Maven Support

[nikhedonia]

Buck supports Java and downloads from Maven.

remote_file(
  name = 'httpmime-jar',
  sha1 = '54ffde537682aea984c22fbcf0106f21397c5f9b',
  url = 'mvn:org.apache.httpcomponents:httpmime:jar:4.3.4',
  out = 'httpmime.jar',
)

To implement Maven support, Buckaroo would need:

1. to be able to parse maven uri's
2. find and parse pom.xml manifest from maven
3. fetch transitive dependencies
4. generate an appropriate buck file on install

[nikhedonia]

Some more info:
A maven repository has a predictable file-structure:
http://central.maven.org/maven2/

A maven coordonate eg. com.google.guava:guava maps to
http://central.maven.org/maven2/com/google/guava/guava

This folder contains several important files:

A listing of all available versions:
http://central.maven.org/maven2/com/google/guava/guava/maven-metadata.xml

<metadata modelVersion="1.1.0">
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <versioning>
    <latest>27.1-jre</latest>
    <release>27.1-jre</release>
    <versions>
      <version>r03</version>
      <version>22.0-rc1-android</version>
      <version>18.0-android</version>
      <version>18.0-jre</version>
...

And foreach version eg. http://central.maven.org/maven2/com/google/guava/guava/22.0-rc1-android

the artefact:
http://central.maven.org/maven2/com/google/guava/guava/22.0-rc1-android/guava-22.0-rc1-android.jar

And the Manifest:
http://central.maven.org/maven2/com/google/guava/guava/22.0-rc1-android/guava-22.0-rc1-android.pom

Which includes a list of dependencies:

<dependencies>
  <dependency>
    <groupId>com.google.code.findbugs</groupId>
    <artifactId>jsr305</artifactId>
  </dependency>
  <dependency>
    <groupId>com.google.errorprone</groupId>
    <artifactId>error_prone_annotations</artifactId>
  </dependency>
  <dependency>
     <groupId>org.codehaus.mojo</groupId>
     <artifactId>animal-sniffer-annotations</artifactId>
     <version>${animal.sniffer.version}</version>
   </dependency>

Some of the entries may refer to properties:

 <properties>
    <aaa.bbb.ccc>1.7</aaa.bbb.ccc>
  </properties>

Every file also has a corresponding .sha1:
http://central.maven.org/maven2/com/google/guava/guava/22.0-rc1-android/guava-22.0-rc1-android.jar.sha1

• How to wire up Maven with the Resolver:

1. Define a Maven PackageIdentifer & Location
   • https://github.com/LoopPerfect/buckaroo/blob/master/buckaroo/PackageIdentifier.fs#L7
   • https://github.com/LoopPerfect/buckaroo/blob/master/buckaroo/PackageLocation.fs#L24
2. Create a Maven Coordiate Parser
   • https://github.com/LoopPerfect/buckaroo/blob/master/buckaroo/PackageIdentifier.fs#L91
3. Create a POM to Manifest translator
   • implement a function that maps maven-location to pom url
   • switch on location type fetch and translate file here: https://github.com/LoopPerfect/buckaroo/blob/master/buckaroo/DefaultSourceExplorer.fs#L295

• How to wire things up with Buck:

0. download artefact into cache folder
1. copy artefact from cache folder to buckaroo/central/maven/org/maven2/com/google/guava/guava/22.0-rc1-android/

generate a BUCK file:

load('//buckaroo_macros.bzl', 'buckaroo_deps')
prebuilt_jar(
  name = 'guava-22.0-rc1-android-prebuilt',
  binary_jar = 'guava-22.0-rc1-android.jar',
  source_jar = 'guava-22.0-rc1-android.sources.jar', # optional
  javadoc_url = 'http://kentbeck.github.com/junit/javadoc/4.8/', # optional
)

java_library(
  name = 'guava-22.0-rc1-android',
  visibility = ['PUBLIC'],
  deps = buckaroo_deps()
)

https://buckbuild.com/rule/prebuilt_jar.html