> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # URL Shortener > Guide to running a local URL shortener lab that creates a short link, generates traffic, and verifies each redirect is recorded in Postgres. This lab walks you through running the provided URL-shortener service locally, creating a real short link, and generating traffic against it to observe how each redirect is recorded in Postgres. Follow the steps below — hints and full solutions are available in the lab if you need them. ## What you'll do * Start the application and its dependencies with Docker Compose. * Mint a short link via the `/shorten` endpoint. * Use the provided hammer script to send 200 requests to that short link. * Inspect the application logs (and Postgres) to confirm every request was recorded. ## Prerequisites * Docker and Docker Compose installed * curl (or any HTTP client) * Access to the lab environment where the repository and `hammer.sh` script exist ## Quick lab steps 1. Start services: ```bash theme={null} docker compose up app redis pg ``` 2. Mint a short link: ```bash theme={null} POST /shorten - returns a short code in JSON ``` 3. Hammer the short link: ```bash theme={null} ./hammer.sh ``` 4. Inspect logs to confirm every request hit Postgres. ## Detailed example session Start the services: ```bash theme={null} docker compose up app redis pg ``` Mint a short link (example using curl): ```bash theme={null} curl -X POST localhost:8000/shorten -d 'https://kodekloud.com' ``` Example response: ```json theme={null} {"code": "2Bi"} ``` The service responds with a JSON payload containing the short code (for example, `2Bi`). Use that returned code when running the hammer script. For example, if the service returned `2Bi`, run: ```bash theme={null} ./hammer.sh 2Bi ``` That script will send 200 requests against the short link. Then inspect the application logs (or Postgres) to verify each request was recorded. If your environment uses a different short code (for example some exercises may reference `cat42`), substitute that code when invoking `./hammer.sh`. The important part is to target the actual short code returned by the `/shorten` endpoint. ## Inspecting logs and Postgres * Watch the application logs printed to the terminal from `docker compose up` — you should see log lines for each redirect request. * Alternatively, connect to the Postgres container and query the table that stores hits (table name may vary by lab). Example: ```bash theme={null} # enter the postgres container (example container name: pg) docker exec -it psql -U postgres # inside psql, run a simple count (replace table_name with actual table) SELECT COUNT(*) FROM table_name WHERE short_code = '2Bi'; ``` ## Endpoints reference | Endpoint | Method | Description | | - | - | - | | `/shorten` | `POST` | Mint a new short code for the provided long URL (request body is the long URL). | | `/

` | `GET` | Redirects to the original URL associated with `` and records the hit in the database. |

## Troubleshooting tips

* If you get an unexpected short code, always use the returned code when running `./hammer.sh`.
* Ensure the `app`, `redis`, and `pg` services are healthy in `docker compose ps` before sending traffic.
* If logs show errors connecting to Postgres, confirm network/service names in `docker-compose.yml` and that the DB has initialized.

## Links and references

* Docker Compose: [https://docs.docker.com/compose/](https://docs.docker.com/compose/)
* curl manual: [https://curl.se/docs/manpage.html](https://curl.se/docs/manpage.html)
* PostgreSQL documentation: [https://www.postgresql.org/docs/](https://www.postgresql.org/docs/)

Happy testing — this lab helps you observe real-world behavior where every redirect generates a database write, which is important when considering scalability and caching strategies.


  

  



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