My ant build target for building and uploading xar from project folder.

gistfile1.xml

<target name="xar-build-upload" >
    <buildnumber file="build.version"/>
    <property name="project.version" value="${version.major}.${build.number}"/>
    <property name="xar-location" value="${dir.project}/${dir.build}/${project.abbrev}-${project.version}.xar"/>
    <property name="repo.url" value="http://${host.local}:8080/exist/apps/public-repo/public/"/>
    <property name="repo.update" value="http://${host.local}:8080/exist/apps/public-repo/modules/update.xql"/>
    <property name="xar-file" value="${project.abbrev}-${project.version}.xar"/>

    <echo>project.version:  ${project.version}</echo>
    <antcall target="deployment-folder"/>
    <antcall target="eXist-data"/>
    <antcall target="build-xar"/>

    <exec executable="curl">
        <arg line="-T ${xar-location} -u ${exist.username}:${exist.password} ${repo.url}/${xar-file}"/>
    </exec>

    <exec executable="curl">
        <arg line="-G -u ${exist.username}:${exist.password} ${repo.update}"/>
    </exec>

<property name="install-and-deploy">
xquery version "3.0";
import module namespace repo="http://exist-db.org/xquery/repo";
repo:install-and-deploy("http://${project.domain}", "http://${host.local}:8080/exist/apps/public-repo/modules/find.xql")
</property>

<xdb:xquery  xmlns:xdb="http://exist-db.org/ant"
    uri="${local.url}/db"
    query="${install-and-deploy}"
    user="${exist.username}" password="${exist.password}"/>

<antcall target="browse"/>
</target>