HTTP to HTTPS redirect in Nginx - Step-by-Step Execution

Process Flow - HTTP to HTTPS redirect

Client sends HTTP request

↓

Nginx listens on port 80

↓

Check if request is HTTP

Yes↓

Send 301 redirect to HTTPS URL

↓

Client receives redirect and sends HTTPS request

↓

Secure connection established

The server listens for HTTP requests and responds with a redirect to the HTTPS version, prompting the client to reconnect securely.

Execution Sample

Nginx

server {
    listen 80;
    server_name example.com;
    return 301 https://$host$request_uri;
}

This nginx config listens on HTTP port 80 and redirects all requests to the HTTPS version of the same URL.

Process Table

Step	Client Request	Nginx Action	Response Sent	Client Action
1	HTTP GET http://example.com/page	Check if request is HTTP	301 Redirect to https://example.com/page	Receives redirect
2	HTTPS GET https://example.com/page	Serve HTTPS content (not shown here)	200 OK with content	Displays secure page
3	N/A	N/A	N/A	Process ends
Exit	N/A	No more HTTP requests	N/A	Secure connection established

💡 After redirect, client uses HTTPS; HTTP request handling ends.

Status Tracker

Variable	Start	After Step 1	After Step 2	Final
$host	example.com	example.com	example.com	example.com
$request_uri	/page	/page	/page	/page

Key Moments - 3 Insights

Why does nginx send a 301 redirect instead of serving content on HTTP?

Because the config explicitly returns a 301 redirect for all HTTP requests (see execution_table step 1), forcing clients to use HTTPS.

What happens if the client ignores the redirect?

The client will not get the secure content and stays on HTTP, which is not secure. The redirect is a signal to switch to HTTPS (execution_table step 1).

Why do we use $host and $request_uri in the redirect?

They preserve the original domain and path so the client is redirected to the exact same page but with HTTPS (see variable_tracker).

Visual Quiz - 3 Questions

Look at the execution table, what response does nginx send to the HTTP request at step 1?

A 200 OK with content

B 404 Not Found

C 301 Redirect to HTTPS URL

D 500 Internal Server Error

💡 Hint

Check the 'Response Sent' column in execution_table row for step 1.

At which step does the client send the HTTPS request?

A Step 2

B Step 3

C Step 1

D Exit

💡 Hint

Look at the 'Client Request' column in execution_table for HTTPS requests.

If we remove the 'return 301' line from the config, what happens to HTTP requests?

A They get redirected to HTTPS anyway

B Nginx serves HTTP content without redirect

C Nginx returns 404 error

D Nginx crashes

💡 Hint

The redirect is explicitly caused by 'return 301' in the config shown in execution_sample.

Concept Snapshot

nginx HTTP to HTTPS redirect:
- Listen on port 80 for HTTP
- Use 'return 301 https://$host$request_uri;' to redirect
- Sends permanent redirect to HTTPS URL
- Client then requests HTTPS URL
- Ensures secure connection by forcing HTTPS

Full Transcript

This visual execution shows how nginx redirects HTTP requests to HTTPS. When a client sends an HTTP request to port 80, nginx checks the request and responds with a 301 redirect to the same URL but with HTTPS. The client then follows this redirect and sends a new request over HTTPS. This process ensures all traffic uses a secure connection. Variables $host and $request_uri keep the domain and path unchanged during redirect. Without the redirect, nginx would serve HTTP content directly, which is less secure.