Restlet实战（九）访问敏感资源之Digest认证

首先对所有的请求进行安全检验和认证，后面会给出对固定的URL进行安全认证的情况。对Restlet1.1.5来说，需要借助于Guard类来完成。

 

说一下大概的思路，建立一个Guard，并把它直接attach到Componet，当请求过来以后，会首先路由到这个Guard，如果通过认证，则路由到对应URL的Resource，否则，拦截掉。

 

首先修改Spring的配置文件：

 

	<bean id="component" class="org.restlet.ext.spring.SpringComponent">
		<property name="defaultTarget" ref="guard" />
	</bean>
	
	<bean id="guard" class="com.mycompany.restlet.filter.CustomerGuardFilter"> 
		<property name="next" ref="restRoute"/>
		<property name="secretResolver" ref="customerResolver"/> 
	</bean>
	
	<bean id="customerResolver" class="com.mycompany.restlet.filter.CustomerResolver"/>
	

 

从上述配置文件能看到，我们为SpringComponent的defaultTarget属性配置了一个Guard，当然这个是我们自己customized的一个Guard。而对于这个Guard，则指定其中的两个属性：next和secretResolver，next的意思是，如果通过校验和认证，则路由到下一个restlet实例，而secretResolver则是进行校验的地方。相关代码如下：

 

 

public class CustomerGuardFilter extends Guard {

	public CustomerGuardFilter(Context context, ChallengeScheme scheme, String realm) {
		super(context, scheme, realm);
	}
	
	public CustomerGuardFilter(){
		this(Context.getCurrent(), ChallengeScheme.HTTP_DIGEST, "realm");
	}
	
}

 

public class CustomerResolver extends Resolver<char[]> {

    /**
     * Returns the value that corresponds to the given name.
     */
    @Override
    public char[] resolve(String name) {
        // Could have a look into a database, LDAP directory, etc.
        if ("login".equals(name)) {
            return "secret".toCharArray();
        }

        return null;
    }

}

 

CustomerResolver类里面注释的地方，实际上就是我们在产品环境中从数据库或者LDAPdirectory或者别的地方取出密码的过程，这里，仅仅是为了测试，所以，直接硬编码了。

 

下面我们分别分别使用Restlet和Httpclient提供的API来编写客户端进行测试：

 

1.使用Restlet来测试

 

public static void testClientWithRestlet() {
	Reference reference = new Reference("http://localhost:8080/restlet/resources/customers");
	Client client = new Client(Protocol.HTTP);
	Request request = new Request(Method.GET, reference);

	ChallengeResponse challengeResponse = new ChallengeResponse(ChallengeScheme.HTTP_DIGEST, "login", "secret");
	request.setChallengeResponse(challengeResponse);

	// Send the first request
	Response response = client.handle(request);

	// Complete the challengeResponse object according to the server's data
	Form form = new Form();
	form.add("username", "login");
	form.add("uri", reference.getPath());

	// Loop over the challengeRequest objects sent by the server.
	for (ChallengeRequest challengeRequest : response.getChallengeRequests()) {
		// Get the data from the server's response.
		if (ChallengeScheme.HTTP_DIGEST.equals(challengeRequest.getScheme())) {
			Series<Parameter> params = challengeRequest.getParameters();
			form.add(params.getFirst("nonce"));
			form.add(params.getFirst("realm"));
			form.add(params.getFirst("domain"));
			form.add(params.getFirst("algorithm"));
			form.add(params.getFirst("qop"));
		}
	}

	// Compute the required data
	String a1 = Engine.getInstance().toMd5("login" + ":" + form.getFirstValue("realm") + ":" + "secret");
	String a2 = Engine.getInstance().toMd5(request.getMethod() + ":" + form.getFirstValue("uri"));
	form.add("response", Engine.getInstance().toMd5(a1 + ":" + form.getFirstValue("nonce") + ":" + a2));
	challengeResponse.setCredentialComponents(form);

	// Send the completed request
	request.setChallengeResponse(challengeResponse);
	response = client.handle(request);
}

 

 2. 使用Httpclient测试

 

public static void testClientWithHttpclient() throws Exception{
	HttpClient client = new HttpClient();
	client.getState().setCredentials(
		new AuthScope("localhost", 8080, "realm"),
		new UsernamePasswordCredentials("login", "secret"));

	List<String> authPrefs = new ArrayList<String>();
	authPrefs.add(AuthPolicy.DIGEST);
	client.getParams().setParameter(AuthPolicy.AUTH_SCHEME_PRIORITY, authPrefs);

	GetMethod httpget = new GetMethod("http://localhost:8080/restlet/resources/customers");

	try {
		int status = client.executeMethod(httpget);
		// print the status and response
		System.out.println(status);
		System.out.println(httpget.getStatusLine());
		System.out.println(httpget.getResponseBodyAsString());
	} finally {
		// release any connection resources used by the method
		httpget.releaseConnection();
	}            
}