Deploying to Deno Deploy - Mini Project: Build & Apply

Deploying a Simple Web Server to Deno Deploy

📖 Scenario: You want to share a simple web page with your friends using Deno Deploy, a platform that lets you run Deno code on the internet easily.This project will guide you step-by-step to create a basic web server and deploy it to Deno Deploy.

🎯 Goal: Build a simple Deno web server that responds with a friendly message and prepare it for deployment on Deno Deploy.

📋 What You'll Learn

Create a basic HTTP server using Deno's standard library

Set a port number configuration variable

Write the core logic to handle HTTP requests and respond with a message

Add the final export statement for Deno Deploy compatibility

💡 Why This Matters

🌍 Real World

Deploying small web services or APIs quickly without managing servers.

💼 Career

Understanding Deno Deploy is useful for modern backend development and serverless deployment roles.

1

Set up the HTTP server import

Write an import statement to bring in the serve function from https://deno.land/std@0.203.0/http/server.ts.

Deno

# Your code here

Hint

Use import { serve } from the Deno standard library URL for HTTP server.

2

Define the port number

Create a constant variable called PORT and set it to Number(Deno.env.get("PORT") ?? "8000").

Deno

import { serve } from "https://deno.land/std@0.203.0/http/server.ts";

# Your code here

Hint

Use const PORT = Number(Deno.env.get("PORT") ?? "8000"); to set the port number from the environment variable or default to 8000.

3

Create the request handler

Write an async function called handler that takes a Request object and returns a new Response with the text "Hello from Deno Deploy!".

Deno

import { serve } from "https://deno.land/std@0.203.0/http/server.ts";

const PORT = Number(Deno.env.get("PORT") ?? "8000");

# Your code here

Hint

Define async function handler(request: Request) and return new Response("Hello from Deno Deploy!", { status: 200 }).

4

Start the server with export

Call serve with the handler function and port set to PORT. Export this call as the default export.

Deno

import { serve } from "https://deno.land/std@0.203.0/http/server.ts";

const PORT = Number(Deno.env.get("PORT") ?? "8000");

async function handler(request: Request): Promise {
  return new Response("Hello from Deno Deploy!", { status: 200 });
}

# Your code here

Hint

Use export default serve(handler, { port: PORT }) to start the server for Deno Deploy.

Practice

1. What is the main purpose of deno deploy in Deno?

easy

A. To run Deno scripts locally without internet

B. To install Deno on your computer

C. To create a new Deno project template

D. To publish your Deno app online as a serverless function

Solution

1. Step 1: Understand the command purpose

   deno deploy is used to publish apps online, not for local installs or running scripts.

2. Step 2: Match the description to the command

   Publishing as serverless functions matches the description of deno deploy.

3. Final Answer:

   To publish your Deno app online as a serverless function -> Option D

4. Quick Check:

   deno deploy = publish app online [OK]

Hint: Remember: deploy means publish online [OK]

Common Mistakes:

• Confusing deploy with install
• Thinking deploy runs code locally
• Assuming deploy creates projects

2. Which of the following is the correct command to deploy a Deno project located in the current folder?

easy

A. deno deploy --install

B. deno deploy .

C. deno run deploy

D. deno start deploy

Solution

1. Step 1: Identify the correct deploy syntax

   The command deno deploy . tells Deno to deploy the current folder project.

2. Step 2: Check other options for correctness

   Options B, C, and D are invalid commands for deployment.

3. Final Answer:

   deno deploy . -> Option B

4. Quick Check:

   Deploy current folder = deno deploy . [OK]

Hint: Use dot (.) to deploy current folder [OK]

Common Mistakes:

• Using deno run instead of deno deploy
• Adding wrong flags like --install
• Using deno start which is not a Deno command

3. Given this command run in your terminal: deno deploy https://github.com/user/myapp, what will happen?

medium

A. Deno will deploy the app from the GitHub repo URL as a serverless app

B. Deno will clone the repo locally but not deploy

C. Deno will throw a syntax error because URLs are not allowed

D. Deno will run the app locally without deploying

Solution

1. Step 1: Understand deploying from a repo URL

   Deno Deploy supports deploying directly from GitHub repo URLs.

2. Step 2: Analyze the command behavior

   The command deploys the app serverlessly from the given URL, no local clone or syntax error occurs.

3. Final Answer:

   Deno will deploy the app from the GitHub repo URL as a serverless app -> Option A

4. Quick Check:

   Deploy from URL = deploy serverless app [OK]

Hint: Deploy accepts GitHub URLs directly [OK]

Common Mistakes:

• Thinking deploy clones repo locally
• Assuming URLs cause syntax errors
• Confusing deploy with local run

4. You run deno deploy myapp but get an error saying "No such file or directory". What is the most likely cause?

medium

A. You forgot to install Deno before deploying

B. The internet connection is down

C. The folder or file named 'myapp' does not exist in the current directory

D. You need to run deno run myapp first

Solution

1. Step 1: Interpret the error message

   "No such file or directory" means the path 'myapp' is missing locally.

2. Step 2: Match error to cause

   Since deploy expects a valid path or URL, missing folder causes this error.

3. Final Answer:

   The folder or file named 'myapp' does not exist in the current directory -> Option C

4. Quick Check:

   Missing folder = No such file error [OK]

Hint: Check folder exists before deploying [OK]

Common Mistakes:

• Assuming Deno is not installed
• Blaming internet connection for local file errors
• Confusing deploy with run command

5. You want to deploy a Deno app that uses environment variables securely on Deno Deploy. Which approach is best?

hard

A. Set environment variables in Deno Deploy dashboard and access them via Deno.env.get()

B. Hardcode environment variables in your source code before deploying

C. Pass environment variables as command line arguments to deno deploy

D. Store environment variables in a local .env file and deploy it with your app

Solution

1. Step 1: Understand environment variable best practices

   Hardcoding or deploying .env files risks exposing secrets publicly.

2. Step 2: Use Deno Deploy features

   Deno Deploy dashboard allows secure environment variable setup accessed by Deno.env.get().

3. Final Answer:

   Set environment variables in Deno Deploy dashboard and access them via Deno.env.get() -> Option A

4. Quick Check:

   Secure env vars = dashboard + Deno.env.get() [OK]

Hint: Use dashboard for env vars, not code files [OK]

Common Mistakes:

• Hardcoding secrets in code
• Uploading .env files publicly
• Trying to pass env vars via deploy command