• 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 uses of GM_xmlhttpRequest to get and post 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.AspNetCore.Razor
• Microsoft.EntityFrameworkCore.SqlServer
• Microsoft.EntityFrameworkCore.Tools
• Magick.NET-Q8-AnyCPU

Setup

1. Install .NET Core
2. Clone and build the BantFlags solution.

3. Create the database using database.sql.

   • Change the password.

4. configure BantFlags/appsettings.example.json with your connection string and webroot (where you'll serve the flags from without a trailing /) 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.

     • For example, you may place BantFlags.dll and appsettings.json in /etc/bantflags/ and point webroot at /var/www/html and bantflags will server static content from that directory, or leave webroot empty and bantflags will look for static content in /etc/bantflags/wwwroot

5. Create a folder called keys in the directory you will be hosting bantflags from.

   • E.G. /etc/bantflags/keys/
   • ASP.NET Core uses some cryptic bullshit anti forgery token when processing HTML forms, and it's unable to persistantly store the decryption keys in memory on GNU + Linux. This directory will store said keys when you or users upload flags to /upload. The path is hardcoded to AppDomain.CurrentDomain.BaseDirectory, I.E. wherever the program is.
6. Add flags to the backend either by querying the database directly and placing images with the same name in {webroot}/flags/ or by using /upload.

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

   • Example nginx config.

8. Run with dotnet BantFlags.dll or create a service to run it as a daemon.

   • Example systemd service.
9. ???
10. 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.

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. See Docs/{endpoint} for version compatibility.