default.conf

proxy_cache_path /etc/nginx/cache levels=1:2 keys_zone=prerendercloud_cache:10m max_size=100m inactive=60m use_temp_path=off;

server {
    set $root /usr/share/nginx/html;

    # must use resolver and $variable to fix nginx inability to respect TTL of headless-render-api.com's load balancer
    # https://tenzer.dk/nginx-with-dynamic-upstreams/
    resolver 8.8.8.8;
    set $prerendercloud 'service.headless-render-api.com';

    listen 80;
    server_name localhost;

    location / {
        root $root;
        try_files $uri @prerendercloud;
    }

    location @prerendercloud {
        # gzip all traffic to service.headless-render-api.com
        proxy_set_header Accept-Encoding "gzip";
        # un-gzip traffic from service.headless-render-api.com if the client doesn't support it
        gunzip on;

        root $root;
        # get token after signing up at https://headless-render-api.com
        # proxy_set_header X-Prerender-Token YOUR_SECRET_API_TOKEN_HERE;

        # API options (HTTP headers)
        # read https://headless-render-api.com/docs/api before enabling any of these
        # proxy_set_header "Prerender-Disable-Ajax-Preload" "true";
        # proxy_set_header "Prerender-Disable-Ajax-Bypass" "true";
        # proxy_set_header "Prerender-Remove-Script-Tags" "true";
        # proxy_set_header "Prerender-Remove-Trailing-Slash" "true";
        # proxy_set_header "Prerender-Follow-Redirects" "true";

        # not recommended: read docs before enabling this
        # (if you do enable it, you'll have to adjust proxy_cache_key, at least)
        # proxy_set_header origin-header-whitelist prerendercloud-is-mobile-viewer;

        proxy_cache prerendercloud_cache;
        # this caches prerendercloud results for 5m
        proxy_cache_valid 200 5m;

        # don't let rate limiting or server errors interrupt a request
        proxy_intercept_errors on;
        error_page 429 500 502 503 504 =200 /index.html;

        # this serves stale while waiting on a request to service.headless-render-api.com to update cache (after 1st req)
        # see http://serverfault.com/questions/576402/nginx-serving-stale-cache-response-while-updating
        proxy_cache_use_stale updating;

        set $prerender 0;

        # RECOMMENDED DEFAULT CONFIG
        # only prerender if the path does not have an extension or does have an html extension
        # Note: this prerenders all user-agents, but the extension regex if statement
        #       is unnecessary (just conservative). The previous `location /` with a try_files for static resources
        #       is sufficient for preventing prerendering of static resources
        if ($uri ~ "^(([^.]|\.html?)+)$") {
            set $prerender "EXTENSION";
        }

        # ALL USER-AGENTS (RECOMMENDED)
        # (comment this out if using the "bots only section")
        set $prerender "${prerender}-USER_AGENT";

        # "BOTS ONLY" USER-AGENTS (NOT RECOMMENDED)
        # (comment this out if using the "all user-agents")
        # if ($http_user_agent ~* "googlebot|yahoo|bingbot|baiduspider|twitterbot|facebookexternalhit|rogerbot|linkedinbot|embedly|quora link preview|showyoubot|outbrain|pinterest|slackbot|vkShare|W3C_Validator|redditbot|Applebot|WhatsApp|flipboard|tumblr|bitlybot") {
        #     set $prerender "${prerender}-USER_AGENT";
        # }


        # don't prerender AJAX requests (optimization to avoid routing XHR/AJAX through service.headless-render-api.com)
        # see: https://github.com/sanfrancesco/prerendercloud-ajaxmonkeypatch#ajax-bypass
        if ($http_x_prerendered ~ true) {
            set $prerender 0;
            # Note: now your XHR origin will receive the x-prerendered header
            #       so if you use Access-Control-Allow-Headers from your XHR origin
            #       you have 3 options to avoid header warnings/errors
            #         1. either add x-prerendered to the whitelist (ideal)
            #         2. or if you're using nginx to proxy paths to different XHR origins,
            #            strip the header for that API proxy with: proxy_set_header x-prerendered "";
            #         3. if the above 2 options are untenable, you can disable this optimization
            #            by including the header: Prerender-Disable-Ajax-Bypass: true with your API requests
        }

        # don't prerender if the prerender user agent is retrieving the page
        if ($http_user_agent ~ "prerendercloud") {
            set $prerender 0;
        }

        # change this if you are using origin-header-whitelist or have other unique requirements
        # http://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache_key
        proxy_cache_key "$prerender$host$uri";

        if ($prerender = "EXTENSION-USER_AGENT") {
            # * non-standard ports will fail because request_uri drops the port (so only 80/443 will work)
            # * this particular configuration with the $uri variable in the proxy_pass is one of the few ways
            #   of preventing strange nginx URL re-encoding and decoding
            #     * https://stackoverflow.com/a/21012310
            #     * https://stackoverflow.com/a/37584637
            rewrite .* /$scheme://$host$request_uri? break;
            # The previous line is supposed to detect the scheme and host but
            # if this isn't working, just hard code your URL:
            # rewrite .* /https://www.example.com$request_uri? break;

            proxy_pass http://$prerendercloud$uri;
            break;
        }

        # forces non-existent files (404s) to load index.html (single page apps)
        rewrite .* /index.html break;
    }

}