how to download external files in gradle?

Question

I have a gradle project which requires some data files available somewhere on the internet using http. The goal is that this immutable remote file is pulled once upon first

Answer 1

The suggestion in Ben Manes's comment has the advantage that it can take advantage of maven coordinates and maven dependency resolution. For example, for downloading a Derby jar:

Define a new configuration:

configurations {
  derby
}

In the dependencies section, add a line for the custom configuration

dependencies {
  derby "org.apache.derby:derby:10.12.1.1"
}

Then you can add a task which will pull down the right files when needed (while taking advantage of the maven cache):

task deployDependencies() << {
   String derbyDir = "${some.dir}/derby"
   new File(derbyDir).mkdirs();
      configurations.derby.resolve().each { file ->
        //Copy the file to the desired location
        copy {
          from file 
          into derbyDir
          // Strip off version numbers
          rename '(.+)-[\\.0-9]+\\.(.+)', '$1.$2'
        }
      }
}

(I learned this from https://jiraaya.wordpress.com/2014/06/05/download-non-jar-dependency-in-gradle/).