WordPress 的四层缓存分别解决哪种慢，按什么顺序配（附可跑的 Nginx 与 WP-CLI 步骤）

for i in 1 2 3 4 5; do
  curl -o /dev/null -s -w 'ttfb:%{time_starttransfer} total:%{time_total}\n' https://example.com/
done

server {
    # 加在已有的 server 块里
    location ~* \.(css|js|png|jpe?g|gif|webp|avif|svg|ico|woff2?|ttf|otf)$ {
        add_header Cache-Control "public, max-age=2592000" always;
        access_log off;
        try_files $uri =404;
    }
}

curl -sI https://example.com/wp-content/themes/your-theme/style.css | grep -i cache-control

curl -sI https://example.com/wp-content/uploads/2026/01/pic.jpg | grep -i age
sleep 3
curl -sI https://example.com/wp-content/uploads/2026/01/pic.jpg | grep -i age

fastcgi_cache_path /var/cache/nginx/wp levels=1:2 keys_zone=wp_cache:100m max_size=2g inactive=60m use_temp_path=off;
fastcgi_cache_key "$scheme$request_method$host$request_uri";

# 带这些 cookie 的请求不缓存
map $http_cookie $skip_cookie {
    default 0;
    "~*wordpress_logged_in"       1;
    "~*comment_author"            1;
    "~*wp-postpass"               1;
    "~*woocommerce_items_in_cart" 1;
    "~*woocommerce_cart_hash"     1;
    "~*wp_woocommerce_session"    1;
}

# 只缓存 GET / HEAD
map $request_method $skip_method {
    default 1;
    GET     0;
    HEAD    0;
}

# 这些路径不缓存
map $request_uri $skip_uri {
    default 0;
    "~*/wp-admin/"      1;
    "~*/wp-login\.php"  1;
    "~*/cart/"          1;
    "~*/checkout/"      1;
    "~*/my-account/"    1;
    "~*preview=true"    1;
    "~*[?&]s="          1;
}

# 三个条件拼起来，任何一个为 1 就跳过缓存
map "$skip_cookie$skip_method$skip_uri" $skip_cache {
    default 0;
    "~1"    1;
}

location ~ \.php$ {
    include fastcgi_params;
    fastcgi_pass unix:/run/php/php-fpm.sock;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;

    fastcgi_cache wp_cache;
    fastcgi_cache_valid 200 301 302 10m;
    fastcgi_cache_valid 404 1m;
    fastcgi_cache_bypass $skip_cache;
    fastcgi_no_cache     $skip_cache;
    fastcgi_cache_lock   on;
    fastcgi_cache_use_stale error timeout updating http_500 http_503;
    fastcgi_cache_background_update on;

    add_header X-Cache $upstream_cache_status always;
}

# Debian/Ubuntu 是 www-data，CentOS/RHEL 是 nginx
sudo mkdir -p /var/cache/nginx/wp
sudo chown www-data:www-data /var/cache/nginx/wp
sudo nginx -t && sudo systemctl reload nginx

curl -sI https://example.com/ | grep -i x-cache   # 第一次：MISS
curl -sI https://example.com/ | grep -i x-cache   # 第二次：HIT
curl -sI -H 'Cookie: wordpress_logged_in_abc=1' https://example.com/ | grep -i x-cache   # 应为 BYPASS

sudo find /var/cache/nginx/wp -type f -delete

wp eval 'global $wpdb; echo "queries: ", $wpdb->num_queries, "\n";'

# 第一个进程写入
wp eval 'wp_cache_set("probe", "1", "aumtest"); echo "set ok\n";'

# 第二个进程读取
wp eval 'var_dump(wp_cache_get("probe", "aumtest"));'