League Stats

A full-stack web application for looking up League of Legends player statistics, match history, and champion information.

Features

• Player search by Riot ID (name + tag)
• Recent match history with KDA, items, and game duration
• Per-champion statistics (win rate, average KDA, most built items)
• Champion mastery integration
• Ranked stats display
• Champion info pages (abilities, lore, skins)
• Responsive dark-themed UI

Tech Stack

Backend

• C# / .NET 8
• AWS Lambda (serverless compute)
• AWS API Gateway (REST API)
• AWS DynamoDB (caching)
• AWS SSM Parameter Store (secrets management)
• AWS CDK in C# (infrastructure as code)

Frontend

• HTML / CSS / JavaScript
• Riot Data Dragon (champion images, item icons)

External APIs

• Riot Games API (match history, player data, champion mastery)

Architecture

Frontend (S3 + CloudFront)
    │
    ▼
API Gateway
    │
    ├── GET /champions → Lambda (GetChampions)
    ├── GET /champion/{name} → Lambda (GetChampionPage)
    └── GET /player/{name}/{tag} → Lambda (GetPlayerProfile)
                │
                ├── Riot Games API (match data, mastery)
                ├── Data Dragon (static champion/item data)
                └── DynamoDB (response caching)

Deployment

Prerequisites

• AWS CLI configured (aws configure)
• .NET 8 SDK
• AWS CDK CLI (npm install -g aws-cdk)
• Riot Games API key (developer.riotgames.com)

Setup

1. Store your Riot API key in SSM:

aws ssm put-parameter --name "/league-builds/riot-api-key" --value "RGAPI-your-key" --type SecureString --region eu-west-2

2. Publish the Lambda code:

cd src/LeagueBuilds.Api
dotnet publish -c Release -o bin/Release/net8.0/publish

3. Deploy:

cd src/LeagueBuilds.Cdk
cdk deploy

Environment Variables (set by CDK)

Variable	Purpose
RIOT_API_KEY_PARAM	SSM parameter name for Riot API key
CACHE_TABLE_NAME	DynamoDB table name

API Endpoints

Endpoint	Description
GET /champions	List all champions with icons
GET /champion/{name}	Champion info (abilities, lore, skins)
GET /champion/{name}?player={name}&tag={tag}	Champion info with personal stats
GET /player/{name}/{tag}	Player profile, match history, mastery

Project Structure

league-builds/
├── src/
│   ├── LeagueBuilds.Api/
│   │   ├── Functions/
│   │   │   ├── GetChampions.cs
│   │   │   ├── GetChampionPage.cs
│   │   │   └── GetPlayerProfile.cs
│   │   ├── Services/
│   │   │   ├── RiotApiService.cs
│   │   │   ├── PlayerStatsService.cs
│   │   │   ├── CacheService.cs
│   │   │   └── ConfigService.cs
│   │   └── Models/
│   │       ├── PlayerProfile.cs
│   │       ├── ChampionPageData.cs
│   │       ├── ChampionDetailStats.cs
│   │       └── ApiResponse.cs
│   └── LeagueBuilds.Cdk/
│       ├── Program.cs
│       └── LeagueBuildsStack.cs
├── frontend/
│   ├── index.html
│   ├── styles.css
│   └── app.js
└── test/
    └── LeagueBuilds.Tests/

Riot API Note

Development API keys expire every 24 hours. For persistent access, apply for a production key at developer.riotgames.com.

To update an expired key:

aws ssm put-parameter --name "/league-builds/riot-api-key" --value "RGAPI-new-key" --type SecureString --region eu-west-2 --overwrite

Cost

Service	Monthly Cost
Lambda	~$0 (pay per request)
API Gateway	~$0-1
DynamoDB (on-demand)	~$0
S3 + CloudFront	~$0.50
Total	Under $2/month

Known Limitations

• Riot development keys expire every 24 hours
• Match history limited to most recent 200 games (API constraint)
• Champion mastery data reflects all-time play, stats are from recent matches only
• Some champion skins (certain named chromas) may still appear in the skins list