Reccently, I am working on a project in Windows Phone. and In this project, to validate a user, I need to check at 3 web API, the logic is like below:
Step 1: access web api 1 to get the token
Step 2: access web api 2 to get the username/password by the token retrieved in Step 1
Step 3: access web API 3 to validate the user name/password in step 2
you can see we need to access those 3 API in order. as well know, window phone now access the network asynchronously, which causes a big challenge on make those API access in order, and which make the soure code hard to maintainace.
I also consider the synchronous source code like below, but I found there are some problems to access the network,many exeption will be thrown. For example, when an exception is thrown, I try to use asynchronous web request to access the same URL, it is OK. I am strugglig in it now. And I have to introduce thread to call it to avoid to block the UI thread.
internal static class HttpWebRequestExtensions
{
public const int DefaultRequestTimeout = 60000;
public static bool IsHttpExceptionFound = false;
public static WebResponse GetResponse(this WebRequest request, int nTimeOut = DefaultRequestTimeout)
{
var dataReady = new AutoResetEvent(false);
HttpWebResponse response = null;
var callback = new AsyncCallback(delegate(IAsyncResult asynchronousResult)
{
try
{
response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
dataReady.Set();
}
catch(Exception e)
{
IsHttpExceptionFound = true;
}
});
request.BeginGetResponse(callback, request);
if (dataReady.WaitOne(nTimeOut))
{
return response;
}
return null;
}
public static WebResponse PostRequest(this HttpWebRequest request, String postData, int nTimeOut = DefaultRequestTimeout)
{
var dataReady = new AutoResetEvent(false);
HttpWebResponse response = null;
var callback = new AsyncCallback(delegate(IAsyncResult asynchronousResult)
{
Stream postStream = request.EndGetRequestStream(asynchronousResult); //End the operation.
byte[] byteArray = Encoding.UTF8.GetBytes(postData); //Convert the string into a byte array.
postStream.Write(byteArray, 0, postData.Length); //Write to the request stream.
postStream.Close();
dataReady.Set();
});
request.BeginGetRequestStream(callback, request);
if (dataReady.WaitOne(nTimeOut))
{
response = (HttpWebResponse)request.GetResponse(nTimeOut);
if (IsHttpExceptionFound)
{
throw new HttpResponseException("Failed to get http response");
}
return response;
}
return null;
}
}
Any suggestion on using asynchronous web request to solve my case?
There's an example here of using asynchronous web services in a chained manner to call the Microsoft Translator service on WP7
Maybe it will give you some pointers?
http://blogs.msdn.com/b/translation/p/wp7translate.aspx
Related
I am trying to read request body in ActionFilter but having some strange errors.
What I tried so far:
Copying request body to memory stream
context.HttpContext.Request.Body.CopyTo(memoryStream)
Throws an error that only async operations are supported.
Copying request body to memory stream async
context.HttpContext.Request.Body.CopyToAsync(memoryStream).Wait()
Copies 0 bytes
Using BodyReader:
context.HttpContext.Request.BodyReader.AsStream(true).CopyToAsync(requestBody).Wait();
throws ArgumentOutOfRange exception 'Specified argument was out of the range of valid values. (Parameter 'start')'
I am using .net core 3.1
I had to convert my code to MiddleWare which is able to deal with Body stream:
MIddleware ccaptures request and put it to service.
Action filter access service and decides what to do with it.
Here is a code of middleware
public class RequestReaderMiddleWare
{
private readonly RequestDelegate _next;
public RequestReaderMiddleWare(RequestDelegate next)
{
_next = next;
}
public virtual async Task Invoke(HttpContext context)
{
//replace and revert original request stream
var requestBodyStream = new MemoryStream();
var originalRequestBody = context.Request.Body;
await context.Request.Body.CopyToAsync(requestBodyStream);
requestBodyStream.Seek(0, SeekOrigin.Begin);
var bodyContentService = context.RequestServices.GetService(typeof(BodyContentService))
as BodyContentService;
bodyContentService.Body = requestBodyStream.ToArray();
requestBodyStream.Seek(0, SeekOrigin.Begin);
context.Request.Body = requestBodyStream;
await _next(context);
context.Request.Body = originalRequestBody; //restore request body
}
}
PS: You need to register it in startup:
app.UseMiddleware<RequestReaderMiddleWare>();
I'm trying to use Flux to generate asynchronous server sent events using Flux.create. When my client connects the request eventually times out with no event ever received. I hard-coded in an event to be sent by the Flux.create just to see data flow, but still nothing received client side.
#GetMapping(path = "/stream", headers = "Accept=*/*", consumes = MediaType.ALL_VALUE, produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<ServerSentEvent<PricingDTO>> getEventStream() {
final Flux<ServerSentEvent<PricingDTO>> flux = Flux.<ServerSentEvent<PricingDTO>>create(emitter -> {
final PricingDTO pricing = new PricingDTO();
pricing.setId(99L);
emitter.next(ServerSentEvent.builder(pricing).build());
});
return flux;
}
Client side (Angular) code:
const eventSource = new EventSource(url);
eventSource.onmessage = (event) => {
console.debug('Received event: ' + event);
const json = JSON.parse(event.data);
// Should be PricingDTO record here
};
eventSource.onerror = (error) => {
if (eventSource.readyState === EventSource.CLOSED) {
console.log('The stream has been closed by the server.');
eventSource.close();
} else {
console.log('Error here: ' + error);
}
};
I never see an event come through the EventSource. Eventually the request times out and I see the error: net::ERR_EMPTY_RESPONSE
I'm new to using WebFlux and I suspect I'm missing some initialization on the FluxStream before I return the Flux result. I have debugged and do see the request being received by my web service and the Flux object being returned. Any idea why I'm not receiving my events?
Your webflux code seems fine. I tested this with the following simplified example (without your custom classes).
#SpringBootApplication
#RestController
public class App {
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
#GetMapping(path = "/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
public Flux<String> getEventStream() {
return Flux.create(emitter -> emitter.next("hi").next("hi2"));
}
}
When connecting to the steam in chrome you get to see the events coming in just fine:
data:hi
data:hi2
the problem either lies in your accept header filter, or on the client side. You could ofcourse validate this by connecting to your stream in a browser (or better, a test)
I'm trying to do repeat payments with Form Integration in Sagepay (now Opayo).
From an earlier problem posted on here, I get that the securitykey is needed but is not returned in the Form call, so an additional call needs to be made to the getTransactionDetails command.
I have the securitykey and can now make a call to https://test.sagepay.com/gateway/service/repeat.vsp to initiate the repeat payment. However, the documentation does not say where the response to that call goes. I assume therefore, that it would go to the NotificationURL that is set up with a payment when using the Server or Direct integrations. Since I'm using Form, this is not set.
The question is, is there any way of capturing the response to the https://test.sagepay.com/gateway/service/repeat.vsp call if the initial payment was created using Form integration?
I suppose the second question is, has anybody successfully made repeat payments work with Sagepay Form integration?
Not sure if this helps you and we didn't do repeat payments; but we are looking at releasing deferred payments and I think it is a similar approach.
How do you make the call to 'https://test.sagepay.com/gateway/service/repeat.vsp'?
Could you use a 'HttpWebRequest' to make the call then capture the direct response in 'HttpWebResponse'?
EG:
private static void DeferredSharedApiCall(Dictionary<string, string> data, string type, string url)
{
string postData = string.Join("&", data.Select(x => $"{x.Key}={HttpUtility.UrlEncode(x.Value)}"));
HttpWebRequest request = WebRequest.CreateHttp(url);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
using (TextWriter tw = new StreamWriter(request.GetRequestStream()))
{
tw.Write(postData);
}
HttpWebResponse response = null;
try
{
response = request.GetResponse() as HttpWebResponse;
}
catch (WebException ex)
{
//log.Error($"{type} Error, data: {postData}", ex);
}
catch (Exception ex)
{
//log.Error($"{type} Error, data: {postData}", ex);
}
if (response != null)
{
using (TextReader tr = new StreamReader(response.GetResponseStream()))
{
string result = tr.ReadToEnd();
//log.Info($"{type} Response: {Environment.NewLine}{result}");
}
}
}
I'm writing a simple Web API application using ASP.NET MVC 5 and Web API v2. The api should receive a binary file from a client that uses HttpClient in a Winforms application. The application and the web site should be running on a closed network with Active Directory.
The controller:
[Route("FileTest"]
public HttpResponseMessage PostTest([FromBody]HttpPostedFileBase file)
{
// does nothing just retuns ok
}
The client:
public void SendFile(string fileName)
{
using(FileStream fileStream = new FileStream(fileName, fileMode.open, FilleAccess.read))
{
using(MultipartFormDataContent data = new MultipartFormDataContent ())
{
using(StreamContent streamcontent = new StreamContent(fileStream))
{
data.Add(streamcontent );
HttpClient client = new HttpClient();
res = client .PostAsync("address", data).Result;
res.EnsureSucessStatusCode(); // exception unauthorized
}
}
}
Why is this not working?
HttpPostedFileBase is a MVC class, it is not a Web API class, so it is unlikely they will work together.
Instead of trying to pass the file as a parameter, just read the request content as a stream.
[Route("FileTest"]
public async Task<HttpResponseMessage> PostTest(HttpRequestMessage request)
{
var stream = await request.Content.ReadAsStreamAsync();
// ...
}
I've been racking my brain for a couple of days now on how to approach a new requirement.
I have two websites. The first one lets the user fill out an application. The second website is an internal website use to manage the users applications. I need to develop a "web service" that sends the application data from website 1 to website 2 and return a response to website 2 of success or failure. I have never done a web service before and I'm a bit confused on where to start. I've been reading various examples online but they all seem to be just a starting point for building a webservice... no specific examples.
So for posting the data website 1, what would my controller method look like? Do I use Json to post the data to website 2? What would and example of that look like? Is there some form of redirect in the method that points to website 2?
So for posting the response back to website 2 what would that controller method look like? I assume I would use Json again to send the response back to website 1? Is there some form of redirect in the method that points back to website 1?
I would use JSON and POST the application to the web service.
First I am assuming the application data is contained in some type of object. Use JSON.Net to serialize the object into JSON. It will look something like the following code.
var application = new Application();
string serializedApplication = JsonConvert.Serialize(application);
Second is to POST the code your endpoint(webservice, mvc action). To this you'll need to make a HTTPRequest to the endpoint. The following code is what I use to make to POST the code.
public bool Post(string url, string body)
{
//Make the post
ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, errors) => true;
var bytes = Encoding.Default.GetBytes(body);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
Stream stream = null;
try
{
request.KeepAlive = false;
request.ContentLength = bytes.Length;
request.ContentType = "application/x-www-form-urlencoded";
request.Timeout = -1;
request.Method = "POST";
stream = request.GetRequestStream();
stream.Write(bytes, 0, bytes.Length);
}
finally
{
if (stream != null)
{
stream.Flush();
stream.Close();
}
}
bool success = GetResponse(request);
return success;
}
public bool GetResponse(HttpWebRequest request)
{
bool success;
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
using (Stream responseStream = response.GetResponseStream())
{
if (response.StatusCode != HttpStatusCode.OK && response.StatusCode != HttpStatusCode.Created)
{
throw new HttpException((int)response.StatusCode, response.StatusDescription);
}
var end = string.Empty;
using (StreamReader reader = new StreamReader(responseStream))
{
end = reader.ReadToEnd();
reader.Close();
success = JsonConvert.DeserializeObject<bool>(end);
}
response.Close();
}
}
return success;
}
So now you have can POST JSON to an endpoint and receive a response the next step is to create the endpoint. The following code will get you started on an endpoint in mvc that will receive an application and process it.
[HttpPost]
public ActionResult SubmitApplication()
{
//Retrieve the POSTed payload
string body;
using (StreamReader reader = new StreamReader(Request.InputStream))
{
body = reader.ReadToEnd();
reader.Close();
}
var application = JsonConvert.Deserialize<Application>(body);
//Save the application
bool success = SaveApplication(application);
//Send the server a response of success or failure.
return Json(success);
}
The above code is a good start. Please note, I have not tested this code.
You have obviously more than one client for the data & operations. so a service is what you are looking for.
ASP.NET MVC is a good candidate for developing RESTful services. If you (and your Manager) are ready to use beta version, Then Checkout ASP.NET-Web API.
If you want to stay with a stable product, Go for MVC3. you may need to write some custom code to return the data in XML as well as JSON to server different kind of clients. There are some tutorials out there.
So create a Service (ASP.NET MVC / WCF Service) .You may then create 2 client apps, one for the external clients and another for the Internal users. Both of this apps can call methods in the Service to Create/ Read the user accounts / or whatever operation you want to do.
To make the apps more interactive and lively , you may conside including a wonderful thing called SiganalR, which helps you to get some real time data without continuosly polling the data base/ middle tier very in every n seconds !