How to get maven to build a war with minified file

Question

So I'm trying something I thought would be rather simple, I basically want maven to minify all my js and css files for me before building a war. My plugins look like this:

         <plugin>
            <groupId>org.apache.felix</groupId>
            <artifactId>maven-bundle-plugin</artifactId>
            <extensions>true</extensions>
            <version>1.0.0</version>
            <configuration>
                <manifestLocation>META-INF</manifestLocation>
                <instructions>
                    <Export-Package>!test.impl,test*</Export-Package>
                    <Import-Package>*</Import-Package>
                    <!--
                       add ,plugin.xml if it's present i.e.
                       src/main/resources,plugin.xml
                    -->
                    <Include-Resource>src/main/resources</Include-Resource>
                </instructions>
            </configuration>
        </plugin>

        <plugin>
            <groupId>net.alchim31.maven</groupId>
            <artifactId>yuicompressor-maven-plugin</artifactId>
            <version>1.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>compress</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <nosuffix>true</nosuffix>
            </configuration>
        </plugin>

The problem is that the YUI plugin does correctly minify the files, but just before the war is built it looks like it copies over all the files from my main source directory and thus wipes out the changes the YUI plugin had done.

I'm calling maven by the following: mvn compile war:war. I've been playing around for awhile with different settings, but so far I haven't found a way around this.

What I would like is for just after the war has copied over the files it needed from the src directory it would run the YUI plugin, but I tried all the permutations of phases on the YUI plugin, but that didn't seem to make any difference.

I've googled around, but pretty much everything I've read so far seems to indiciate that I should just need to drop the YUI plugin in there like I have and everything should magically work. So far I haven't seem to have found the magic.

Answer 1

as stated above maven-war-plugin overwrites files created by minify plugin. it seems that this cannot be changed. however wanted behavior may be achieved by simply changing project structure.

here example what I did with my project. I'm using minify-maven-plugin and spring framework, static files are stored in static directory.

1) move static directory from src/main/webapp to src/main/resources

2) change minify plugin config in pom.xml. so source points to resources and target points to classes:

<webappSourceDir>src/main/resources</webappSourceDir>
<webappTargetDir>target/classes</webappTargetDir>
<jsSourceDir>static</jsSourceDir>
<cssSourceDir>static</cssSourceDir>

3) change spring config. so spring is serving static files from class path:

<mvc:resources location="classpath:/static/" mapping="/static/**"/>

and now

mvn clean && mvn package

produces correct war with minified files inside /WEB-INF/classes/static

Answer 2

Use the war generator and add the configuration to exclude the sources file. Example:

    <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-war-plugin</artifactId>
            <version>${war-plugin.version}</version>
              <configuration> 
                <warSourceExcludes>js/**/*.js</warSourceExcludes> 
            </configuration> 
    </plugin>

After that you need to include your target files to your war. You do this by setting the "prepare-package" phase of maven lifecycle (I'm using Minify plugin) and adding the files on Minify configuration (jsSourceIncludes,cssSourceIncludes,...)

For example:

         <plugin>
            <groupId>com.samaxes.maven</groupId>
            <artifactId>minify-maven-plugin</artifactId>
            <version>1.7.2</version>
            <executions>
              <execution>
                <id>default-minify</id>
                <goals>
                    <goal>minify</goal>
                </goals>
               <phase>prepare-package</phase>
                <configuration>
                     <jsSourceDir>/js</jsSourceDir>
                     <jsSourceIncludes>
                        <jsSourceInclude>/**/*.js</jsSourceInclude>
                     </jsSourceIncludes>
                </configuration>
              </execution>
            </executions>
          </plugin>

Answer 3

You should take a look to Minify Maven Plugin which sounds like the thing you need.
Let me know if you need any help configuring it.

Answer 4

What happens is that the config above is running the compressor on the process-resources phase, but then the package phase overwrites these files with the original ones.

By changing the phase to package, it should work:

<execution>
    <phase>package</phase>
    <goals>
        <goal>compress</goal>
    </goals>

Now the compression is done after the files where copied to target in order to build the WAR content.

The reason why this is happening is that only compressing files without concatenating them or renaming them with a suffix is not the most common use case for the plugin.

Normally we want to compress and concatenate files into only one file, and give it a new name.

The new name is usually something like originalname-min.css / original.name-min.js where .min is the suffix, so removing the nosuffix option on the config above would also work.

Edit: Log example

[INFO] --- yuicompressor-maven-plugin:1.1:compress (default) @ yui-compressor-test -
[INFO] prettify.css (817b) -> prettify.css (617b)[75%]
[INFO] total input (1510b) -> output (1134b)[75%]

Answer 5

The accepted answer doesn't work.

Much better is this answer (as pointed out by koga in his comment): https://stackoverflow.com/a/11495021/11451

Here is what I ended up doing:

Step 1: minify the css and js

<plugin>
    <groupId>com.samaxes.maven</groupId>
    <artifactId>minify-maven-plugin</artifactId>
    <version>1.7.2</version>
    <executions>
        <execution>
            <phase>prepare-package</phase>
            <goals>
                <goal>minify</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <charset>UTF-8</charset>
        <skipMerge>true</skipMerge>
        <cssSourceDir>resources</cssSourceDir>
        <jsSourceDir>resources</jsSourceDir>
        <jsEngine>CLOSURE</jsEngine>
        <nosuffix>true</nosuffix>
        <webappTargetDir>${project.build.directory}/minify</webappTargetDir>
        <cssSourceIncludes>
            <cssSourceInclude>**/*.css</cssSourceInclude>
        </cssSourceIncludes>
        <cssSourceExcludes>
            <cssSourceExclude>**/*.min.css</cssSourceExclude>
        </cssSourceExcludes>
        <jsSourceIncludes>
            <jsSourceInclude>**/*.js</jsSourceInclude>
        </jsSourceIncludes>
        <jsSourceExcludes>
            <jsSourceExclude>**/*.min.js</jsSourceExclude>
        </jsSourceExcludes>
    </configuration>
</plugin>

Step 2: overwrite css and js in the war with minified files

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-war-plugin</artifactId>
    <version>2.4</version>
    <configuration>
        <webResources>
            <resource>
                <directory>${project.build.directory}/minify</directory>
            </resource>
        </webResources>
    </configuration>
</plugin>