# Building and Deploying a URL Shortener function with AWS Lambda

Building and Deploying a URL Shortener function with AWS Lambda
======================================================

URL shortening is a common practice in web development to create concise and user-friendly links. In this article, we'll explore how to build a serverless URL shortener using AWS Lambda. This setup will allow you to shorten long URLs into more manageable and shareable links.

Prerequisites
-------------

Before we start, make sure you have the following:

1.  An AWS account with access to AWS Lambda and API Gateway.
2.  AWS CLI installed and configured.

Steps to Create a URL Shortener
-------------------------------

### Step 1: Create a Lambda Function

1.  Open the AWS Lambda console.

2.  Click on "Create function."

3.  Choose "Author from scratch."

4.  Enter a name for your function (e.g., `URLShortenerFunction`).

5.  Select a runtime (e.g., Node.js).

6.  In the function code section, replace the existing code with the following Node.js code:

```
const { nanoid } = require('nanoid');

exports.handler = async (event) => {
    const originalUrl = event.queryStringParameters.url;
    const shortUrl = generateShortUrl();
    // Some form of persistent logic
    return {
        statusCode: 200,
        body: JSON.stringify({ originalUrl, shortUrl }),
    };
};

function generateShortUrl() {
    // Use nanoid to generate a short URL key
    return 'https://short.url/' + nanoid(7);
}
```
This code takes a long URL as a query parameter and returns a JSON object containing the original and short URLs.

Note: A design consideration for this solution should include a form of persistence where the original URL and the shortened URL are safely stored. 

7.  Under "Basic settings," set the timeout to a reasonable value (e.g., 10 seconds).

8.  Click "Deploy" to create the Lambda function.

### Step 2: Create an API Gateway

1.  Open the API Gateway console.
2.  Click on "Create API."
3.  Choose "HTTP API" and click "Build" to create a new API.
4.  In the "Configure routes" section, click "Add integration."
5.  Choose "Lambda function" and select the Lambda function you created.
6.  Click "Create" to create the API.

### Step 3: Deploy the API

1.  In the API Gateway console, select your API.
2.  Click on "Deployments" in the left sidebar.
3.  Click "Create" to create a new deployment.
4.  Choose a stage name (e.g., "prod") and click "Deploy."

### Step 4: Test the URL Shortener

1.  In the API Gateway console, navigate to the "Invoke URL" section to find your API endpoint.

2.  Use a tool like `curl` or a web browser to make a GET request to the endpoint with the `url` query parameter:

```
curl "<Your API Endpoint>?url=https://www.example.com"
```
Replace <Your API Endpoint> with the actual endpoint URL.

3. You should receive a JSON response containing the original and short URLs.

Congratulations! You've successfully created a serverless URL shortener using AWS Lambda and API Gateway. This example is a basic implementation, and you can enhance it by adding persistence, customizing the short URL format, and implementing redirection.