how to force Nginx to override header?

Question

I'm trying to display my sitemaps. Browsers display my sitemap index as xml but treat post sitemaps as plain text.

I tried to override content type with below configuration but it didn't help.

location ~ \.xml$ {
    proxy_hide_header Content-Type;
    add_header Content-Type "application/xml";
}

How do I force nginx to set content type as "application/xml" ?

Btw sitemaps in nutshell..

sitemap index

<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <sitemap>
        <loc>http://www.example.com/sitemaps/sitemap-1.xml</loc>

        <lastmod>2019-02-10T12:22:18+00:00</lastmod>
    </sitemap>
    ....
</sitemapindex>

and one of posts sitemaps

<loc>http://www.example.com/en</loc>
    <xhtml:link rel="alternate" hreflang="en" href="http://example.com/en" />
    <xhtml:link rel="alternate" hreflang="fr" href="http://example.com/fr" />
    <lastmod>2019-02-10T00:00:00+00:00</lastmod>
    <changefreq>daily</changefreq>
    <priority>1</priority>
</url>
<url>
.....

I use default laravel nginx configuration

Answer 1

You can't actually set the Content-Type header for proxy_passed content using plain nginx. You need to compile it with headers-more-nginx-module for that functionality. After you got that module, setting headers is as easy as:

location ~ \.xml$ {
    ... your config ...
    more_set_headers "Content-Type: application/xml";
    ... proxy_pass settings ...
}

Alternatively, if those sitemap files of yours are not actually generated by backend server on the fly and they actually exists in your website folder you don't really need to use proxy_pass. Try serving them directly by nginx instead with:

location ~ \.xml$ {
    try_files $uri =404;
}

If you don't know how to compile your nginx with external module on Ubuntu 18, just follow this simple steps:

1. Become superuser with this command so we can skip typing sudo every time:

   sudo su

2. Install prerequisites for building nginx by using the following command:

   apt install -y build-essential git tree libpcre3-dev libssl-dev zlib1g-dev libxslt1-dev libgd-dev libgeoip-dev

3. Download latest nginx source from http://nginx.org/en/download.html

   wget http://nginx.org/download/nginx-1.15.8.tar.gz

4. Unpack it & enter the source tree directory

   tar xzfv nginx-1.15.8.tar.gz && cd nginx-1.15.8

5. Get the headers-more-nginx-module:

   git clone https://github.com/openresty/headers-more-nginx-module

6. Get the configuration arguments of your installed nginx (by running nginx -V), add the --add-module=/path/to/headers-more-nginx-module option to them or just configure with the following command:

   ./configure --with-cc-opt='-g -O2 -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fPIC' --user=www-data --group=www-data --prefix=/etc/nginx --conf-path=/etc/nginx/nginx.conf --sbin-path=/usr/sbin/nginx --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_geoip_module=dynamic --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_sub_module --with-http_xslt_module=dynamic --with-stream=dynamic --with-stream_ssl_module --with-mail=dynamic --with-mail_ssl_module --add-module=./headers-more-nginx-module

7. make && make install

8. Now you have headers-more-nginx-module in your system & full support for those config directives, I mentioned earlier.