I am trying to make http request to server from my GWT Application
Below is the code i am using which works fine from Client Side ..
But I want to do this from Server side ..
If I can get some solution for that
String url = "http://www.myserver.com/getData?type=3";
RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL.encode(url));
try {
Request request = builder.sendRequest(null, new RequestCallback() {
public void onError(Request request, Throwable exception) {
// Couldn't connect to server (could be timeout, SOP violation, etc.)
}
public void onResponseReceived(Request request, Response response) {
if (200 == response.getStatusCode()) {
// Process the response in response.getText()
} else {
// Handle the error. Can get the status text from response.getStatusText()
}
}
});
} catch (RequestException e) {
// Couldn't connect to server
}
Reference: www.gwtproject.org/doc/latest/DevGuideServerCommunication.html
com.google.gwt.http.client.RequestBuilder is meant to be used on the GWT client side.
For your server side code to make HTTP requests, I recommend using the Apache HttpClient library.
Related
There is a good example for sharing HttpSession between Websocket and Rest service. (Spring DispatchServlet cannot find resource within Jetty) But it doesn't work for me. I'm not sure is there any thing I'm missing?
I'm using Jetty as websocket server and also I created a WebApp as well which injected by SpringConfig.
private void init() throws Exception
{
Server server = new Server();
// Create SSL Connector
ServerConnector serverConnector = getSSLConnector(server);
// Bundle to server
server.setConnectors(new Connector[] { serverConnector });
// Create request handler collection
HandlerCollection handlers = new HandlerCollection();
// Add WebSocket handler
final ServletContextHandler servletContextHandler = getWebSocketContextHandler();
handlers.addHandler(servletContextHandler);
// Add Servlet handler
handlers.addHandler(getWebAppServletContextHandler());
server.setHandler(handlers);
// Initial WebSocket
WebSocketServerContainerInitializer.configureContext(servletContextHandler);
// Start Jetty
server.start();
server.join();
}
Both WebSocket and Rest are working under same port perfectly, of course, with different context paths.
Now, I created a Rest service:
#RequestMapping(value = "/login", method = RequestMethod.POST)
#Consumes({ MediaType.APPLICATION_JSON_VALUE })
#Produces({ MediaType.APPLICATION_JSON_VALUE })
public #ResponseBody Message login(#RequestBody Credential credential, #Context HttpServletRequest servlerRequest)
{
...
HttpSession session = servlerRequest.getSession(true);
session.setAttribute("userName", credential.getUserName());
...
Message message = new Message();
...
return message;
}
In this service I created a HttpSession and stored something in. As I said, it works, and so does the session.
Rest client:
public void login() throws KeyManagementException, NoSuchAlgorithmException
{
final String loginServiceUri = HTTP_SERVICE_BASE_URI + "/login";
ClientConfig clientConfig = new DefaultClientConfig();
...
Client client = Client.create(clientConfig);
WebResource webResource = client.resource(loginServiceUri);
ClientResponse response = webResource
.type("application/json")
.post(ClientResponse.class, new Credential("user","pass"));
if (response.getStatus() != 200) {
throw new RuntimeException("Failed : HTTP error code : " + response.getStatus());
}
List<NewCookie>cookies = response.getCookies();
ClientEndpointConfigurator.setCookies(cookies); <== Store cookies as well as session to ClientEndpointConfigrator class
Message message = response.getEntity(Message.class);
...
}
ClientEndpointConfigrator class has a static list for all cookies which like this:
public class ClientEndpointConfigurator extends ClientEndpointConfig.Configurator {
private static List<NewCookie> cookies = null;
public static void setCookies(List<NewCookie> cookies) {
ClientEndpointConfigurator.cookies = cookies;
}
...
#Override
public void beforeRequest(Map<String, List<String>> headers) {
...
if(null != cookies)
{
List<String> cookieList = new ArrayList<String>();
for(NewCookie cookie: cookies)
{
cookieList.add(cookie.toString());
}
headers.put("Cookie", cookieList);
}
...
}
}
beforeRequest() method will put all cookies to request header. If you inspect the cookieList, you will see:
[JSESSIONID=tvum36z6j2bc1p9uf2gumxguh;Version=1;Path=/rs;Secure]
Things looks prefect.
Finally, create a server end ServerEndpointConfigurator class, and override the modifyHandshake() method to retrieve the session and cookies
public class SpringServerEndpointConfigurator extends ServerEndpointConfig.Configurator {
#Override
public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response) {
super.modifyHandshake(sec, request, response);
httpSession = (HttpSession)request.getHttpSession(); <== **It returns null here!**
...
}
}
}
I can't get my HttpSession back! and if you print headers out, you will see the cookie has been changed:
Cookie: JSESSIONID="tvum36z6j2bc1p9uf2gumxguh";$Path="/rs"
Any one knows what's the reason?
All right, I figured it out, it's because I put WebSocket and Rest to different context handler. Jetty keeps handlers isolate to each other. To share session information, you have to put them together.
But if someone does want to separate them, it is still possible done by sharing SessionManager or SessionHandler. There are many ways to achieve this, you can inject SessionHandler to each ServletContext or just define it as a static variable and put it on somewhere every one can reach, each way works.
I have created a very simple servlet that uses HTTP Post method. I have tested it on my local Apache Tomcat server using a simple HTML form that works. I want to integrate it with my GWT app. I am able to call it using FormPanel - in that case it downloads content and there is a flicker in my browser window.
I know I need to use RequestBuilder to access it. But my response.getStatusCode() in my overloaded public void onResponseReceived(Request request, Response response) method always return status as 0 and response.getText() return null
String url = "http://localhost:8080/servlets/servlet/ShapeColor";
builder = new RequestBuilder(RequestBuilder.POST, URL.encode(url));
try {
String json = getJSONString();
//builder.setTimeoutMillis(10000);
builder.setHeader("Access-Control-Allow-Origin", "*");
builder.setHeader("Content-type", "application/x-www-form-urlencoded");
builder.sendRequest(json, new RequestCallback() {
#Override
public void onError(Request request, Throwable exception) {
Window.alert("Couldn't retrieve JSON");
}
#Override
public void onResponseReceived(Request request, Response response) {
if (200 == response.getStatusCode()) {
System.out.println("res:"+response.getText());
} else {
System.out.println("err: " + response.getStatusCode()+","+response.getText());
}
}
});
//Request response = builder.send();
} catch (RequestException e) {
// TODO Auto-generated catch block
}
I have tried many thing including changing my servlet following CORS reference ( https://code.google.com/p/gwtquery/wiki/Ajax#CORS_%28Cross_Origin_Resource_Sharing%29 )
It always works on browser using my test.html, but not from my App. Although, onResponseReceived method always gets called
Thanks
KKM
Have you checked if your call in the app violates the Same-origin policy (http://en.wikipedia.org/wiki/Same-origin_policy) in some way? The GWT RequestBuilder uses XMLHttpRequest internally, so it does fall under the SOP.
Does your GWT app run inside the same domain (server + port) as the servlet? Does it use the same protocol (https or http)?
i'have two web appli, tapestry appli and a simple web appli(servelt). in tapestry appli , i have a form, and when it'll be sent, i call a httpClient for sending some informations to author appli using apache's httpClient. like this
void onSubmitFromForm() {
try {
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://localhost:8080/appli2/recep");
post.setHeader("referer", "http://localhost:9090/app1/start");
List<NameValuePair> param = new ArrayList<NameValuePair>();
param.add(new BasicNameValuePair("_data", getData());
post.setEntity(new UrlEncodedFormEntity(param));
HttpResponse response = client.execute(post);
response ?????
} catch (Exception e) {
e.printStackTrace();
}
}
And in my servelt recep of the simple web appli(2) i do the same like below
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
try {
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(request.getHeader("referer"));
post.setHeader("p",getP());
client.execute(post);
} catch (Exception e) {
e.printStackTrace();
}
}
So, my recep reviev data from my form but it'cannot response it, i'would that tapersty appli could recieve the param 'P' from the simple web appli ?
thanks
If I'm correct you want your tapestry application to POST some form data received from a form submit within Tapestry to a servlet running on another application.
If this is what you want then what is missing is the haneling of the request and constructing a response in your servlet. Because both your tapestry page and your servlet are POST'ing meaning neither constructs a response for your HttpClient to deal with.
In your servlet you could:
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException
{
response.setContentType("text/plain");
PrintWriter out = response.getWriter();
out.println(getP());
out.close();
}
And deal with the response in your tapesty form handler.
I am testing HttpClient 4.2 by hitting a mixture of http and https links.
HttpClient seems to stick with the protocol from the first call. If the first call is http, then all following https calls fail but http calls are fine. And vice versa.
Here is the test code I used.
#Test
public void testNoRedirectMixed() throws ClientProtocolException, IOException {
HttpClient httpclient = new DefaultHttpClient();
httpclient=WebClientDevWrapper.wrapClient(httpclient);
HttpClientParams.setRedirecting(httpclient.getParams(), false);
{
HttpGet httpget = new HttpGet("http://www.hotmail.com");
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
assertTrue(EntityUtils.toString(entity).indexOf("com")>0);
}
try {
HttpGet httpget = new HttpGet("https://www.hotmail.com");
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
}catch (Exception e) {
e.printStackTrace();
}
{
HttpGet httpget = new HttpGet("http://www.baidu.com");
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
assertTrue(EntityUtils.toString(entity).indexOf("com")>0);
}
}
The second request (https) will fail, but the baidu request is fine.
Caused by: org.apache.http.HttpException: Unable to establish route: planned = {s}->https://www.hotmail.com; current = {s}->http://www.hotmail.com
at org.apache.http.impl.client.DefaultRequestDirector.establishRoute(DefaultRequestDirector.java:842)
I also have to disable redirection because hotmail redirects request: http://www.hotmail.com -> https://www.hotmail.com or https://www.hotmail.com -> https://www.live.com. A similar error is thrown in either cases.
The wrapper is shown below. It is used to accept all certificates.
public class WebClientDevWrapper {
public static HttpClient wrapClient(HttpClient base) {
try {
SSLContext ctx = SSLContext.getInstance("TLS");
X509TrustManager tm = new X509TrustManager() {
public void checkClientTrusted(X509Certificate[] xcs,
String string) throws CertificateException {
}
public void checkServerTrusted(X509Certificate[] xcs,
String string) throws CertificateException {
}
public X509Certificate[] getAcceptedIssuers() {
return new X509Certificate[]{};
}
};
ctx.init(null, new TrustManager[] { tm }, null);
SSLSocketFactory ssf = new SSLSocketFactory(ctx);
ssf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);
ClientConnectionManager ccm = base.getConnectionManager();
SchemeRegistry sr = ccm.getSchemeRegistry();
sr.register(new Scheme("https", ssf, 443));
DefaultHttpClient client= new DefaultHttpClient(ccm, base.getParams());
return client;
} catch (Exception ex) {
ex.printStackTrace();
return null;
}
}
}
HttpClient should be able to manage connections absolutely transparently to the user. This problem is likely to be caused by a regression introduced in the 4.2 release (see HTTPCLIENT-1193).
Use either PoolingConnectionManager or SingleConnectionManager instead of the default one until 4.2.1 version is released.
You are trying to use one connection to communicate to a number of different sites. AFAIR You have to create new connection (== new client) for every unique site.
I have a GWT + Spring Security web app. I was trying to add:
<security:session-management invalid-session-url="/X.html"/>
However, when I try to test this. It seems I see a:
com.google.gwt.user.client.rpc.InvocationException
with message as the HTML content of X.html. Can someone please advise on how to fix this?
Because GWT communicates with a server via Ajax RPC requests, the browser will not be redirected to X.html. What you need to do in your service calls is throw an exception if they are not authorized and handle in in void onFailure(Throwable caught) method of your AsyncCallback.
If you want to redirect to /X.html try:
Window.Location.replace(GWT.getHostPageBaseURL()+"X.html");
However, if you want to send the request to the server use RequestBuilder:
String url = GWT.getHostPageBaseURL() + "/X.html";
RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL.encode(url));
try {
Request request = builder.sendRequest(null, new RequestCallback() {
public void onError(Request request, Throwable exception) {
// invalid request
}
public void onResponseReceived(Request request, Response response) {
if (200 == response.getStatusCode()) {
// success
} else {
// sth went wrong
}
}
});
} catch (RequestException e) {
// couldn't connect to server
}