<when_to_use>
Load this skill when querying a web.xml deployment descriptor — enumerating servlets, inspecting filter chains, listing listeners, extracting context parameters, or finding servlets by init-param value.
</when_to_use>
Domain skill for querying Tomcat web.xml files using dasel v3. Always use -i xml explicitly. XML attributes use - prefix in dasel friendly mode.
Servlet Discovery
# All servlet names
cat web.xml | dasel -i xml 'web-app.servlet.map(servlet-name)'
# Count servlet definitions
cat web.xml | dasel -i xml 'len(web-app.servlet)'
Filter Chain Analysis
# Find filters by class pattern (e.g., Security filters)
cat web.xml | dasel -i xml 'web-app.filter.filter(filter-class ~ ".*Security.*")'
Replace Security with any class name fragment.
Listener Enumeration
# Count listener definitions
cat web.xml | dasel -i xml 'len(web-app.listener)'
Context Parameters
# All context-param names
cat web.xml | dasel -i xml 'web-app.context-param.map(param-name)'
Init Parameter Inspection
# Find servlets with a specific init-param name — filters parent collection by testing child length > 0
cat web.xml | dasel -i xml 'web-app.servlet.filter(init-param.filter(param-name == "debug").len($this) > 0).map(servlet-name)'
Replace "debug" with the target param-name value.
All selectors require the full command prefix: cat web.xml | dasel -i xml '<selector>'