Java/Tomcat-Jetty

How to install the Java Module

With Maven

Update your pom.xml file with the following content:

<project>
...
    <dependencies>
    ...
        <dependency>
          <groupId>co.datadome.module</groupId>
          <artifactId>datadome-java-module</artifactId>
          <version>1.14</version>
        </dependency>
    ...
    </dependencies>
...
</project>

Manual Installation

  1. Download and extract the archive:
wget https://package.datadome.co/linux/DataDome-Java-latest.tgz
tar zxvf DataDome-Java-latest.tgz
  1. The downloaded archive includes sources, so you can directly install it to your local Maven repository.

By default it is built with servlet-api-3.1. If your installation is dependant on servlet-api-3.0 or servlet-api-4.0, you need to build it manually with a different profile:

cd DataDome-JavaModuleDome-*
mvn install
cd DataDome-JavaModuleDome-*
mvn -P servlet-api-3.0 install
  1. Copy the target/datadome-java-module-xx.jar file to the server lib directory, similarly to the below:
/lib

Usage

The filter has been tested on Jetty, Tomcat and should work with Jboss as well as other servers supporting Servlet API.

🚧

Tomcat 8 or earlier

If you're using Tomcat (version 8 or earlier) as Java Servlet Container for your java application you should set the following Tomcat system property to true to enable the DataDome JAVA module to work properly:

org.apache.tomcat.util.http.ServerCookie.ALLOW_EQUALS_IN_VALUE=true

If this property is set to true, Tomcat will allow '=' characters when parsing unquoted cookie values. If false, cookie values containing '=' will be terminated when the '=' is encountered.

To set system property in Tomcat, you can modify your Tomcat start script and add a new system property to JAVA_OPTS.

Example :

export LANG="en_US.UTF-8"
export JAVA_OPTS="$JAVA_OPTS -Duser.language=en -Duser.country=US -Dorg.apache.tomcat.util.http.ServerCookie.ALLOW_EQUALS_IN_VALUE=true"
export CATALINA_PID=${CATALINA_HOME}/temp/tomcat.pid
export CATALINA_OPTS="$CATALINA_OPTS  -Xmx${JAVA_MAXMEMORY}m -DjvmRoute=${TOMCAT_JVM_ROUTE}  -Dtomcat.maxThreads=${TOMCAT_MAXTHREADS}  -Dtomcat.minSpareThreads=${TOMCAT_MINSPARETHREADS}  -Dtomcat.httpTimeout=${TOMCAT_HTTPTIMEOUT}  -Djava.security.egd=file:/dev/./urandom"

Explanation :

Tomcat (version 8 or earlier) uses legacy cookie processor (LegacyCookieProcessor) which implements a strict interpretation of the cookie specifications. Due to various interoperability issues with browsers, not all strict behaviors are enabled by default.

Refer to https://tomcat.apache.org/tomcat-8.0-doc/config/cookie-processor.html

Starting from version 9, Tomcat uses a more lenient cookie parser than the legacy one (Rfc6265CookieProcessor) by default. In particular:

  • The '=' and '/' characters are always permitted in a cookie value.

Refer to https://tomcat.apache.org/tomcat-9.0-doc/config/cookie-processor.html

To use the filter you need to add it to web.xml as first server.

Example:

<web-app>
...
    <filter>
        <filter-name>datadome-filter</filter-name>
        <filter-class>co.datadome.api.servlet.DataDomeFilter</filter-class>
        <init-param>
            <param-name>datadome.apikey</param-name>
            <param-value>YOUR_SECRET_LICENSE_KEY</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>datadome-filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
...
</web-app>

You can also specify additional parameters likes hostname or timeout.

List of possible init parameters:

Settings

Description

Default

datadome.apikey

License key to access API

datadome.hostname

API server's hostname
Available endpoints

api.datadome.co

datadome.ssl

Use SSL between the filter and the API server

true

datadome.regex

Inclusion Regex

""

datadome.exclusion_regex

Exclusion Regex

\.(js|css|jpg|jpeg|png|ico|gif|tiff|svg|woff|woff2|ttf|eot|mp4|otf)$

datadome.connection_timeout

Connection timeout (in ms)

150

datadome.read_timeout

Read timeout (in ms)

50

datadome.max_connections

Maximum open connections to the API server

100

datadome.proxy_server

Host that will be used as proxy server
See here

datadome.proxy_port

TCP port at the proxy server
See here

datadome.proxy_ssl

Is the connection to the proxy established through TLS
See here

false

datadome.skip_ips

IPv4 or IPv6 subnetwork list on which datadome validation is not executed, e.g.: "2a03:2880:1000::/36,124.66.0.0/17"

You can use environment variables inside the DataDome filter's param-value.

For example, if you have the system environment variable DATADOME_API_KEY with your API key, you can input it in web.xml as follows:

<init-param>
            <param-name>datadome.apikey</param-name>
            <param-value>${DATADOME_API_KEY}</param-value>
        </init-param>

FAQ

How can I log the time spent calling DataDome API?

The DataDome filter adds the attribute datadome.spent_time (number of milliseconds spent for building request/getting response from DataDome API) so it could be easily retrieved inside your servlet.

Here is how you can use it:

@Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().println("Example servlet");
        System.out.println("Time spent by DataDome:" + req.getAttribute("datadome.spent_time"));
        resp.setStatus(200);
    }

Note: the above example is for demonstration purposes only.
Your use case could be different, such as sending spent_time value to your monitoring system, etc.

Can DataDome API be called via outbound proxy?

The DataDome module can be used with outbound proxy. Two options are available for proxy configuration:

  • Use system settings such as -Dhttp.proxyHost=1.2.3.4 -Dhttp.proxyPort=8080 -Dhttps.proxyHost=1.2.3.4 -Dhttps.proxyPort=8443 when running your java application.

  • Use optional DataDome init parameters datadome.proxy_server, datadome.proxy_port, datadome.proxy_ssl in web.xml.

Note: using the DataDome module with outbound proxy can slow down the total time spent calling DataDome API and increase timeouts. Please adjust timeout settings accordingly.