OSGI Service CondperMadmin framework in the Java library (Guide to use the osgi Service CondPermadmin Framework in Java Class Libraries)
OSGI service CondPerMadmin framework in the Java class library
Introduction:
OSGI is a modular Java platform that provides a dynamic modular development framework.In OSGI, service is a mechanism that allows communication and interaction between modules.CondPerMadmin (Conditional Permission Admin) is an important component in the OSGI framework that allows developers to share different access control strategies between modules.This guide will introduce how to use the OSGI service CondPerMadmin framework in the Java library.
1. Configure OSGI environment and dependencies:
First, make sure that an OSGI framework (such as Apache Felix or Eclipse Equinox) is installed and configured.Add related OSGI dependencies to the project construction file, including API and implementation of CondPerMadmin.
2. Definition authority:
Before the Java library is used to define the required authority strategies before using the Conpermadmin framework.This can be implemented by using Java security strategy files and conditions permissions.
For example, create a Java security strategy file called "MyPermissions.Policy", and declare the permissions and conditional permissions required, as shown below::
grant {
permission java.io.FilePermission "/path/to/myFile.txt", "read";
condperm org.osgi.service.condpermadmin.BundleSignerCondition "myBundle", "mySignature";
}
In the above examples, the permissions of the read file "/path/to/myfile.txt" are first granted.Then, the conditional permissions descriptor of the CondPerMadmin specifically specifies a bundle package called "Mybundle" and signed "MySignature".
3. Registration permissions strategy:
Register the authority strategy in the code of the Java library so that the CondPerMadmin framework can be read and used.This can be implemented by using the CondPerMadmin's API method.
The following is a sample code fragment, which shows how to register permissions in the Java class library:
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.condpermadmin.ConditionalPermissionAdmin;
import org.osgi.service.condpermadmin.ConditionalPermissionUpdate;
import org.osgi.util.tracker.ServiceTracker;
public class PermissionPolicyRegistrar {
private final BundleContext bundleContext;
private ServiceTracker<ConditionalPermissionAdmin, ConditionalPermissionAdmin> tracker;
public PermissionPolicyRegistrar(BundleContext bundleContext) {
this.bundleContext = bundleContext;
}
public void registerPermissionPolicy() {
tracker = new ServiceTracker<>(bundleContext, ConditionalPermissionAdmin.class, null);
tracker.open();
ConditionalPermissionAdmin condPermAdmin = tracker.getService();
if (condPermAdmin != null) {
ConditionalPermissionUpdate update = condPermAdmin.newConditionalPermissionUpdate();
// Read permission for a file
update.getConditionalPermissionInfo().getAllow().add(new FilePermission("/path/to/myFile.txt", "read"));
// Bundle signing condition
Bundle bundle = bundleContext.getBundle();
update.getConditionalPermissionInfo().getAllow().add(
new BundleSignerCondition(bundle.getSymbolicName(), getBundleSignature(bundle)));
update.commit();
}
}
private String getBundleSignature(Bundle bundle) {
ServiceReference<PackageAdmin> ref = bundleContext.getServiceReference(PackageAdmin.class);
PackageAdmin packageAdmin = bundleContext.getService(ref);
BundleRevision revision = bundle.adapt(BundleRevision.class);
List<BundleCapability> caps = packageAdmin.getCapabilities(revision, BundleRevision.PACKAGE_NAMESPACE);
for (BundleCapability cap : caps) {
if ("osgi.wiring.package".equals(cap.getNamespace())) {
return cap.getAttributes().get(BundleRevision.BUNDLE_SYMBOLICNAME_ATTRIBUTE) + "/" +
cap.getAttributes().get(BundleRevision.BUNDLE_VERSION_ATTRIBUTE);
}
}
return null;
}
public void unregisterPermissionPolicy() {
if (tracker != null) {
tracker.close();
}
}
}
Please note that the above example code assumes that appropriate dependencies and imported packet sentences have been defined in the OSGI environment.
4. Limited use strategy:
Once the authority strategy is registered in the CondPerMadmin framework, other modules can use these strategies.By using CondPerMadmin's API, you can obtain current permissions, check whether there are specific permissions, and dynamically modify and adjust permissions as needed.
Below is a simple sample code fragment, which shows how to use registered permissions strategies in the Java class library:
import org.osgi.framework.BundleContext;
import org.osgi.service.condpermadmin.ConditionalPermissionAdmin;
import org.osgi.service.condpermadmin.ConditionalPermissionInfo;
import org.osgi.util.tracker.ServiceTracker;
public class PermissionPolicyConsumer {
private final BundleContext bundleContext;
private ServiceTracker<ConditionalPermissionAdmin, ConditionalPermissionAdmin> tracker;
public PermissionPolicyConsumer(BundleContext bundleContext) {
this.bundleContext = bundleContext;
}
public void checkPermissions() {
tracker = new ServiceTracker<>(bundleContext, ConditionalPermissionAdmin.class, null);
tracker.open();
ConditionalPermissionAdmin condPermAdmin = tracker.getService();
if (condPermAdmin != null) {
ConditionalPermissionInfo[] infos =
condPermAdmin.getConditionalPermissionInfos(bundleContext.getBundle());
// Check if the bundle has the permission to read the file
for (ConditionalPermissionInfo info : infos) {
if (info.getAllow().implies(new FilePermission("/path/to/myFile.txt", "read"))) {
// Perform actions that require permission
// ...
}
}
}
}
public void stop() {
if (tracker != null) {
tracker.close();
}
}
}
The above example code demonstrates how to check whether the current module has the permissions of reading files.
in conclusion:
This guide provides guidelines for using the OSGI service CondPerMadmin framework in the Java library.By defining and registered authority strategies, and APIs using CondPerMadmin, you can share and control different access control strategies between modules.This provides developers with greater flexibility and security to achieve modular Java application development.
