Home/ Questions/Q 848213
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-15T06:54:28+00:00

I’ve created a groovlet that will act as a sort of HTTP proxy. It

  • 0

I’ve created a groovlet that will act as a sort of HTTP proxy. It accepts GET requests and then makes web service calls based on the URL provided in the request.

Here’s the code I’ve got so far:

@Grab(group='org.codehaus.groovy.modules.http-builder', module='http-builder', version='0.5.0')
import groovyx.net.http.*
import static groovyx.net.http.ContentType.*
import static groovyx.net.http.Method.*

String url = params.url

def http = new HTTPBuilder(url)

http.request(GET, TEXT) {

     response.success = { resp, reader ->
       println reader
     }

     response.'404' = { resp -> 
       println 'not found!'
     }
}

I’ve got the Groovy HTTPBuilder JAR file in the WEB-INF/lib folder of the groovlet. However, the code isn’t working as it should. (I also tried putting the folder in $TOMCAT_HOME/common/lib with the same results as below.)

When I run the code exactly as it is above, the page comes back completely blank.

If I remove just the @Grab line at the top (since the JAR should theoretically be in the classpath already), I get a nasty error from Tomcat (I’m running it on 5.5, but I get roughly the same behavior on 6):

HTTP Status 500 – GroovyServlet Error:
script: ‘/proxy.groovy’: Script
processing failed.startup failed:
General error during semantic
analysis: Type
org.apache.http.client.methods.HttpRequestBase
not present
java.lang.TypeNotPresentException:
Type
org.apache.http.client.methods.HttpRequestBase
not present…

That is then followed by the stack trace.

What is wrong with my groovlet?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Two things.

    First, it seems that Groovlets can’t use Grape (the @Grab command). That’s why the groovlet fails silently when this line is present.

    Second, the http-builder module also depends on about 19 other packages (including the org.apache.http.client.methods.HttpRequestBase that is referenced in the error message). You can find these packages in the ~/.groovy/grapes folder.

    If you want to find all the dependencies, delete the Grapes directory. Then run a script locally that uses that @Grab command. Once the script has finished executing, you can look in the Grapes directory and see everything it downloaded.

    When I did it, I got the following list of packages:

    antlr
asm
commons-beanutils
commons-codec
commons-collections
commons-lang
commons-logging
net.sf.ezmorph
net.sf.json-lib
net.sourceforge.nekohtml
org.apache
org.apache.commons
org.apache.httpcomponents
org.codehaus.groovy
org.codehaus.groovy.modules.http-builder
xerces

    So if you want to use HttpBuilder in a groovlet, you’ll need to get all those dependencies in WEB-INF/lib or your Tomcat common/lib directory.

    On the other hand, if you don’t need anything terribly fancy, you can use the Groovy URL object. See some examples here.

    • 0