data-uri function not working

[ILadis]

Hey,

I'm using your plugin to compile my Less sources. I tried to make use of the data-uri function (docs see here) that Less provides, but I could not get it working. The plugin keeps on throwing the following error:

[ERROR] Failed to execute goal biz.gabrys.maven.plugins:lesscss-maven-plugin:1.2.0:compile (default) on project ...: RuntimeError: error evaluating function `data-uri`: Cannot find module './fs' in .../gabrys-biz-lesscss-maven-plugin/styles.less-n1871238842.source.code on line 5

The line (5) the error message is refering to is the exact position in my Less file where I used the data-uri function.

I invastigated the issue and came to the following solution:

1. Fixing: Cannot find module './fs'

This issue lies in your lesscss-compiler project, more specifically in less-rhino-1.7.5.js. The fs module is defined, but requiring it via require('./fs') is simply not working. When invoking the stubbed require function with a module containing a / the implementation will not look in less.modules (where the fs module is defined). Therefore changing require('./fs') to require('fs') (see position in code less-rhino-1.7.5.js:2679) will resolve this issue.

2. Fixing: Cannot convert org.mozilla.javascript.NativeArray to byte[]

When (1) was fixed I instead got a similar issue as described here. To fix this issue I had to make changes to the encodeBase64String(String) (see position in code less-rhino-1.7.5.js:143. I changed the encodeBase64String(String) like this:

function encodeBase64Bytes(bytes) {
  var array = java.lang.reflect.Array.newInstance(java.lang.Byte.TYPE, bytes.length);
  for (var index = 0; index < bytes.length; index++) {
    var oneByte = bytes[index];
    if (oneByte > 127) {
      oneByte -= 256;
    }
    array[index] = oneByte;
  }
  // requires at least a JRE Platform 6 (or JAXB 1.0 on the classpath)
  return javax.xml.bind.DatatypeConverter.printBase64Binary(array);
}

After those two fixes I was able to use the data-uri function. One still has to tell the maven plugin where to find the resources to be data-uri'ed by either using absolute paths or placing the resources inside target/gabrys-biz-lesscss-maven-plugin.

Is there any chance the data-uri function will be fixed in a future version? I could also send a pull request with my fix, if you wish.

[agabrys]

Hi,
Thank you for noting that 😄
You can prepare a PR or I will add/copy you changes. Have you got any test project for this issue? I want to test it before release 😉

[ILadis]

Thanks for replying!

I attached a ZIP archive (test-project.zip) containing a very simple maven project that is using your lesscss-maven-plugin in the current version 1.2.0. If you run mvn compile on the project root directory, you will get the error I described above.

I also attached my fix (less-rhino-1.7.5.txt, rename it to less-rhino-1.7.5.js) for this issue. Once you built a new version of the lesscss-compiler and lesscss-maven-plugin the example project should compile without any errors.
You can use the index.html in my sample project to check whether the image got data-uri'ed successfully.

[agabrys]

I tested your solution and it works. The only problem is that resources paths must be relative to working directory... Unfortunately it will be difficult to fix it. I have an idea (a new vision for LessCSS Compiler library) but I need to consult it with one colleague from my work.

For now you can use workaround:

1. add sonatype-nexus-snapshots repository to pom.xml file:

<repositories>
    <repository>
        <id>sonatype-nexus-snapshots</id>
        <name>Sonatype's SNAPSHOT repository</name>
        <url>https://oss.sonatype.org/content/repositories/snapshots</url>
        <releases>
            <enabled>false</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>

2. add biz.gabrys.lesscss:compiler:1.2.2-SNAPSHOT dependency to lesscss-maven-plugin:

<plugin>
    <groupId>biz.gabrys.maven.plugins</groupId>
    <artifactId>lesscss-maven-plugin</artifactId>
    <version>1.2.0</version>
    <dependencies>
        <dependency>
            <groupId>biz.gabrys.lesscss</groupId>
            <artifactId>compiler</artifactId>
            <version>1.2.2-SNAPSHOT</version>
        </dependency>
    </dependencies>
    <executions>
        <execution>
            ...
        </execution>
    </executions>
</plugin>

3. change lesscss-maven-plugin compiler type form full to local:

<executions>
    <execution>
        <goals>
            <goal>compile</goal>
        </goals>
        <configuration>
            <compilerType>local</compilerType>
            ...
        </configuration>
    </execution>
</executions>

[ILadis]

Thanks for looking into my solution!

I will give feedback on your workaround as soon as I am able to try it out. It's currently not super urgent to have a fixed and running version of the Less compiler for my project.

But I am still looking forward to use the fixed Less Compiler on it's next official release without the need of any workarounds.

[agabrys]

Ok. I fixed (with your help 😄) support for data-uri function, but (for now) only for local compiler. If you don't import files located in Internet or classpath then you can use:

<plugin>
    <groupId>biz.gabrys.maven.plugins</groupId>
    <artifactId>lesscss-maven-plugin</artifactId>
    <version>1.2.1</version>
    <executions>
        <execution>
            <goals>
                <goal>compile</goal>
            </goals>
            <configuration>
                <compilerType>local</compilerType>
                ...
            </configuration>
        </execution>
    </executions>
</plugin>

[ILadis]

Hey,
thank you so much for fixing the data-uri function. I just gave the new version a try and it works like a charm!

Thanks for fixing it so quickly!