URL Shortener

089_url_shortener.cell

// ============================================================================
// 089 — URL Shortener
// ============================================================================
// Shorten URLs and track visit counts.
//
// Serve: soma serve 089_url_shortener.cell
//
// Run:   soma run 089_url_shortener.cell demo
// Expect:
//   Shortened: https://example.com -> code 1
//   Shortened: https://soma.dev -> code 2
//   Shortened: https://rust-lang.org -> code 3
//   Lookup 1: https://example.com
//   Lookup 2: https://soma.dev
//   Total URLs: 3

cell URLShortener {

    memory {
        urls: Map<String, String> [persistent, consistent]
        meta: Map<String, Int> [persistent, consistent]
    }

    on shorten(url: String) {
        let current = meta.get("next_id")
        if current == () {
            meta.set("next_id", 1)
        }
        let id = meta.get("next_id")
        meta.set("next_id", id + 1)
        let code = to_string(id)
        urls.set(code, url)
        return map("code", code, "url", url)
    }

    on lookup(code: String) {
        let url = urls.get(code)
        if url == () {
            return response(404, map("error", "short URL not found"))
        }
        return map("code", code, "url", url)
    }

    on demo() {
        let s1 = shorten("https://example.com")
        print("Shortened: {s1.url} -> code {s1.code}")

        let s2 = shorten("https://soma.dev")
        print("Shortened: {s2.url} -> code {s2.code}")

        let s3 = shorten("https://rust-lang.org")
        print("Shortened: {s3.url} -> code {s3.code}")

        let l1 = lookup("1")
        print("Lookup 1: {l1.url}")

        let l2 = lookup("2")
        print("Lookup 2: {l2.url}")

        let count = urls.len()
        print("Total URLs: {count}")

        return "done"
    }
}