Troubleshooting

Why is $device_type returning an empty value?

If the $device_type variable is returning an empty value, it is likely that the device-type module is not loaded correctly. This module must be loaded dynamically and explicitly in the NGINX configuration.

To fix this, ensure that the module is loaded at the top of your nginx.conf file. Add the following line if it is missing:

load_module modules/ngx_http_device_type_module.so;

After making this change, reload NGINX to apply the configuration.

Why does $is_mobile return 1 for tablets?

The $is_mobile variable is designed to identify mobile devices, which can sometimes include tablets depending on the user agent string. This behavior is due to the regex patterns used for detection, which may classify certain tablets as mobile devices.

To address this, use the $is_tablet variable in conjunction with $is_mobile to differentiate between mobile phones and tablets:

if ($is_mobile) {
    if ($is_tablet) {
        # Handle tablet-specific logic
    } else {
        # Handle mobile phone-specific logic
    }
}

Why are client hints not respected?

The device-type module supports Client Hints, but they must be enabled and correctly configured in both the client and server. Ensure that your server is set up to accept and process Client Hints headers like Sec-CH-UA, Sec-CH-UA-Mobile, and Sec-CH-UA-Platform.

Check your NGINX configuration to ensure that these headers are being passed to your server:

proxy_set_header Sec-CH-UA $http_sec_ch_ua;
proxy_set_header Sec-CH-UA-Mobile $http_sec_ch_ua_mobile;
proxy_set_header Sec-CH-UA-Platform $http_sec_ch_ua_platform;

How to improve regex performance for device detection?

The device-type module uses over 3,600 regex patterns for device detection, which can impact performance. To optimize this, ensure that PCRE JIT (Just-In-Time) compilation is enabled in your NGINX configuration.

Add the following directive at the top level of your nginx.conf:

pcre_jit on;

This will help improve the performance of regex operations by compiling them into machine code.

Why are some bots not detected as AI crawlers?

The module includes detection for over 50 AI bots, but new bots may not be recognized if they are not included in the current regex patterns. If a known AI bot is not detected, it might be due to an outdated module version or missing patterns.

Ensure you are using the latest version of the device-type module. If the issue persists, consider contacting the module vendor for updates or support.