res.redirect for redirections in Express - Step-by-Step Execution

Concept Flow - res.redirect for redirections

Client sends request

↓

Server receives request

↓

Server calls res.redirect(url)

↓

Server sends 302 status + Location header

↓

Client receives redirect response

↓

Client automatically requests new URL

↓

New resource served to client

This flow shows how a server tells the browser to go to a new URL using res.redirect, causing the browser to request that new URL.

Execution Sample

Express

app.get('/old-page', (req, res) => {
  res.redirect('/new-page');
});

When a client requests '/old-page', the server responds by redirecting them to '/new-page'.

Execution Table

Step	Action	Server Response	Client Behavior
1	Client requests '/old-page'	No response yet	Sends HTTP GET to server
2	Server receives request	No response yet	Waiting for server response
3	Server calls res.redirect('/new-page')	Sends HTTP 302 status with Location: /new-page header	Receives redirect response
4	Client receives 302 redirect	Response sent	Automatically requests '/new-page' URL
5	Server receives new request for '/new-page'	Processes and sends resource	Receives new page content
6	Client renders '/new-page' content	Response complete	Displays new page to user

💡 Redirect completed when client requests and receives the new URL content.

Variable Tracker

Variable	Start	After Step 3	After Step 5	Final
requestedURL	undefined	/old-page	/new-page	/new-page
responseStatus	undefined	302	200	200
responseHeaders.Location	undefined	/new-page	undefined	undefined

Key Moments - 2 Insights

Why does the client make a second request after res.redirect is called?

Because res.redirect sends a 302 status with a Location header telling the client to go to a new URL, so the client automatically requests that new URL (see execution_table step 4).

Does res.redirect send the content of the new page immediately?

No, it only sends a redirect response (302 status and Location header). The client must request the new page separately (see execution_table steps 3 and 5).

Visual Quiz - 3 Questions

Look at the execution table, what HTTP status code does the server send when res.redirect is called?

A 404

B 302

C 200

D 500

💡 Hint

Check the 'Server Response' column at step 3 in the execution_table.

At which step does the client send the request for the new URL after redirection?

A Step 4

B Step 5

C Step 2

D Step 6

💡 Hint

Look at the 'Client Behavior' column to see when the new URL request happens.

If the server changed res.redirect('/new-page') to res.redirect(301, '/new-page'), what would change in the execution table?

A The client would not request the new URL

B The server would send the new page content immediately

C The status code at step 3 would be 301 instead of 302

D No change at all

💡 Hint

Focus on the 'Server Response' status code at step 3.

Concept Snapshot

res.redirect(url) sends a 302 redirect response to the client.
The client then requests the new URL automatically.
The server does NOT send the new page content immediately.
Use res.redirect(status, url) to specify other redirect codes like 301.
Commonly used to move users from old URLs to new ones.

Full Transcript

When a client asks the server for a page, the server can tell the client to go somewhere else by using res.redirect. This sends a special response with status 302 and a Location header. The client sees this and automatically asks for the new page. The server then sends the new page content. This process helps move users smoothly from one URL to another without confusion.