OSGI service CondPerMadmin framework technical analysis
OSGI service CondPerMadmin framework technical analysis
OSGI is a modular Java platform that is used to build scalable, dynamic and reusable applications.In complex applications, the authority between different modules is needed to manage and control the permissions.OSGI provides the CondPerMadmin framework that is used to realize the authority management of OSGI services.
The CondPerMadmin framework achieves the permissions control of OSGI services by defining and evaluating conditions.In this framework, each installed Bundle is assigned a set of conditions, which describes the operating environment and access permissions of Bundle.These conditions can be defined based on Bundle's attributes, packages, services, and other bundled conditions.
In the CondPerMadmin framework, the permissions are defined by resources and permissions.Resources can be bundle, bags or services, while the type of permissions describes the operation of these resources.For example, access resources, modify resources or execute resources.
The main technical principles of the CONDPERMADMIN framework are as follows:
1. Condition definition: The CondPerMadmin framework allows developers to define conditions and associate it with Bundle.Conditions can be static. For example, the attributes or version number of Bundle can also be dynamic, such as Bundle's service dependencies.By combination and matching these conditions, the permissions of Bundle can be flexibly defined and configured.
2. permissions calculation: By analyzing and evaluating conditions, the CondPerMadmin framework can determine the permissions required for each Bundle.According to the degree of matching and permissions of the conditions, the system will allocate corresponding permissions for Bundle.In this way, each Bundle can only access its authorized resources while preventing access to unauthorized resources.
3. Execution permissions: The CondPerMadmin framework is responsible for performing inspection of Bundle permissions during runtime.Before accessing resources or executing operations, CorMadmin will check the permissions of the current Bundle and compare with the required permissions.Only when Bundle has the right authority, can access resources or execute operations.
Below is a Java code example using the CondPerMadmin framework:
import org.osgi.service.condpermadmin.BundleLocationCondition;
import org.osgi.service.condpermadmin.ConditionalPermissionAdmin;
import org.osgi.service.condpermadmin.ConditionInfo;
import org.osgi.service.condpermadmin.ConditionalPermissionAdminListener;
public class ExampleCondPermAdmin {
private ConditionalPermissionAdmin condPermAdmin;
public ExampleCondPermAdmin(ConditionalPermissionAdmin condPermAdmin) {
this.condPermAdmin = condPermAdmin;
}
public void registerPermission(Bundle bundle, String resource, String action) {
BundleLocationCondition cond = new BundleLocationCondition(bundle.getLocation());
ConditionInfo[] conditions = new ConditionInfo[] { new ConditionInfo(BundleLocationCondition.class.getName(), cond.getCondition(), null) };
this.condPermAdmin.newConditionalPermissionUpdate().getConditionalPermissionInfos()[0]
.addPermissions(new PermissionInfo[] { new PermissionInfo(resource, action) })
.setAccessDecision(ConditionalPermissionInfo.ALLOW)
.setConditionInfos(conditions)
.commit();
}
public boolean hasPermission(Bundle bundle, String resource, String action) {
BundleLocationCondition cond = new BundleLocationCondition(bundle.getLocation());
ConditionInfo[] conditions = new ConditionInfo[] { new ConditionInfo(BundleLocationCondition.class.getName(), cond.getCondition(), null) };
return this.condPermAdmin.getConditionalPermissionInfos()[0]
.hasPermission(new PermissionInfo(resource, action), conditions);
}
}
In the above example, we created a class called `ExampleCondPermadmin`, which uses the Conpermadmin framework to manage permissions.The `registerPerMission 'method is used to register the permissions required for a bundle. This method uses the position of Bundle as a condition and is registered with resources and operations.`Haspermission 'method is used to check whether the given Bundle has the permissions to access specific resources and operations.
Summarize:
By using the OSGI service CondPerMadmin framework, we can effectively manage and control the permissions between modules in complex applications.The CondPerMadmin framework provides a flexible and dynamic authority management mechanism through conditional definition and permissions calculation.Developers can define conditions according to their own needs and allocate corresponding permissions for each Bundle to ensure the security access and operation of resources.
