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How to make client not disconnect when server response takes a long time

I have a Java backend with REST-API and an Angularjs frontend. Users can use the frontend to request information from the backend. When this happens, the backend generates a file on the fly and sends it to the frontend. So far so good.
The problem occurs when users request large amounts of information. This makes generating the file take so long that the frontend times out and aborts the connection.
Is there a way to reassure the client that a response is actually going to come, or increase the timeout limit for this one endpoint only? Alternatively, is there a way for the server to send two responses, one immediately after receiving the request and one after the file is generated?
The API endpoint looks like this:
#Path("download")
#Produces(MediaType.APPLICATION_OCTET_STREAM)
#Consumes(MediaType.APPLICATION_JSON)
public Response download() {
StreamingOutput stream = //stream containing file
return Response.ok(stream)
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"download.xlsx\"")
.build();
}
The frontend makes the request by doing window.open(download url, '_blank', '') (the content of the file depends on previous input from the user).

Spring Boot: efficiently get data from REST API

I have a Spring Boot application that (among other things) gets some data from a third party JSON API (secured with OAuth), processes the result and presents it to the user. The application receives approx. 1 request each second.
Unfortunately this process is very slow at the moment (and in many cases even ends with a 503 error) and I am looking for some idea to improve the implementation. (by the way: the third party API itself does not seem to be the bottleneck as a instance of my app running on my local machine using the exact same API response very fast at the same time that the deploy instance takes very long).
For the API call I use the Apache HTTP library - or more specifically the Async HTTP Client:
this.httpClientAsync = HttpAsyncClients.custom()
.setDefaultCredentialsProvider(credsProvider) //for forward proxy
.build();
And the actual call to the API is this:
updateToken(); //get or update OAuth Token
HttpGet httpget = new HttpGet(URL);
httpget.addHeader("Authorization", "Bearer " + accessToken);
Future<HttpResponse> f = this.httpClientAsync.execute(httpget, callback);
Do you have any suggestion on how to improve the implementation?
To be honest, I don't even have an idea where the bottleneck is at the moment. Any idea on how to find out about that?
Thanks for your hints!
One more thing/update:
the Spring Controller looks something like this:
#RequestMapping(value = "/api/v1/api_data")
public DeferredResult<ResponseEntity<Map>> getAPIData() throws IOException, InterruptedException {
DeferredResult<ResponseEntity<Map>> res = new DeferredResult<>();
triggerAPICall(new FutureCallback() {
public void completed(Object o) {
(...)
res.setResult(...);
}
(...)
}
return res;
}
Furthermore, I was originally not using the async version of the HTTP client, but the blocking version. This then even slowed down the rest of the application...

Accessing OneNote API from Java

I am interested in writing a Java application that can access my OneNote notebooks via the OneNote API. I am not sure how to gain access to that API from within Java. Can anybody point me to an example of how to get started here? I use Eclipse as my development environment.

This as straightforward process.
The 3 steps would be:
1) create a OneNote application on the OneNote developper's page. More info here https://dev.onedrive.com/app-registration.htm. This is a one time action.
2) your java application should then provide an authentification mechanism and a tolken-refresh mechanism.
See this post for more info on the authentification mechanism part : Getting a OneNote token with Java. This post is about the OAuth 2.0 flow 'Authorization code grant flow'. More info here https://msdn.microsoft.com/en-us/library/hh243647.aspx#flows
3) your java application calls adhoc API Rest methods to retreive the needed informations.
Example to retrieve all your notebooks (using OkHttp for Http requests):
private final static String NOTEBOOKS_ENDPOINT = "https://www.onenote.com/api/v1.0/me/notes/notebooks";
public Notebooks readAllNoteBooks() {
try {
if (client == null)
client = new OkHttpClient();
Request request = createOneNoteRequest(a_valid_tolken, NOTEBOOKS_ENDPOINT);
Response response = client.newCall(request).execute();
JsonObject content = UrlHelper.parseResponse(response);
System.out.println(content);
return Notebooks.build(content.get("value"));
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static Request createOneNoteRequest(String mAccessToken, String url) {
Request.Builder reqBuilder = new Request.Builder();
reqBuilder.url(url);
reqBuilder.header("Authorization", "Bearer " + mAccessToken);
return reqBuilder.build();
}
NoteBooks and NoteBook are 2 tiny classes matching the key attributes from the OneNote objects.

Microsoft has provided REST apis for accessing One note functionalities like creating and accessing notes. See OneNote Rest API reference.

singrass,
In addition to the above replies, the Android OneNote API sample may also help you. There is no OneNote application class that you can create (unless you want to create your own). You simply call the API through the HttpClient. If you are unfamiliar on how to call REST APIs in Java in general, this thread may help you.
-- James

How to build HTTP DELETE request with JSON encoded body using AsyncHttpClient

I need to write a HTTP client which to communicate with Floodlight OpenFlow controller via its REST API.
For testing I did it in python, and it worked OK. But now I'm in a situation where it has to be done in Java, of which I'm admittedly still at the beginner's level. One of my apps uses AsyncHttpClient to dispatch async GET requests, and works just fine. Now as a Floodlight's REST client, it has to do POST and DELETE with JSON encoded body. My code for an async POST request works very much as expected.
But no luck with DELETE.
Somehow it doesn't write JSON string into its request body.
The code is almost identical with POST. For debugging, I don't feed an AsyncCompletionHandler instance to execute() method.
System.out.println(ofEntry.toJson()); // this returns {"name": "xyz"} as expected.
Future<Response> f = httpClient.prepareRequest(new RequestBuilder("DELETE")
.setUrl("http://" + myControllerBaseUrl + urlPathFlowPostDelete)
.setHeader("content-type", "application/json")
.setBody(ofEntry.toJson())
.build()).execute();
System.out.println(f.getStatusCode()); // returns 200.
System.out.println(f.getResponseBody()); // returns {"status" : "Error! No data posted."}.
Just to make sure, I peeped into packet dump with wireshark, and found out the server isn't lying :)
The author of the library has written an extensive amount of relevant, valuable information, but unfortunately I can't find example code specifically for building a DELETE request.
I'd very much appreciate any suggestions, pointers, and of course pinpoint solutions!

Not sure that replying to my own question is appropriate here, but I have just found a related thread at the floodlight-dev Google group.
Problem with Static Flow Pusher DELETE REST method
So this could be a problem with Floodlight REST API which requires message body for a DELETE request to identify what to be deleted, whereas AHC is simply compliant with RFC2616.
I will follow the thread at Google group, and see how it will conclude among developers.

SOAP web service calls from Javascript

I'm struggling to successfully make a web service call to a SOAP web service from a web page. The web service is a Java web service that uses JAX-WS.
Here is the web method that I'm trying to call:
#WebMethod
public String sayHi(#WebParam(name="name") String name)
{
System.out.println("Hello "+name+"!");
return "Hello "+name+"!";
}
I've tried doing the web service call using the JQuery library jqSOAPClient (http://plugins.jquery.com/project/jqSOAPClient).
Here is the code that I've used:
var processResponse = function(respObj)
{
alert("Response received: "+respObj);
};
SOAPClient.Proxy = url;
var body = new SOAPObject("sayHi");
body.ns = ns;
body.appendChild(new SOAPObject("name").val("Bernhard"));
var sr = new SOAPRequest(ns+"sayHi",body);
SOAPClient.SendRequest(sr,processResponse);
No response seems to be coming back. When in jqSOAPClient.js I log the xData.responseXML data member I get 'undefined'. In the web service I see the warning
24 Mar 2011 10:49:51 AM com.sun.xml.ws.transport.http.server.WSHttpHandler handleExchange
WARNING: Cannot handle HTTP method: OPTIONS
I've also tried using a javascript library, soapclient.js (http://www.codeproject.com/kb/Ajax/JavaScriptSOAPClient.aspx). The client side code that I use here is
var processResponse = function(respObj)
{
alert("Response received: "+respObj);
};
var paramaters = new SOAPClientParameters();
paramaters.add("name","Bernhard");
SOAPClient.invoke(url,"sayHi",paramaters,true,processResponse);
I've bypassed the part in soapclient.js that fetches the WSDL, since it doesn't work
(I get an: IOException: An established connection was aborted by the software in your host machine on the web service side). The WSDL is only retrieved for the appropriate name space to use, so I've just replaced the variable ns with the actual name space.
I get exactly the same warning on the web service as before (cannot handle HTTP method: OPTIONS) and in the browser's error console I get the error "document is null". When I log the value of req.responseXML in soapclient.js I see that it is null.
Could anyone advise on what might be going wrong and what I should do to get this to work?

I found out what was going on here. It is the same scenario as in this thread: jQuery $.ajax(), $.post sending "OPTIONS" as REQUEST_METHOD in Firefox.
Basically I'm using Firefox and when one is doing a cross domain call (domain of the address of the web service is not the same as the domain of the web page) from Firefox using AJAX, Firefox first sends an OPTIONS HTTP-message (before it transmits the POST message), to determine from the web service if the call should be allowed or not. The web service must then respond to this OPTIONS message to tell if it allows the request to come through.
Now, the warning from JAX-WS ("Cannot handle HTTP method: OPTIONS") suggests that it won't handle any OPTIONS HTTP-messages. That's ok - the web service will eventually run on Glassfish.
The question now is how I can configure Glassfish to respond to the OPTIONS message.
In the thread referenced above Juha says that he uses the following code in Django:
def send_data(request):
if request.method == "OPTIONS":
response = HttpResponse()
response['Access-Control-Allow-Origin'] = '*'
response['Access-Control-Allow-Methods'] = 'POST, GET, OPTIONS'
response['Access-Control-Max-Age'] = 1000
response['Access-Control-Allow-Headers'] = '*'
return response
if request.method == "POST":
# ...
Access-Control-Allow-Origin gives a pattern which indicates which origins (recipient addresses) will be accepted (mine might be a bit more strict than simply allowing any origin) and Access-Control-Max-Age tells after how many seconds the client will have to request permission again.
How do I do this in Glassfish?

Have you actually tested that ws is working properly?
You can use SoapUI for inspecting request/response etc.
When you confirm that ws is working from SoapUI, inspect what is format of raw Soap message. Then try to inspect how it looks before sending with .js method, and compare them.
It might help you understand what is wrong.

Check if this helps
http://bugs.jquery.com/attachment/ticket/6029/jquery-disable-firefox3-cross-domain-magic.patch
it's marked as invalid
http://bugs.jquery.com/ticket/6029
but it might give you some hint
On the other hand, instead to override proper settings for cross-domain scripting might be better if you can create and call local page that will do request to ws and return result.
Or even better, you can create page that will receive url as param and do request to that url and just return result. That way it will be more generic and reusable.