Add Nginx redirect post

source/_posts/2017-01-31-nginx-redirects-with-query-string-arguments.md

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+---
+title: Nginx Redirects With Query String Arguments
+tags: [nginx]
+use: [posts]
+---
+This is an example of how my Nginx configuration looked to redirect from an old domain to a new one, and also to redirect from the root `example.com` domain to the canonical `www` subdomain.
+```
+server {
+  listen 80;
+
+  server_name example.com;
+  server_name my-old-domain.com;
+  server_name www.my-old-domain.com;
+
+  return 301 https://www.example.com$uri;
+}
+```
+
+It also redirects the URI value, e.g. from `http://example.com/test` to `http://example.com/test`, but I noticed recently though that any the query string would be lost - e.g. `http://example.com/?test` would redirect to `http://www.example.com` and the `?test` would be dropped. The application that I built references images based on the query string, so I wanted these to be included within the redirect.
+
+This was fixed by making a small change to my `return` statement.
+
+Before:
+
+    return 301 https://www.example.com$uri;
+
+After:
+
+    return 301 https://www.example.com$uri$is_args$args;
+
+`$is_args` is an empty string if there are no arguments, or a `?` to signify the start of the query string. `$args` then adds the arguments (`$query_string` could also be used with the same result).
+
+Here is an demo of it working on this website:
+
+![](/assets/images/blog/nginx-redirect-with-args.gif)
+
+## Resources
+
+- [Query string](https://en.wikipedia.org/wiki/Query_string)
+- [Nginx ngx_http_core_module](http://nginx.org/en/docs/http/ngx_http_core_module.html)