I have a MVC 4 application, using WebApi. An external client is POST'ing to it, and I need to collect that data. I can get model binding to work with
public void Post([FromBody] Alert alert) { ... }
where Alert is a class defining the complex type. However, I have a case where I want to read whatever is in the body, even when I don't know what the structure is. So how do I read the raw header and body of the incoming POST request. I tried with this:
public void Post(HttpContent content) { ... }
but when POST'ing to the service, the Post method does not get invoked at all.
Input?
Thanks
Try binding HttpRequestMessage instead of HttpContent. That should work and will give you access to the request headers and the body.
public void Post(HttpRequestMessage request) { ... }
You can also access the Request property on your controller which should be set correctly:
public void Post() { var content = Request.Content; }
Related
I am trying to access httpServletRequest inside a component class. I tried it in several ways.
#Component
public class MyService{
#Resource
WebServiceContext wsCtxt;
public void myWebMethod(){
MessageContext msgCtxt = wsCtxt.getMessageContext();
HttpServletRequest req = (
(HttpServletRequest)msgCtxt.get(MessageContext.SERVLET_REQUEST);
String clientIP = req.getRemoteAddr();
}
This didn't work for me. because WebServiceContext is always null. Then I tried same code inside Web service class. Then that code is working. My Requirement it to get HttpServletRequest inside component class. (ultimately What i am trying to do it get client host from request header).
It this possible to do ?. Are there any alternatives for this ?
Method #1
Have you tried passing the request object into your component by passing it in as an argument to your service method, and from your service to your component method?
// in your controller... Spring provides the request object
public String myController(HttpServletRequest request, ...) {
//...
myService.myServiceMethod(request,...);
}
// in your service...
public void myServiceMethod(HttpServletRequest request, ...) {
//...
myComponent.myWebMethod(request,...);
}
// in your component
public String myWebMethod(HttpServletRequest request, ...) {
// use the raw request object
}
Method #2
Also, DispatcherServlet exposes the request object by wrapping it in a ServletRequestAttributes object, which in turn is stored in a ThreadLocal variable. The actual storing takes place in RequestContextHolder and its static methods. You can access it as follows:
public void myWebMethod(){
//...
RequestAttributes reqAttr = RequestContextHolder.getRequestAttributes();
ServletRequestAttributes servlReqAttr = (ServletRequestAttributes)reqAttr;
HttpServletRequest req = servlReqAttr.getRequest();
//...
}
Although a little verbose, you can see what's going on.
You could also condense it:
((ServletRequestAttributes)RequestContextHolder.getRequestAttributes()).getRequest();
I hope this helps!
I'm trying to add custom http headers to a webview client (for authorization).
It seems to work in some cases, I'am able to login to a webpage without entering username and password, and I get redirected to another page. But when the page is calling other resources to get elements populated with data an error is thrown and OnReceivedHttpError is invoked. The error I'm getting is 401 unauthorized and when i look through the headers on the IWebResourceRequest i can't see the authorization headers at all.
Am I missing something or have anyone had same problems ?
Using Xamarin Forms 2.3.3.180 and targeting API 21 (Android 5.0 Lollipop), compile with Android 7.1 Nougat.
I've tried in postman to add headers to request and it works perfectly.
Renderer:
public class MyWebViewRenderer : WebViewRenderer
{
private MyWebViewClient _webViewClient;
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.WebView> e)
{
base.OnElementChanged(e);
if(_webViewClient == null)
_webViewClient = new MyWebViewClient();
Control.SetWebViewClient(_webViewClient);
Control.LongClickable = false;
Control.HapticFeedbackEnabled = false;
Control.Settings.JavaScriptEnabled = true;
var data = Encoding.GetEncoding("ISO-8859-1").GetBytes("username:password");
var base64string = Base64.EncodeToString(data, Base64Flags.NoWrap);
var headers = new Dictionary<string, string>();
headers.Add("Authorization", $"Basic {base64string}")
Control.LoadUrl(Control.Url, headers);
}
}
WebViewClient:
public override bool ShouldOverrideUrlLoading(WebView view, string url)
{
WebView.SetWebContentsDebuggingEnabled(true);
var data = Encoding.GetEncoding("ISO-8859-1").GetBytes("username:password");
var base64string = Base64.EncodeToString(data, Base64Flags.NoWrap);
var headers = new Dictionary<string, string>();
headers.Add("Authorization", $"Basic {base64string}")
view.LoadUrl(url, headers);
return true;
}
public override WebResourceResponse ShouldInterceptRequest(WebView view, IWebResourceRequest urlResource)
{
//headers does not always contains authorization header, so let's add it.
if (!urlResource.RequestHeaders.ContainsKey("authorization") && !urlResource.RequestHeaders.ContainsKey("Authorization"))
{
var data = Encoding.GetEncoding("ISO-8859-1").GetBytes("username:password");
var base64string = Base64.EncodeToString(data, Base64Flags.NoWrap);
urlResource.RequestHeaders.Add("Authorization", $"{base64string}");
}
return base.ShouldInterceptRequest(view, urlResource);
}
public override void OnReceivedHttpError(WebView view, IWebResourceRequest request, WebResourceResponse errorResponse)
{
base.OnReceivedHttpError(view, request, errorResponse);
}
If you only need the headers on the get requests, the code below will work. However POST requests are a different issue. I needed to do a similar thing (with all requests, not just GET), and all I can say is that there's not straightforward solution, at least not one that I've found (and I've tried everything short of writing my own network driver). I've tried so many methods (ShouldOverrideUrlLoading, ShouldInterceptRequest, custom LoadUrl and PostUrl etc.) and none of them give a 100% solution. There is a lot of misinformation about this so I think some clarification is needed since I've spent two days on this without success.
So here's what I've learned:
If you only need the headers in the GET requests, that's trivial. Simply create an implementation of WebViewClient and override ShouldOverrideUrlLoading like this:
[assembly: ExportRenderer(typeof(Xamarin.Forms.WebView), typeof(App.Android.HybridWebViewRenderer))]
namespace App.Android
{
public class HybridWebViewRenderer : WebViewRenderer
{
public HybridWebViewRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.WebView> e)
{
base.OnElementChanged(e);
Control.SetWebViewClient(new CustomWebViewClient());
}
}
public class CustomWebViewClient : WebViewClient
{
public override bool ShouldOverrideUrlLoading(Android.Webkit.WebView view, string url)
{
Dictionary<string, string> headers = new Dictionary<string, string>
{
["Name"] = "value"
};
view.LoadUrl(url, headers);
return true;
}
}
}
If, however, you need the headers in other requests (specifically POST requests) there really isn't a perfect solution. Many answers tell you to override ShouldInterceptRequest but this is unlikely to help. ShouldInterceptRequest provides an IWebResourceRequest which contains the URL of the request, the method (i.e. POST) and the headers. There are answers out there which state that adding the headers by doing request.Headers.Add("Name", "Value") is a viable solution but this is wrong. The IWebResourceRequest is not used by the WebView's internal logic so modifying it is useless!
You can write your own HTTP client in ShouldInterceptRequest which includes your own headers to perform the requests and return a WebResourceResponse object. Again, this works for GET requests, but the problem with this is that even though we can intercept a POST request, we cannot determine the content in the request as the request content is not included in the IWebResourceRequest object. As a result, we cannot accurately perform the request manually. So, unless the content of the POST request is unimportant or can somehow be fetched, this method is not viable.
An additional note on this method: returning null tells the WebView to handle the request for us. In other words 'I don't want to intercept the request'. If the return is not null however, the WebView will display whatever is in the WebResourceResponse object.
I also tried overriding the PostUrl and LoadUrl methods in the WebView itself. These methods are not called by the internal logic, so unless you are calling them yourself, this does not work.
So what can be done? There are a few hacky solutions (see github.com/KeejOow/android-post-webview) to get around this problem, but they rely on javascript and are not suitable in all cases (I have read that they don't work with forms). If you want to use them in Xamarin, you're going to need to adapt the code for C# anyway, and there is no guarantee that it will solve your problem.
I'm writing this so no one else has to waste countless hours finding a solution that doesn't really exist.
If only the Android devs had decided to include the POST content in the IWebResourceRequest object...
And apologies for the length, if you've read to this point, you're probably as desperate as I was.
This is more of a design related question, and any help/pointers in the right direction is highly appreciated.
I am working on a ASP.NET Web API2 application, and have an Authorization filter and other Action filters. Within these filters, I need to access the Request object that comes as a part of the HttpPost request body.
I use the following code to read the request body content and deserialize into the desired object. It works fine.
//actionContext is HttpActionContext
var requestContent = actionContext.Request.Content.ReadAsStringAsync();
var request = JsonSerializer.GetObject<BaseOTARequestModel>(requestContent.Result);
To serve a particular request, I am deserializing the request content twice (I have 2 filters). Once the request reaches the controller action, it is deserialized again by the Web API framework. I feel guilty that every request is deserialized 3 times, and have a feeling there is a better way to handle this.
How can I avoid deserializing the request multiple times in a request?
I took this on as a challenge and came up with this solution. Here's a base filter attribute class:
public abstract class BaseOTARequestFilterAttribute : ActionFilterAttribute
{
private HttpActionContext _actionContext;
protected BaseOTARequestModel RequestModel
{
get
{
if (_actionContext.Request.Properties.ContainsKey("RequestModel"))
{
return _actionContext.Request.Properties["RequestModel"] as BaseOTARequestModel;
}
return null;
}
set
{
_actionContext.Request.Properties["RequestModel"] = value;
}
}
public override void OnActionExecuting(HttpActionContext actionContext)
{
_actionContext = actionContext;
if (RequestModel == null)
{
//actionContext is HttpActionContext
var requestContent = actionContext.Request.Content.ReadAsStringAsync();
RequestModel = JsonSerializer.GetObject<BaseOTARequestModel>(requestContent.Result);
}
}
}
This base class handles your deserialization and uses the Request.Properties collection to store it. (OK, I know a Web API is stateless but this state only exists during the execution of the request so fine imho.)
Your various attributes should all inherit this base class and can use the derialized object as follows:
public override void OnActionExecuting(HttpActionContext actionContext)
{
base.OnActionExecuting(actionContext);
var data = RequestModel;
// etc.
}
This may not be the most elegant solution, but I believe it works. Interested to hear the views of others.
I am using Zuul to proxy a strange client that sends a body as part of a GET request. There is unfortunately no way I can change the client.
With curl such a request can be sent as:
curl -XGET 'localhost:8765/kibana/index.html' -d' {"key": "value"}'
And the data is really sent in the body. On zuul side, however, when I try to read the body it is empty. Here is my prototype zuul code:
#Configuration
#ComponentScan
#EnableAutoConfiguration
#Controller
#EnableZuulProxy
public class ZuulServerApplication {
#Bean
public ZuulFilter myFilter() {
return new ZuulFilter(){
#Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest request=(HttpServletRequest)ctx.getRequest();
try {
InputStream is=request.getInputStream();
String content=IOUtils.toString(is);
System.out.println("Request content:"+content);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
public boolean shouldFilter() {
return true;
}
#Override
public int filterOrder() {
return 10;
}
#Override
public String filterType() {
return "pre";
}};
}
public static void main(String[] args) {
new SpringApplicationBuilder(ZuulServerApplication.class).web(true).run(args);
}
}
If I send a POST request, the this code prints the request body without problem. However, if I send the above GET request, the body is not printed. Anything I can do to actually get the body sent as part of a GET request?
It seems that some underlying machinery[0], e.g. some built-in Zuul filter with lesser filter order, replaces default "raw" HttpServletRequest with HttpServletRequestWrapper which, under standard circumstances (i.e. not GET method with body), is able to handle multiple acquisition of input stream. But in the case of GET method with body HttpServletRequestWrapper seems to not proxy input stream at all.
Thus solution could be to change filterOrder e.g. to -10.
Then it works for the filter since HttpServletRequest is used - the mentioned machinery did not get to its turn and thus didn't replace HttpServletRequest with HttpServletRequestWrapper yet. But potential issue with this solution is that the filter might exhaust input stream for something else, e.g. filter with higher filter order. But since GET with body is not a good practice anyway, it might be good enough solution after all :)
[0] I've debug into this longer time ago, but did not get to exact point - thus vague definition of "the machinery".
I would like to capture and save in a log file all the requests that my WebAPI should handle.
Just tried to save the Request.Content from the controller constructor but unfortunately,
the request object is null from the controller constructor scope.
Hope to learn an efficient way to do it.
I would just hook into web api tracing...
http://www.asp.net/web-api/overview/testing-and-debugging/tracing-in-aspnet-web-api
From the above article, you can implement ITraceWriter like so. This example uses System.Diagnostics.Trace.WriteLine, but you could plug in writing to a file here as well.
public class SimpleTracer : ITraceWriter
{
public void Trace(HttpRequestMessage request, string category, TraceLevel level,
Action<TraceRecord> traceAction)
{
TraceRecord rec = new TraceRecord(request, category, level);
traceAction(rec);
WriteTrace(rec);
}
protected void WriteTrace(TraceRecord rec)
{
var message = string.Format("{0};{1};{2}",
rec.Operator, rec.Operation, rec.Message);
System.Diagnostics.Trace.WriteLine(message, rec.Category);
}
}
As you can see from the Trace method, you get access to the HttpRequestMessage here.
I ended up implementing middleware to deal with it.
public class GlobalRequestLogger : OwinMiddleware
{
public override Task Invoke(IOwinContext context)
{
// Implement logging code here
}
}
Then in your Startup.cs:
app.Use<GlobalRequestLogger>();