Rewrite flags (last, break, redirect, permanent) in Nginx - Step-by-Step Execution

Process Flow - Rewrite flags (last, break, redirect, permanent)

Request comes in

↓

Rewrite rule matches?

No→Serve original URI

Yes↓

Apply rewrite with flag

↓

last

↓

break

↓

redirect

↓

permanent

When a rewrite rule matches, nginx applies the flag to decide how to handle the request next: restart, stop, or redirect.

Execution Sample

Nginx

rewrite ^/oldpath/(.*)$ /newpath/$1 last;
rewrite ^/temp/(.*)$ /tempfile break;
rewrite ^/go/(.*)$ http://example.com/$1 redirect;
rewrite ^/perm/(.*)$ http://example.com/$1 permanent;

Four rewrite rules showing different flags: last restarts location search, break stops rewriting, redirect sends 302, permanent sends 301.

Process Table

Step	Request URI	Rewrite Rule Matched	Flag	Action Taken	Resulting URI or Response
1	/oldpath/page	^/oldpath/(.*)$	last	Restart location search with /newpath/page	/newpath/page
2	/newpath/page	No match	-	Serve /newpath/page	/newpath/page
3	/temp/file	^/temp/(.*)$	break	Stop rewriting, continue with /tempfile	/tempfile
4	/tempfile	No rewrite	-	Serve /tempfile	/tempfile
5	/go/home	^/go/(.*)$	redirect	Send 302 redirect to http://example.com/home	302 Redirect to http://example.com/home
6	/perm/about	^/perm/(.*)$	permanent	Send 301 redirect to http://example.com/about	301 Redirect to http://example.com/about
7	/other	No match	-	Serve /other	/other

💡 Execution stops when no rewrite rule matches or after redirect response is sent.

Status Tracker

Variable	Start	After Step 1	After Step 3	After Step 5	After Step 6	Final
Request URI	/oldpath/page	/newpath/page	/temp/file	/go/home	/perm/about	/other
Rewrite Rule Matched	None	^/oldpath/(.*)$	^/temp/(.*)$	^/go/(.*)$	^/perm/(.*)$	None
Action Taken	None	Restart location search	Stop rewriting	302 redirect	301 redirect	Serve original

Key Moments - 3 Insights

Why does the 'last' flag cause nginx to restart location search?

Because 'last' tells nginx to treat the rewritten URI as a new request and search for matching location blocks again, as shown in step 1 and 2 of the execution_table.

What happens when the 'break' flag is used in a rewrite?

'break' stops further rewrite processing and continues with the current location using the rewritten URI, as seen in step 3 and 4.

How do 'redirect' and 'permanent' flags differ in their HTTP response?

'redirect' sends a temporary 302 redirect, while 'permanent' sends a 301 permanent redirect, demonstrated in steps 5 and 6.

Visual Quiz - 3 Questions

Look at the execution_table, what is the Request URI after step 1?

A /oldpath/page

B /temp/file

C /newpath/page

D /go/home

💡 Hint

Check the 'Request URI' column in row for step 1.

At which step does nginx send a 301 redirect response?

A Step 6

B Step 5

C Step 3

D Step 2

💡 Hint

Look at the 'Action Taken' and 'Resulting URI or Response' columns for redirect types.

If the 'break' flag was replaced with 'last' in step 3, what would happen?

A Nginx would serve /temp/file without rewriting

B Nginx would restart location search with /tempfile

C Nginx would send a redirect to /tempfile

D Nginx would stop processing and serve original URI

💡 Hint

Compare the behavior of 'break' vs 'last' flags in the concept_flow and execution_table.

Concept Snapshot

nginx rewrite flags control request handling:
- last: rewrite and restart location search
- break: rewrite and stop rewriting, continue current location
- redirect: send 302 temporary redirect
- permanent: send 301 permanent redirect
Use flags to control URL rewriting and client response.

Full Transcript

When nginx receives a request, it checks rewrite rules. If a rule matches, it applies the rewrite and uses the flag to decide what to do next. The 'last' flag restarts location search with the new URI, allowing further processing. The 'break' flag stops rewriting and continues with the current location using the rewritten URI. The 'redirect' flag sends a temporary 302 redirect to the client, while 'permanent' sends a 301 permanent redirect. If no rewrite matches, nginx serves the original URI. This flow helps control how URLs are rewritten and how clients are redirected.