Tapestry 4:资产缓存控制?

在对这个问题苦思冥想了很长时间后,我最终自己解决了它。此解决方案假定您具有 tapestry-spring library 在你的项目中。

在我的例子中,我有一个Springbean,它包含我的应用程序的一些全局属性:

package myapp;

public class AppProperties {
    private String build;

    public String getBuild() {
        return build;
    }

    public void setBuild(String build) {
        this.build = build;
    }

    // other properties
}

在Spring配置中声明此bean:

<bean id="appProperties" class="myapp.AppProperties">
    <property name="build" value="@BUILD_NUMBER@"/>
</bean>

您可以设置要替换的Ant构建脚本 @BUILD_NUMBER@ 实际数字(参见 Copy

现在创建一个将包装的类 IAsset s并将内部版本号固定到URL上:

package myapp;

import java.io.InputStream;

import org.apache.hivemind.Location;
import org.apache.hivemind.Resource;
import org.apache.tapestry.IAsset;

public class BuildAwareAssetWrapper implements IAsset {
    private IAsset wrapped;
    private String build;

    public BuildAwareAssetWrapper(IAsset wrapped, String build) {
        this.wrapped = wrapped;
        this.build = build;
    }

    public String buildURL() {
        return addParam(wrapped.buildURL(), "build", build);
    }

    public InputStream getResourceAsStream() {
        return wrapped.getResourceAsStream();
    }

    public Resource getResourceLocation() {
        return wrapped.getResourceLocation();
    }

    public Location getLocation() {
        return wrapped.getLocation();
    }

    private static String addParam(String url, String name, String value) {
        if (url == null) url = "";
        char sep = url.contains("?") ? '&' : '?';
        return url + sep + name + '=' + value;
    }
}

AssetSourceImpl 类负责提供 IAsset findAsset() 方法,以便使用包装器类包装创建的资产:

package myapp;

import java.util.Locale;

import org.apache.hivemind.Location;
import org.apache.hivemind.Resource;
import org.apache.tapestry.IAsset;
import org.apache.tapestry.asset.AssetSourceImpl;

public class BuildAwareAssetSourceImpl extends AssetSourceImpl {
    private AppProperties props;

    @Override
    public IAsset findAsset(Resource base, String path, Locale locale, Location location) {
        IAsset asset = super.findAsset(base, path, locale, location);
        return new BuildAwareAssetWrapper(asset, props.getBuild());
    }

    public void setAppProperties(AppProperties props) {
        this.props = props;
    }
}

注意,该实现有一个setter,可以接受我们的Springbean。最后一步是使用Tapestry BuildAwareAssetSourceImpl 资产来源 . 我们通过覆盖中相应的服务点来实现这一点 hivemodule.xml :

<!-- Custom asset source -->
<implementation service-id="tapestry.asset.AssetSource">
    <invoke-factory service-id="hivemind.BuilderFactory" model="singleton">
        <construct class="myapp.BuildAwareAssetSourceImpl">
            <set-object property="appProperties" value="spring:appProperties"/>
            <set-configuration property="contributions" configuration-id="tapestry.asset.AssetFactories"/>
            <set-service property="lookupAssetFactory" service-id="tapestry.asset.LookupAssetFactory"/>
            <set-service property="defaultAssetFactory" service-id="tapestry.asset.DefaultAssetFactory"/>
        </construct>
    </invoke-factory>
</implementation>

就这样。如果运行应用程序并查看使用资产的任何页面的源代码,您将看到URL将具有新的 build 上面的参数。