Cesar Chew at 17:24, 24 November 2014

2014-11-24T17:24:47Z

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{{Cat|Nginx|03}}
{{Cat|Apache|05}}

<slideshow style="nobleprog" headingmark="⌘" incmark="…" scaled="true" font="Trebuchet MS" >
;title: Rewrites and Redirects
;author: Sam Bashton (NobleProg Ltd)
</slideshow>

=== 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/

Rewrites and Redirects - Revision history

Cesar Chew at 17:24, 24 November 2014