## ngx_http_js_challenge_module
[](https://www.codefactor.io/repository/github/simon987/ngx_http_js_challenge_module)
[Demo website](https://ngx-js-demo.simon987.net/)
Simple javascript proof-of-work based access for Nginx with virtually no overhead.
Easy installation: just add `load_module /path/to/ngx_http_js_challenge_module.so;` to your
`nginx.conf` file and follow the [configuration instructions](#configuration).
### Configuration
**Simple configuration**
```nginx
server {
js_challenge on;
js_challenge_secret "change me!";
# ...
}
```
**Advanced configuration**
```nginx
server {
js_challenge on;
js_challenge_secret "change me!";
js_challenge_html /path/to/body.html;
js_challenge_bucket_duration 3600;
js_challenge_title "Verifying your browser...";
location /static {
js_challenge off;
alias /static_files/;
}
location /sensitive {
js_challenge_bucket_duration 600;
#...
}
#...
}
```
* `js_challenge on|off` Toggle javascript challenges for this config block
* `js_challenge_secret "secret"` Secret for generating the challenges. DEFAULT: "changeme"
* `js_challenge_html "/path/to/file.html"` Path to html file to be inserted in the `` tag of the interstitial page
* `js_challenge_title "title"` Will be inserted in the `` tag of the interstitial page. DEFAULT: "Verifying your browser..."
* `js_challenge_bucket_duration time` Interval to prompt js challenge, in seconds. DEFAULT: 3600
### Installation
1. Add `load_module ngx_http_js_challenge_module.so;` to `/etc/nginx/nginx.conf`
1. Reload `nginx -s reload`
### Build from source
These steps have to be performed on machine with compatible configuration (same nginx, glibc, openssl version etc.)
1. Install dependencies
```bash
apt install libperl-dev libgeoip-dev libgd-dev libxslt1-dev libpcre3-dev
```
2. Download nginx tarball corresponding to your current version (Check with `nginx -v`)
```bash
wget https://nginx.org/download/nginx-1.16.1.tar.gz
tar -xzf nginx-1.16.1.tar.gz
export NGINX_PATH=$(pwd)/nginx-1.16.1/
```
3. Compile the module
```bash
git clone https://github.com/simon987/ngx_http_js_challenge_module
cd ngx_http_js_challenge_module
./build.sh
```
4. The dynamic module can be found at `${NGINX_PATH}/objs/ngx_http_js_challenge_module.so`
### Known limitations / TODO
* Users with cookies disabled will be stuck in an infinite refresh loop (TODO: redirect with a known query param, if no cookie is specified but the query arg is set, display an error page)
* If nginx is behind a reverse proxy/load balancer, the same challenge will be sent to different users and/or the response cookie will be invalidated when the user is re-routed to another server. (TODO: use the x-real-ip header when available)