of arrow functions, and const/let declarations. Update your hecking browser.

Backend

Prerequisites

• .NET core 3.1
• Mariadb / mysql

.NET dependancies

• Nito.AsyncEX
• Newtonsoft.Json
• MySql.Data
• Microsoft.AspNetCore.Mvc.NewtonsoftJson
• Microsoft.AspNetCore.StaticFiles
• Microsoft.EntityFrameworkCore.SqlServer
• Microsoft.EntityFrameworkCore.Tools

Setup

1. Install .NET
2. Clone and build the BantFlags .NET project.

3. Create the database using database.sql.

   • Change the password.

4. configure BantFlags/appsettings.example.json with your connection string and webroot (the directory you wish to serve the flags from) and rename it to appsettings.json

   • The location of the BantFlags application and the served content are not necessarly the same. If you leave it empty, or provide a nonexistant path the application will look for the wwwroot folder inside the working directory.
   • This should be placed either in inside the working directory or the same directory as the program.
5. Add flags to the backend (currently only possible by querying the database directly), and place image with the same name in {webroot}/flags/.

6. Configure your webserver of choice to forward requests to kestral

   • Example nginx config.
7. Run the application
8. ???
9. profit.

Database

Tables look like this: posts

id	post_nr	board
1	12345	bant
2	56789	bant

flags

id	flag
1	patchouli
2	chen

postflags

id	post_nr	flag
1	1	1
2	1	2
2	2	2

where post_nr and flag in postflags are the id fields in their respective tables.

extraflags stores all of a post's flags in one table as a varchar, seperated by "||", which is split and joined by the script when getting and posting respectively. This is extraordinarily inefficient, but for their purposes it's not such a glaring issue (the highest amount of flags I've seen is 6). One aim of this rewrite is to greatly increase the amount of flags usable at once, and this database structure allows the maximum to be arbitrarily high.

API

The backend exposes three endpoints used by the userscript to get and post flags, and a flags directory storing the images themselves.

route	purpse
/api/get	Get flags using post numbers in the thread
/api/post	Add flags to the database
/api/flags	List the flags we support
/flags/*	The flag images

Backwards Compatibility

The API is 1:1 compatable with all previous versions of bantflags, but also encodes a new version variable when getting flags which allows for breaking changes in the script while the backend only sends data it knows is parsable.