org.javalite.activeweb.controllers.AbstractSASSController Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of activeweb Show documentation
Core functionality of the framework
The newest version!
package org.javalite.activeweb.controllers;

import org.javalite.activeweb.AppController;
import org.javalite.common.Util;

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import static java.lang.Runtime.getRuntime;
import static org.javalite.common.Util.read;

/**
 * 
 * Subclass will compile and serve CSS from SASS files.
 * For more information on SASS, please see https://sass-lang.com/.
 * Usually a developer would subclass this controller to trigger and compile in development environment,
 * but the URI to CSS file would be ignored by the framework (configured in RouteConfig), so that a statically
 * compiled version is served by a container or a web server.
 * 
 * 
 * This controller does not by itself compile SASS files. It shells out to a sass compiler, which
 * needs to be installed.
 * 
 * 
 * The controller will only compile SASS files if there have been any changes since the last invocation.
 * If there has been no changes, it immediately serves the cached version of CSS compiled previously.
 * 
 * Example usage:
 *  *
 * public class BootstrapController extends AbstractSASSController {
        protected File getSASSFile() {
            return new File("src/main/webapp/sass/bootstrap.sass");
        }
    }
 ...

   public class RouteConfig extends AbstractRouteConfig {
      public void init(AppContext appContext) {
           ignore("/bootstrap.css").exceptIn("development");
      }
 * }
 * 
 * The line in the RouteConfig ensures that the URI /bootstrap.css is ignored by the framework
 * in every environment except "development". This is why the controller is triggering in development environment only.
 *
 * @author igor on 4/28/14
 */
public abstract class AbstractSASSController extends AppController {

    public void index() {
        try {
            respond(css()).contentType("text/css");
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * Subclass should return a file handle pointing to the main SASS file.
     * @return file handle pointing to the main SASS file
     */
    protected abstract File getSASSFile();


    /**
     * Subclass should override this method if they want to provide custom list of arguments to SASS compiler.
     *
     * @return custom list of arguments for SASS compiler.
     */
    protected String[] getSASSArguments(){
        return null;
    }


    private synchronized String css() throws Exception {
        File sassFile = getSASSFile();
        if (!sassFile.exists()) {
            throw new RuntimeException("File: " + sassFile.getPath() + " does not exist. Current directory: " + new File(".").getCanonicalPath());
        }
        String hash = (String) appContext().get("hash");
        String freshHash = getDirectoryHash(sassFile.getParentFile().getPath());

        if (hash != null && hash.equals(freshHash)) {
            return (String) appContext().get("css"); // no changes
        } else {
            String css = sass(sassFile, getSASSArguments());
            appContext().set("hash", freshHash);
            appContext().set("css", css);
            return css;
        }
    }



    private String sass(File sassFile, String... arguments) throws IOException, InterruptedException {

        String command = "sass";
        if (System.getProperty("os.name").toLowerCase().contains("windows")) {
            command += ".cmd";
        }

        String[] commandArray;
        if (arguments != null) {
            logInfo("Executing: " + "sass " + Util.join(arguments, " ") + " " + sassFile.getPath());
            commandArray = new String[arguments.length + 2];
            commandArray[0] = command;
            System.arraycopy(arguments, 0, commandArray, 1, arguments.length);
            commandArray[commandArray.length - 1] = sassFile.getPath();
        }else{
            logInfo("Executing: " + "sass "  + sassFile.getPath());
            commandArray = new String[2];
            commandArray[0] = command;
            commandArray[1] = sassFile.getPath();
        }

        Process process = getRuntime().exec(commandArray);
        String css = read(process.getInputStream(), "UTF-8");
        String error = read(process.getErrorStream(), "UTF-8");
        if (process.waitFor() != 0) {
            throw new RuntimeException(error);
        }
        return css;
    }

    private String getDirectoryHash(String directory) throws NoSuchAlgorithmException {
        StringBuilder code = new StringBuilder();
        File[] list = new File(directory).listFiles();
        if (list == null)
            return null;

        for (File f : list) {
            if (f.isDirectory()) {
                code.append(f.getName()).append(f.length()).append(f.lastModified()).append(getDirectoryHash(f.getAbsolutePath()));
            } else {
                code.append(f.getName()).append(f.length()).append(f.lastModified());
            }
        }
        return new String(MessageDigest.getInstance("MD5").digest(code.toString().getBytes(StandardCharsets.UTF_8)));
    }
}