Rewrites and Redirects

title

Rewrites and Redirects

author

Sam Bashton (NobleProg Ltd)

Redirects ⌘

• Content moved, but still want it to be available at another location?
• Use a redirect
• Very very common, in part thanks to SEO

Simple redirect ⌘

• page at `/calzado/` has been moved to `/zapatos/`
• We need to send a redirect telling all clients it has been permanently moved

302: Found ⌘

• Used when a document at one URL should in fact be requested via another
• Server sends back a redirect to the other location
• Browser makes two requests - one for the initial URL, one for the location given in the reply
• Browser should not cache this redirect

301: Moved Permanently ⌘

• Sends back a redirect to the browser with the new HTTP location
• Browser then makes a second request, to the location given in the reply to the first request
• Browser can cache this redirect
• Also obeyed by search engines (Google)

Our shoe redirect ⌘

```
location /calzado {
 rewrite ^ http://localhost:8080/zapatos;
}
```

Testing our redirect ⌘

We can easily test the redirect using `curl`

```
$ curl -I http://localhost/calzado/
HTTP/1.1 302 Moved Temporarily
Server: nginx/1.4.1
Date: Tue, 28 May 2013 13:59:32 GMT
Content-Type: text/html
Content-Length: 160
Connection: keep-alive
Location: http://localhost:8080/zapatos/
```

Changing the 302 to a 301 ⌘

```
location /calzado {
 rewrite ^ http://localhost:8080/zapatos permanent;
}
```

More complex redirects ⌘

• Now we need to redirect mens and womens shoes
• We can use both a regex location match and regex rewrite:

```
location ~ /(hombre|mujer)/calzado/ {
 rewrite /(hombre|mujer)/calzado/ http://localhost:8080/$1/zapatos/;
}
```

Test complex redirect ⌘

```
$ curl -I http://localhost/mujer/calzado/
HTTP/1.1 302 Moved Temporarily
Server: nginx/1.4.1
Date: Tue, 28 May 2013 14:20:24 GMT
Content-Type: text/html
Content-Length: 160
Connection: keep-alive
Location: http://localhost:8080/mujer/zapatos/
```

Adding more complexity ⌘

• We now want our redirect only for the host example.es
• We can add a conditional

```
location ~ /(hombre|mujer)/calzado/ {
 if ($host = "example.es") {
   rewrite /(hombre|mujer)/calzado/ http://localhost:8080/$1/zapatos/;
 }
}
```

Testing if ⌘

```
$ curl -I http://localhost/mujer/calzado/
HTTP/1.1 404 Not Found
Server: nginx/1.4.1
Date: Tue, 28 May 2013 14:38:59 GMT
Content-Type: text/html
Content-Length: 168
Connection: keep-alive
$ curl -I http://example.es/mujer/calzado/
HTTP/1.1 302 Moved Temporarily
Server: nginx/1.4.1
Date: Tue, 28 May 2013 14:39:04 GMT
Content-Type: text/html
Content-Length: 160
Connection: keep-alive
Location: http://localhost:8080/mujer/zapatos/
```
=== Rewrites ⌘===

• Much the same as redirects, but done server side
• No visibility to the end user

Rewrite example

• Requests for `/en/shoes/` should be fulfilled by the content in the

 `/zapatos/` directory
```
location / {
 root /usr/share/nginx/html;
 index index.html index.html;
 rewrite /en/shoes/ /zapatos/;
}
```

try_files ⌘

• One common pattern is for rewrites to be used only if a file

 of the corresponding name doesn't exist on disk

• For example, everything should be handled by index.php, with the path

 passed as a query string
```

location / {

  root /usr/share/nginx/html;
 index index.php;
 try_files $uri $uri/ /index.php?q=$uri;
}
```

Exercise ⌘

• Implement serving of /extra/ from /usr/share/doc/HTML using a rewrite
• Make requests to /foo/ send a permanent redirect to /extra/