# Based on articles:
# https://ruhighload.com/%D0%9A%D1%8D%D1%88%D0%B8%D1%80%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5+%D1%81+nginx
# https://wiki.enchtex.info/practice/nginx/cache
# https://gist.github.com/yanmhlv/5612256
# https://nginx.org/en/docs/http/ngx_http_fastcgi_module.html
# https://blog.runcloud.io/2017/10/28/nginx-caching-tutorial-wordpress.html
# https://www.digitalocean.com/community/tutorials/how-to-setup-fastcgi-caching-with-nginx-on-your-vps
# https://easyengine.io/wordpress-nginx/tutorials/single-site/fastcgi-cache-with-purging/


# move cache settings into /etc/nginx/nginx.conf if you want to use cache across many sites
# or set unique keys_zone name for each site
# /var/run/nginx-cache - path to cache on disk
# keys_zone=FASTCGICACHE:100m - unique name and memory pool size for keys dictionary
# inactive=6h delete page from cache if there was no requests for it in this period
# max_size=1g - limit of cache size on disk

fastcgi_cache_path /var/run/nginx-fastcgi-cache levels=1:2 keys_zone=FASTCGICACHE:100m inactive=6h max_size=1g;
fastcgi_cache_key "$scheme$request_method$host$request_uri";
fastcgi_cache_use_stale error timeout invalid_header http_500;
fastcgi_ignore_headers Cache-Control Expires Set-Cookie;

proxy_cache_path /var/run/nginx-proxy-cache levels=1:2 keys_zone=PROXYCACHE:100m inactive=6h max_size=1g;
proxy_cache_key "$scheme$request_method$host$request_uri";
proxy_cache_use_stale error timeout invalid_header http_500;
proxy_ignore_headers Cache-Control Expires Set-Cookie;


# Unfortunately you can't set *cache_valid time as a variable
# So you should change time values across the config into necessary
# Note: for forums use small cache time like 1-10 seconds
# https://deliciousbrains.com/microcaching-wordpress-nginx-improve-server-requests-2400/

server {
    listen   80;
    server_name example.com;

    access_log   /var/log/nginx/example.com.access.log;
    error_log    /var/log/nginx/example.com.error.log;

    root /usr/share/nginx/html;
    index index.php index.html index.htm;

    # Protect .git and other hidden files
    # Left logging for fail2ban
    location ~ /\. { deny all; }

    # Static content
    location ~* ^.+\.(ogg|ogv|svg|svgz|eot|otf|woff|mp4|ttf|rss|atom|jpg|jpeg|gif|png|ico|zip|tgz|gz|rar|bz2|doc|xls|exe|ppt|tar|mid|midi|wav|bmp|rtf)$ {
        gzip on;
        gzip_static on;
        gzip_disable "MSIE [1-6]\.(?!.*SV1)";
        gzip_proxied any;
        gzip_comp_level 6;
        gzip_buffers 16 8k;
        gzip_http_version 1.0;
        gzip_types
            text/plain
            text/css
            text/js
            text/xml
            text/x-component
            text/javascript
            application/javascript
            application/x-javascript
            application/json
            application/xml
            application/rss+xml
            image/svg+xml;
        expires max;

        try_files $uri =404;
    }

    #
    # Magic start here
    #

    # Enable SSI
    # https://en.wikipedia.org/wiki/Server_Side_Includes
    ssi on;

    # Enable caching for all by default
    set $skip_cache 0;

    # Disable cache for all requests except GET and HEAD
    if ($request_method !~ ^(GET|HEAD)$) {
        set $no_cache "1";
    }

    # Disable cache for all requests with a query string
    # You should disable this section if you use query string only for users tracking
    if ($query_string != "") {
        set $no_cache 1;
    }

    # Disable cache for all logged in users or recent commenters
    # Add your custom cookies here!
    if ($http_cookie ~* "nginx_no_cache|PHPSESSID") {
        set $skip_cache 1;
    }
    # Wordpress
    if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_no_cache|wordpress_logged_in") {
        set $skip_cache 1;
    }
    # Magento
    if ($http_cookie ~* "frontend_cid|frontend|sid|adminhtml|EXTERNAL_NO_CACHE") {
        set $skip_cache 1;
    }

    # Disable cache for uris containing the following segments
    # If is evil and you can speedup this section by using locations instead
    # https://www.nginx.com/resources/wiki/start/topics/depth/ifisevil/
    # https://serverfault.com/questions/509327/can-we-jump-to-another-location-from-a-location-in-nginx
    # Best practice
    if ($request_uri ~* "/ping|/metrics|/nginx_status|/admin|/login|/feed|index.php|sitemap(_index)?.xml") {
        set $skip_cache 1;
    }
    # Wordpress
    if ($request_uri ~* "/wp-admin/|/xmlrpc.php|wp-.*.php|/feed/|index.php|sitemap(_index)?.xml") {
        set $skip_cache 1;
    }
    # Magento
    # I copied this from varnish example
    # Better use varnish with magento autogenerated config instead
    # http://devdocs.magento.com/guides/v2.0/config-guide/varnish/config-varnish.html
    if ($request_uri ~* "(index|litespeed).php|admin|api|cron.php|/checkout/|/account/|/brand-ambassador/|/brand-ambassador-coupon/|/brand-ambassador-program/|/affiliateplusstatistic/|/brand-ambassador/index/listTransaction/|/brand-ambassador/index/paymentForm/|/brand-ambassador-program/index/index/|/brand-ambassador/banner/list/|/brand-ambassador-coupon/index/index/|/brand-ambassador/refer/index/|/brand-ambassador/index/payments/|/brand-ambassador/index/referrers/|/affiliateplusstatistic/statistic/index/|/brand-ambassador/account/edit/|/checkout/cart/|/repeat-delivery") {
        set $skip_cache 1;
    }

    # Example of proxy location
    location /backend {
        # Disable cache for all requests except GET and HEAD
        # And add our cookie for preventing caching for this user for next 5s
        # So user would see the changes
        if ($request_method !~ ^(GET|HEAD)$) {
            set $no_cache "1";

            add_header Set-Cookie "nginx_no_cache=1; Max-Age=5; Path=/";
            add_header X-Microcachable "0";
        }

        proxy_pass http://127.0.0.1:8080/;

        proxy_cache_bypass $skip_cache;
        proxy_no_cache $skip_cache;
        proxy_cache PROXYCACHE;
        proxy_cache_valid 499 502 503 1m;
        proxy_cache_valid 404 15m;
        proxy_cache_valid any 15m;
    }

    location / {
        try_files $uri $uri/ /index.php?$args;
    }

    location ~ \.php$ {
        # Disable cache for all requests except GET and HEAD
        # And add our cookie for preventing caching for this user for next 5s
        # So user would see the changes
        if ($request_method !~ ^(GET|HEAD)$) {
            set $no_cache "1";

            add_header Set-Cookie "nginx_no_cache=1; Max-Age=5; Path=/";
            add_header X-Microcachable "0";
        }

        try_files $uri =404;
        include fastcgi_params;
        fastcgi_pass 127.0.0.1:9000;

        fastcgi_cache_bypass $skip_cache;
        fastcgi_no_cache $skip_cache;
        fastcgi_cache FASTCGICACHE;
        fastcgi_cache_valid 499 502 503 1m;
        fastcgi_cache_valid 404 15m;
        fastcgi_cache_valid any 15m;
    }

    # This would work only with external fastcgi_cache_purge module
    # Or nginx+ commercial license
    # Otherwise you can just delete cache location and nginx would create it from zero
    #location ~ /purge(/.*) {
    #    fastcgi_cache_purge FASTCGICACHE "$scheme$request_method$host$1";
    #    fastcgi_cache_purge PROXYCACHE "$scheme$request_method$host$1";
    #}

}