Find if an artifact exists in remote repository

Question

How do I check if an artifact exists in a remote repository using gradle?

I haven't been able to find any plugins for gradle that accomplish this.

I've had an idea of creating a function in build.gradle that checks if the url of the repository exists. But this doesn't seem like the right way of doing it.

Boolean ifExists = new URL(url).openConnection().with {
        requestMethod = 'HEAD'
        connect()
        responseCode == 200
}

Any suggestions would be much appreciated.

Answer 1

Using Kotlin DSL you may check if the artifact exists in any of registered repositories in the following way:

import com.github.kittinunf.fuel.httpGet

buildscript {
    dependencies {
        "classpath"("com.github.kittinunf.fuel:fuel:2.3.1") // you may use any other HTTP-client if you want
    }
}

tasks {
    register("checkDependencies") {
        doFirst {
            project.configurations["implementation"].dependencies.forEach { dependency ->
                project.repositories.forEach { repository ->
                    val repositoryURL = (repository as MavenArtifactRepository).url
                    val artifactURL = "$repositoryURL${dependency.group?.replace('.', '/')}/${dependency.name}/${dependency.version}/${dependency.name}-${dependency.version}.jar"
                    val (_, response, _) = artifactURL.httpGet().response()
                    println("$dependency: ${response.statusCode}")
                }
            }
        }
    }
}

Answer 2

It doesn't appear there is an official Gradle plugin to support checking for an artifact's existence. However, you should be able to accomplish this by executing a curl command in a Java process: Curl flags explanation:

-I flag for headers only.

-s for silent mode. (No prog meter or error messages)

Your command may look slightly different than the one below if you need to authenticate to the artifact resource, but I am assuming you have already accounted for that in your url:

String curlCommand= "curl -I -s " + url + " | grep HTTP";
Process process = Runtime.getRuntime().exec(curlCommand);
process.getInputStream();

If your artifact is found, the process will print "HTTP/1.1 200 OK"

Otherwise, "HTTP/1.1 404 Not Found"