Gradle plugin copy file from plugin jar - plugins

Question

I'm creating my first gradle plugin. I'm trying to copy a file from the distribution jar into a directory I've created at the project. Although the file exists inside the jar, I can't copy it to the directory.
This is my task code:
import org.gradle.api.DefaultTask;
import org.gradle.api.tasks.TaskAction;
class InitTask extends DefaultTask {
File baseDir;
private void copyEnvironment(File environments) {
String resource = getClass().getResource("/environments/development.properties").getFile();
File input = new File(resource);
File output = new File(environments, "development.properties");
try {
copyFile(input, output);
}
catch (IOException e) {
e.printStackTrace();
}
}
void copyFile(File sourceFile, File destFile) {
destFile << sourceFile.text
}
#TaskAction
void createDirectories() {
logger.info "Creating directory."
File environments = new File(baseDir, "environments");
File scripts = new File(baseDir, "scripts");
File drivers = new File(baseDir, "drivers");
[environments, scripts, drivers].each {
it.mkdirs();
}
copyEnvironment(environments);
logger.info "Directory created at '${baseDir.absolutePath}'."
}
}
And this is the error I'm getting:
:init
java.io.FileNotFoundException: file:/path-to-jar/MyJar.jar!/environments/development.properties (No such file or directory)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:120)
at groovy.util.CharsetToolkit.<init>(CharsetToolkit.java:69)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.newReader(DefaultGroovyMethods.java:15706)
at org.codehaus.groovy.runtime.DefaultGroovyMethods.getText(DefaultGroovyMethods.java:14754)
at org.codehaus.groovy.runtime.dgm$352.doMethodInvoke(Unknown Source)
at org.codehaus.groovy.reflection.GeneratedMetaMethod$Proxy.doMethodInvoke(GeneratedMetaMethod.java:70)
at groovy.lang.MetaClassImpl$GetBeanMethodMetaProperty.getProperty(MetaClassImpl.java:3465)
at org.codehaus.groovy.runtime.callsite.GetEffectivePojoPropertySite.getProperty(GetEffectivePojoPropertySite.java:61)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGetProperty(AbstractCallSite.java:227)
at br.com.smartcoders.migration.tasks.InitTask.copyFile(InitTask.groovy:29)
Just to emphasize, the development.properties is inside the environments directory inside the MyJar.jar

Answer 1

getClass().getResource() returns a URL. To access that URL, you'll have to read it directly (e.g. with url.text) rather than first converting it to a String/File. Or you can use getClass().getResourceAsStream().text, which is probably more accurate. In both cases you can optionally specify the file encoding.

Answer 2

Kotlin DSL answer!
For cases like this it is good to have extensions:
fun Any.getResource(filename: String): File? {
val input = this::class.java.classLoader.getResourceAsStream(filename) ?: return null
val tempFile = File.createTempFile(
filename.substringBeforeLast('.'),
"." + filename.substringAfterLast('.')
)
tempFile.deleteOnExit()
tempFile.writer().use { output ->
input.bufferedReader().use { input ->
output.write(input.readText())
}
}
return tempFile
}