Grails 3 - manipulating web.xml - grails

Question

As now web.xml will be generated dynamically, I'd need to add a simple filter class at the top of of it without writing or using a plugin.
What code would I need and where should I put it?
Or could I somehow get a template of what grails would generate for a web.xml and I could modify and override it?
I saw in the documentation
grails.war.resources = { stagingDir, args ->
copy(file: "grails-app/conf/custom-web.xml",
tofile: "${stagingDir}/WEB-INF/web.xml")
}
but first: would this function in application.yml?
and second: I'd still need an appropriate web.xml template to change...
Thanks!

Answer 1

From cfrick's suggestion, I tried this, (applies to grails 3)
Create a filter e.g. [grails-project]/src/main/java/hello/SimpleCORSFilter.java
(Create the 'java' directory, or create a SimpleCORSFilter.groovy in the [grails-project/src/main/groovy directory)
You can use the example in one of the spring guides.
package hello;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
#Component
public class SimpleCORSFilter implements Filter {
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletResponse response = (HttpServletResponse) res;
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
response.setHeader("Access-Control-Max-Age", "3600");
// response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
// I used this instead
response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
chain.doFilter(req, res);
}
public void init(FilterConfig filterConfig) {}
public void destroy() {}
}
Then in [grails-project]/grails-app/conf/spring/resources.groovy, add the filter, e.g.
import hello.SimpleCORSFilter
// Place your Spring DSL code here
beans = {
myFilter(SimpleCORSFilter)
}
Also, in the grails docs, to order your filter:
import hello.SimpleCORSFilter
import org.springframework.boot.context.embedded.FilterRegistrationBean
import org.springframework.core.Ordered
myFilter(FilterRegistrationBean) {
filter = bean(SimpleCORSFilter)
urlPatterns = ['/*']
order = Ordered.HIGHEST_PRECEDENCE
}

Answer 2

i know it's not the anwers to the actual question, but adding filters "springboot" style is just providing a #Bean for it. E.g. you can just put it in grails-app/conf/spring/resources.groovy. More details can be found at: How to add a filter class in Spring Boot?
Grails 3 embraces Springboot and with that came the good bye to XML based config (not saying it is forbidden, but its discouraged)

Answer 3

You can use install-templates command, which will copy templates to src/templates directory, there you will find web.xml template inside war directory, you can customize it
See http://www.grails.org/doc/latest/ref/Command%20Line/install-templates.html