6.Authorizer（授权、访问控制）

Authorizer主要是执行授权操作,即访问资源的控制。在shiro里，authorizer通常不直接使用，而是配置在SecurityManager里，由SecurityManager委托调用。
AuthorizingRealm和ModularRealmAuthorizer
前面讲过一个AuthorizingRealm，它也实现了Authorizer的接口。
AuthorizingRealm：
1.负责和底层的数据库交互，获取所需授权数据
2.缓存授权数据
3.真正授权逻辑判断
ModularRealmAuthorizer：
1.里面设置了realms，真正的授权逻辑交互是通过迭代realms，调用realm的授权功能
2.和SecurityManager协调授权访问，实现PAM

1.Authorizer

public interface Authorizer {

    //判断PrincipalCollection是否有String permission(该String会转换为Permission对象)资源权限。是：true 否：false
    boolean isPermitted(PrincipalCollection principals, String permission);

    //判断PrincipalCollection是否有permission资源权限。是：true 否：false
    boolean isPermitted(PrincipalCollection subjectPrincipal, Permission permission);

    //返回一组String permissions授权判断的 boolean[]
    boolean[] isPermitted(PrincipalCollection subjectPrincipal, String... permissions);

    //返回一组permissions授权判断的 boolean[]
    boolean[] isPermitted(PrincipalCollection subjectPrincipal, List<Permission> permissions);

    //判断一组String permissions是否 全部 授权成功。 是：true 否：false
    boolean isPermittedAll(PrincipalCollection subjectPrincipal, String... permissions);

    //判断一组permissions是否 全部 授权成功。 是：true 否：false
    boolean isPermittedAll(PrincipalCollection subjectPrincipal, Collection<Permission> permissions);

    //判断PrincipalCollection是否有String permission(该String会转换为Permission对象)资源权限。 失败：抛出AuthorizationException异常
    void checkPermission(PrincipalCollection subjectPrincipal, String permission) throws AuthorizationException;

    //判断PrincipalCollection是否有permission资源权限。 失败：抛出AuthorizationException异常
    void checkPermission(PrincipalCollection subjectPrincipal, Permission permission) throws AuthorizationException;

    //判断一组String permissions是否 全部 授权成功。 失败：抛出AuthorizationException异常
    void checkPermissions(PrincipalCollection subjectPrincipal, String... permissions) throws AuthorizationException;

    //判断一组permissions是否 全部 授权成功。 失败：抛出AuthorizationException异常
    void checkPermissions(PrincipalCollection subjectPrincipal, Collection<Permission> permissions) throws AuthorizationException;

    //根据subjectPrincipal判断是否存在该角色。 是：true 否：false
    boolean hasRole(PrincipalCollection subjectPrincipal, String roleIdentifier);

    //根据subjectPrincipal判断一组role是否授权成功，然后返回boolean[]
    boolean[] hasRoles(PrincipalCollection subjectPrincipal, List<String> roleIdentifiers);

    //判断是否一组role全部授权成功。 是：true 否：false
    boolean hasAllRoles(PrincipalCollection subjectPrincipal, Collection<String> roleIdentifiers);

    //根据subjectPrincipal判断是否存在该角色。 失败：抛出AuthorizationException异常
    void checkRole(PrincipalCollection subjectPrincipal, String roleIdentifier) throws AuthorizationException;

    //判断是否一组（集合）role全部授权成功。 失败：抛出AuthorizationException异常
    void checkRoles(PrincipalCollection subjectPrincipal, Collection<String> roleIdentifiers) throws AuthorizationException;

    //判断是否一组（数组）role全部授权成功。 失败：抛出AuthorizationException异常
    void checkRoles(PrincipalCollection subjectPrincipal, String... roleIdentifiers) throws AuthorizationException;

}

2.ModularRealmAuthorizer

/** ModularRealmAuthorizer： 1.里面设置了realms，真正的授权逻辑交互是通过迭代realms，调用realm的授权功能 2.和SecurityManager协调授权访问，实现PAM **/
public class ModularRealmAuthorizer implements Authorizer, PermissionResolverAware, RolePermissionResolverAware {

    //Realm集合，真正的授权处理
    protected Collection<Realm> realms;

    //Permission转换器，String->Permission
    protected PermissionResolver permissionResolver;

    //角色资源转换器，转换角色为一组确切的资源
    protected RolePermissionResolver rolePermissionResolver;


    public ModularRealmAuthorizer() {
    }


    public ModularRealmAuthorizer(Collection<Realm> realms) {
        setRealms(realms);
    }


    public Collection<Realm> getRealms() {
        return this.realms;
    }


    public void setRealms(Collection<Realm> realms) {
        this.realms = realms;
    //Realm设置之后调用applyPermissionResolverToRealms设置this.PermissionResolver到Realm里的PermissionResolver
        applyPermissionResolverToRealms();
    //Realm设置之后调用applyRolePermissionResolverToRealms设置this.PermissionResolver到Realm里的RolePermissionResolver
        applyRolePermissionResolverToRealms();

    /** 上面两个方法的寓意主要是，如果多个Realm被同时设置进来，保证他们的资源转换器是一致的，该ModularRealmAuthorizer 作为SecurityManager委托的对象，且代理了真正的Realm执行授权逻辑，也可以看做是Realm的门面。 **/
    }


    public PermissionResolver getPermissionResolver() {
        return this.permissionResolver;
    }


    public void setPermissionResolver(PermissionResolver permissionResolver) {
        this.permissionResolver = permissionResolver;
    //调用applyPermissionResolverToRealms设置this.PermissionResolver到Realm里的PermissionResolver
        applyPermissionResolverToRealms();
    }

    //迭代Realm设置this.PermissionResolver到Realm的PermissionResolver
    protected void applyPermissionResolverToRealms() {
        PermissionResolver resolver = getPermissionResolver();
        Collection<Realm> realms = getRealms();
        if (resolver != null && realms != null && !realms.isEmpty()) {
            for (Realm realm : realms) {
                if (realm instanceof PermissionResolverAware) {
                    ((PermissionResolverAware) realm).setPermissionResolver(resolver);
                }
            }
        }
    }


    public RolePermissionResolver getRolePermissionResolver() {
        return this.rolePermissionResolver;
    }


    public void setRolePermissionResolver(RolePermissionResolver rolePermissionResolver) {
        this.rolePermissionResolver = rolePermissionResolver;
    //调用applyRolePermissionResolverToRealms设置this.PermissionResolver到Realm里的RolePermissionResolver
        applyRolePermissionResolverToRealms();
    }


    //迭代Realm设置this.RolePermissionResolver到Realm的RolePermissionResolver
    protected void applyRolePermissionResolverToRealms() {
        RolePermissionResolver resolver = getRolePermissionResolver();
        Collection<Realm> realms = getRealms();
        if (resolver != null && realms != null && !realms.isEmpty()) {
            for (Realm realm : realms) {
                if (realm instanceof RolePermissionResolverAware) {
                    ((RolePermissionResolverAware) realm).setRolePermissionResolver(resolver);
                }
            }
        }
    }


    //保证Realm不为空，如果为空抛出异常
    protected void assertRealmsConfigured() throws IllegalStateException {
        Collection<Realm> realms = getRealms();
        if (realms == null || realms.isEmpty()) {
            String msg = "Configuration error: No realms have been configured! One or more realms must be " +
                    "present to execute an authorization operation.";
            throw new IllegalStateException(msg);
        }
    }

    //迭代Realm ，调用realm.isPermitted(principals, String permission)，有一个成功则返回true
    public boolean isPermitted(PrincipalCollection principals, String permission) {
        assertRealmsConfigured();
        for (Realm realm : getRealms()) {
            if (!(realm instanceof Authorizer)) continue;
            if (((Authorizer) realm).isPermitted(principals, permission)) {
                return true;
            }
        }
        return false;
    }

    //迭代Realm ，调用realm.isPermitted(principals, Permission permission)，有一个成功则返回true
    public boolean isPermitted(PrincipalCollection principals, Permission permission) {
        assertRealmsConfigured();
        for (Realm realm : getRealms()) {
            if (!(realm instanceof Authorizer)) continue;
            if (((Authorizer) realm).isPermitted(principals, permission)) {
                return true;
            }
        }
        return false;
    }

    //迭代permissions，调用this.isPermitted(PrincipalCollection principals, String permission)，返回一组boolean[]
    public boolean[] isPermitted(PrincipalCollection principals, String... permissions) {
        assertRealmsConfigured();
        if (permissions != null && permissions.length > 0) {
            boolean[] isPermitted = new boolean[permissions.length];
            for (int i = 0; i < permissions.length; i++) {
                isPermitted[i] = isPermitted(principals, permissions[i]);
            }
            return isPermitted;
        }
        return new boolean[0];
    }

    //迭代permissions，调用this.isPermitted(PrincipalCollection principals, Permission permission)，返回一组boolean[]
    public boolean[] isPermitted(PrincipalCollection principals, List<Permission> permissions) {
        assertRealmsConfigured();
        if (permissions != null && !permissions.isEmpty()) {
            boolean[] isPermitted = new boolean[permissions.size()];
            int i = 0;
            for (Permission p : permissions) {
                isPermitted[i++] = isPermitted(principals, p);
            }
            return isPermitted;
        }

        return new boolean[0];
    }

    //迭代permissions，调用this.isPermitted(PrincipalCollection principals, String permission)有一个false，则false。否则true
    public boolean isPermittedAll(PrincipalCollection principals, String... permissions) {
        assertRealmsConfigured();
        if (permissions != null && permissions.length > 0) {
            for (String perm : permissions) {
                if (!isPermitted(principals, perm)) {
                    return false;
                }
            }
        }
        return true;
    }

    //迭代permissions，调用this.isPermitted(PrincipalCollection principals, Permission permission)有一个false，则false。否则true
    public boolean isPermittedAll(PrincipalCollection principals, Collection<Permission> permissions) {
        assertRealmsConfigured();
        if (permissions != null && !permissions.isEmpty()) {
            for (Permission permission : permissions) {
                if (!isPermitted(principals, permission)) {
                    return false;
                }
            }
        }
        return true;
    }

    //调用this.isPermitted(PrincipalCollection principals, String permission),返回false则抛出异常：UnauthorizedException(
    public void checkPermission(PrincipalCollection principals, String permission) throws AuthorizationException {
        assertRealmsConfigured();
        if (!isPermitted(principals, permission)) {
            throw new UnauthorizedException("Subject does not have permission [" + permission + "]");
        }
    }

    //调用this.isPermitted(PrincipalCollection principals, Permission permission),返回false则抛出异常：UnauthorizedException(
    public void checkPermission(PrincipalCollection principals, Permission permission) throws AuthorizationException {
        assertRealmsConfigured();
        if (!isPermitted(principals, permission)) {
            throw new UnauthorizedException("Subject does not have permission [" + permission + "]");
        }
    }

    //迭代permissions。调用this.checkPermission(PrincipalCollection principals, String permission)
    public void checkPermissions(PrincipalCollection principals, String... permissions) throws AuthorizationException {
        assertRealmsConfigured();
        if (permissions != null && permissions.length > 0) {
            for (String perm : permissions) {
                checkPermission(principals, perm);
            }
        }
    }

    //迭代permissions。调用this.checkPermission(PrincipalCollection principals, Permission permission)
    public void checkPermissions(PrincipalCollection principals, Collection<Permission> permissions) throws AuthorizationException {
        assertRealmsConfigured();
        if (permissions != null) {
            for (Permission permission : permissions) {
                checkPermission(principals, permission);
            }
        }
    }

    //迭代Realms。如果有一个成功则返回true，否则：false
    public boolean hasRole(PrincipalCollection principals, String roleIdentifier) {
        assertRealmsConfigured();
        for (Realm realm : getRealms()) {
            if (!(realm instanceof Authorizer)) continue;
            if (((Authorizer) realm).hasRole(principals, roleIdentifier)) {
                return true;
            }
        }
        return false;
    }

    //迭代roleIdentifiers,调用this.hasRole(PrincipalCollection principals, String roleIdentifier),封装结果到Boolean[]返回
    public boolean[] hasRoles(PrincipalCollection principals, List<String> roleIdentifiers) {
        assertRealmsConfigured();
        if (roleIdentifiers != null && !roleIdentifiers.isEmpty()) {
            boolean[] hasRoles = new boolean[roleIdentifiers.size()];
            int i = 0;
            for (String roleId : roleIdentifiers) {
                hasRoles[i++] = hasRole(principals, roleId);
            }
            return hasRoles;
        }

        return new boolean[0];
    }

    //迭代roleIdentifiers,所有成功则返回true,否则false
    public boolean hasAllRoles(PrincipalCollection principals, Collection<String> roleIdentifiers) {
        assertRealmsConfigured();
        for (String roleIdentifier : roleIdentifiers) {
            if (!hasRole(principals, roleIdentifier)) {
                return false;
            }
        }
        return true;
    }

    //判断是否有角色role，没有则抛出异常UnauthorizedException
    public void checkRole(PrincipalCollection principals, String role) throws AuthorizationException {
        assertRealmsConfigured();
        if (!hasRole(principals, role)) {
            throw new UnauthorizedException("Subject does not have role [" + role + "]");
        }
    }

    //判断一组（集合）roles，是否全部存在，不是则抛出异常
    public void checkRoles(PrincipalCollection principals, Collection<String> roles) throws AuthorizationException {
        //SHIRO-234 - roles.toArray() -> roles.toArray(new String[roles.size()])
        if (roles != null && !roles.isEmpty()) checkRoles(principals, roles.toArray(new String[roles.size()]));
    }

    //判断一组（数组）roles，是否全部存在，不是则抛出异常
    public void checkRoles(PrincipalCollection principals, String... roles) throws AuthorizationException {
        assertRealmsConfigured();
        if (roles != null) {
            for (String role : roles) {
                checkRole(principals, role);
            }
        }
    }
}