URL Shortener — Complete Example

A production-style URL shortener demonstrating injectable's full feature set. Source: examples/11_url_shortener.rs.

Run:

cargo run --example 11_url_shortener --features axum

Dependency graph (4 levels)

AppConfig            (level 0 — constructor injection, reads env)
    ↓ make_db_pool   (#[injectable(factory)] — called once per service type)
AuthService          (level 1 ← pool)
UrlService           (level 1 ← pool, Arc<AppConfig>)
AnalyticsService     (level 2 ← pool, Arc<UrlService>)
RedirectService      (level 3 ← Arc<UrlService>, Arc<AnalyticsService>)
LinkPreviewService   (level 2 ← Arc<UrlService>, Arc<AppConfig>)

Key patterns demonstrated

Feature	Where used
#[injectable(factory)] factory	make_db_pool reads Inject<AppConfig>
use_factory_async	pool field on AuthService, UrlService, AnalyticsService
Arc<T> service deps	AnalyticsService holds Arc<UrlService>
#[injectable(post_construct)]	DB migrations on each service
#[injectable(pre_destruct)]	Pool shutdown on AuthService
Custom Axum extractor	AuthenticatedUser calls Inject::<AuthService>::extract
Multiple Inject<T> in one handler	dashboard handler injects AnalyticsService

Quick start

# Register and get API key
KEY=$(curl -s -X POST http://localhost:3000/api/register \
  -H 'Content-Type: application/json' \
  -d '{"email":"alice@example.com"}' | python3 -c "import sys,json;print(json.load(sys.stdin)['api_key'])")

# Shorten a URL
CODE=$(curl -s -X POST http://localhost:3000/api/shorten \
  -H "x-api-key: $KEY" -H 'Content-Type: application/json' \
  -d '{"url":"https://www.rust-lang.org","title":"Rust"}' | python3 -c "import sys,json;print(json.load(sys.stdin)['code'])")

# Follow redirect (records click)
curl -L http://localhost:3000/$CODE

# Dashboard
curl http://localhost:3000/api/dashboard -H "x-api-key: $KEY"

See the full source at examples/11_url_shortener.rs.