I have an application on .Net Web API. After each action get executed, I want to take a look at result and change something in that.
Say my API controllerAction looks like
public Car Get()
{
...
}
After the action is executed, I want to modify the properties of return type in this case Car (but can be different for different action).
I know that IActionFilter.OnActionExecuted() gets called after an action gets executed. But I am not sure how to access the return type in this method.
You should be able to do this by looking at the response on the action executed context. If you want to get the car and modify it you could write something like this:
Car car;
if (actionExecutedContext.Response.TryGetContentValue<Car>(out car))
{
// modify the car to send back in the response
}
If you want to check the type of the response, you could write:
ObjectContent objectContent = actionExecutedContext.Response.Content as ObjectContent;
if (objectContent != null)
{
Type responseType = objectContent.ObjectType;
// do stuff with the type
}
Related
PUT, DELETE, POST can be operated as shown below.
By the way, I do not know how to do GET.
Please help me.
// PUT & DELETE (mapped to WRITE, DELETE of MD-SAL)
public void onDataTreeChanged(Collection<DataTreeModification<GreetingRegistry>> changes) {
for(DataTreeModification<GreetingRegistry> change: changes) {
DataObjectModification<GreetingRegistry> rootNode = change.getRootNode();
if(rootNode.getModificationType() == WRITE) {
...
}
else if(rootNode.getModificationType() == DELETE) {
...
}
}
// POST (mapped to RPC of MD-SAL)
public Future<RpcResult<HelloWorldOutput>> helloWorld(HelloWorldInput input)
{
HelloWorldOutputBuilder helloBuilder = new HelloWorldOutputBuilder();
helloBuilder.setGreeting("Hello " + input.getName());
return RpcResultBuilder.success(helloBuilder.build()).buildFuture();
}
// GET (???)
How should I implement it?
You don't actually have to implement anything for GET in your code, when you want to read from YANG modeled MD-SAL data, the GET method is be available by default, and returns whatever data you ask for in the URL. It is important to point to the correct URL.
If you want to do some processing on data before returning it to the user, you can use RPCs with POST, and do the processing in the RPC based methods. In your example above, you could pot the search keys into HelloWorldInput, do the processing in helloWorld(), and return results in HelloWorldOutput.
I have a MediaTypeFormatter that converts an internal rep of an image to a png/jpeg/etc. if someone asks for it. However, my WriteToStreamAsync never gets called unless I add an image/png or similar to the accept headers.
First, here is my webapi method, with some key bits removed for brevity:
public ImageFormatter.BinaryImage GetImage(int cId, int iId)
{
....
using (var input = iFIO.OpenRead())
{
input.Read(b.data, 0, (int)iFIO.Length);
}
// With this next line my mediatypeformatter is correctly called.
Request.Headers.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("image/png"));
return b;
}
And here is the write portion of my MediaTypeFormatter (there is also a read portion, and that works great, actually).
namespace PivotWebsite.MediaFormatters
{
public class ImageFormatter : MediaTypeFormatter
{
public class BinaryImage
{
public byte[] data;
public string metaData;
}
public ImageFormatter()
{
SupportedMediaTypes.Add(new MediaTypeHeaderValue("image/jpg"));
SupportedMediaTypes.Add(new MediaTypeHeaderValue("image/jpeg"));
SupportedMediaTypes.Add(new MediaTypeHeaderValue("image/png"));
}
public override bool CanWriteType(Type type)
{
return true;
}
public override async Task WriteToStreamAsync(Type type, object value, Stream writeStream, HttpContent content, TransportContext transportContext)
{
var b = value as BinaryImage;
if (b == null)
throw new InvalidOperationException("Can only work with BinaryImage types!");
await writeStream.WriteAsync(b.data, 0, b.data.Length);
}
}
}
What I expected to be able to do was, in WriteToStreamAsync, to alter the outgoing headers to include Content-Type as "image/png" (or whatever, depending on the data type).
However, when I call this from a web browser with a URL like "http://my.testdomain.net:57441/api/Images?cID=1&iID=1", the WriteToStreamAsync never gets called (accepted headers are listed as {text/html, application/xhtml+xml, */*}). If I add the line above that adds the proper image type, then everything is called as I would expect.
What am I missing here? The accepted header of "*/*" should have triggered my media formatter, right? Or... am I missing something basic about the plumbing in Web API.
Do you want the image formatter to always get used if the Accept header is "/"? If that's the case, then you should insert your formatter first in the Formatters collection like this:
config.Formatters.Insert(0, new ImageFormatter());
What happens when there isn't an exact Accept header match like in your case is that the first formatter that can write the type gets selected to serialize the object. So if you register your formatter first, it would get used.
This could have unintended side-effects because it would affect all your controllers though. I would suggest changing the CanWriteType implementation to only return true if it's a BinaryImage. That should make the formatter only get used when that's your return type.
Another thing you could do is select the formatter directly in your action by returning an HttpResponseMessage:
return Request.CreateResponse(HttpStatusCode.OK, image, new ImageFormatter());
That's basically saying "this action should always use the image formatter, regardless of content-type, accept headers etc". That might be reasonable in your case if you're always just returning an image and you need it serialized with your formatter.
I'm writing a CsvFormatter and I want to be able to call the API from the browser to trigger a file download. Since I didn't have control over the Accept header, I wanted to use an extension to trigger my CSV formatter, but the XML formatter kept getting the request. I found that by adding a "text/html" media type, I could handle the CSV extension. Hopefully this doesn't cause other problems down the line :).
public CsvFormatter()
{
var header = new MediaTypeHeaderValue("text/csv");
SupportedMediaTypes.Add(header);
MediaTypeMappings.Add(new UriPathExtensionMapping("csv", header));
// From Chrome: Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
// Allow the formatter to run from a standard browser request.
header = new MediaTypeHeaderValue("text/html");
SupportedMediaTypes.Add(header);
MediaTypeMappings.Add(new UriPathExtensionMapping("csv", header));
}
I have an Ajax request that sends some data to a page and expects back a truthy or falsey value depending on if the data was saved. In my controller I do everything and set the content to a true or false value. I really don't want to create a view just to output 1 variable, so I was wondering if there was a way that I don't have to use a view and only use the controller to output simple strings.
I believe you cannot disable views completely, but there's a pretty simple workaround: you can create one view and use it for many actions.
Let's say we've created the view views/main/ajax.cfm, what could be inside it? Obviously, simplest way is:
<cfoutput>#HTMLEditFormat(rc.response)#</cfoutput>
Personally I like returning JSON, it allows me to have status field, plus data, if needed. This way my view looks like this:
<cfheader name="Content-Type" value="application/json" />
<cfoutput>#SerializeJSON(rc.response)#</cfoutput>
Any way, now in our action we need to do something like this:
// prevent displaying the layout
request.layout = false;
// force special view
variables.fw.setView("main.ajax");
// init response (according to the choice made earlier)
rc.response["status"] = "OK";
rc.response = "";
There's one more gotcha for this. Sometimes you don't want AJAX page to be accessed directly (like opened in browser), or vise-versa -- want to do some debugging when it is.
There's a cool helper isAjax in CFWheels framework, it is easy to port to the FW/1. It could be as simple as adding method like this to controller:
/*
* Check if request is performed via AJAX
*/
private boolean function isAjax() {
return (cgi.HTTP_X_REQUESTED_WITH EQ "XMLHTTPRequest");
}
Actually, that setup code above is also helper method in my apps:
/*
* Set up for AJAX response
*/
private struct function setAjax() {
// prevent displaying the layout
request.layout = false;
// force special view
variables.fw.setView("main.ajax");
local.response["status"] = "OK";
return local.response;
}
So in my action code whole check looks like this, which is pretty compact and convenient:
if (isAjax()) {
rc.response = setAjax();
}
else {
return showNotFound();
}
Hope this helps.
You can't output directly from a Controller: its job is just to call the Model and pass data to the View, so you'll need a view template to do the outputting.
However, you can avoid having to create a separate view for each controller method by using the framework's setView() method. This allows you to override the convention and apply a single view to multiple controller methods. So you could set up a generic "ajax view" and then use it to output the data from any of your controllers:
views/main/ajax.cfm
<!---Prevent any layouts from being applied--->
<cfset request.layout=false>
<!--- Minimise white space by resetting the output buffer and only returning the following cfoutput --->
<cfcontent type="text/html; charset=utf-8" reset="yes"><cfoutput>#rc.result#</cfoutput>
controller.cfc
function init( fw )
{
variables.fw=arguments.fw;
return this;
}
function getAjaxResponse( rc )
{
rc.result=1;
fw.setView( "main.ajax" );
}
function getAnotherAjaxResponse( rc )
{
rc.result=0;
fw.setView( "main.ajax" );
}
You can use onMissingView in you Application.cfc to handle the response for ajax calls, this way you don't need to perform any extra logic in your controller methods.
// Application.cfc
function onMissingView(rc) {
if(structKeyExists(rc, "ajaxdata") && isAjaxRequest()) {
request.layout = false;
content type="application/json";
return serializeJSON(rc.ajaxdata);
}
else {
return view("main/notfound");
}
}
function isAjaxRequest() {
var headers = getHttpRequestData().headers;
return structKeyExists(headers, "X-Requested-With")
&& (headers["X-Requested-With"] eq "XMLHttpRequest");
}
// controller cfc
function dosomething(rc) {
rc.ajaxdata = getSomeService().doSomething();
}
This checks if the request context has an ajaxdata key, and is a genuine ajax request, then returns the serialize data. If it doesn't then it renders the main.notfound view
I upgraded from the ASP.NET Web API release on nuget.org (the version before the RC on Friday) to the nightly builds on myget.org. As expected there were many breaking changes, and one of them I can't seem to get around: We have a scenario where we want our action to return an object and set the status code to 201 Created. This was quite easily done before (might not compile - conceptual code from the top of my head):
Session session = GetSessionInfo(requestMessage);
var response = new HttpResonseMessage(HttpStatusCode.Created);
response.Content = response.CreateContent(session);
return response;
CreateContent was actually an extension method located in System.Net.Http.HttpResponseMessageExtensions calling an internal constructor in ObjectContent. With the new release HttpResponseMessageExtensions seems to be gone in the new release and so does the internal constructors of ObjectContent. Now it seems I must call an ObjectContent constructor, and the following seems to be the most appropriate for our needs:
public class ObjectContent<T> : ObjectContent
{
public ObjectContent(T value, MediaTypeFormatter formatter)
{
}
}
However it seems I have to pass a MediaTypeFormatter into it, mixing content negotiation into the logic of the action. In our setup content negotiation is generic and completely decoupled from the controllers.
Does anyone have a suggestion for solving the scenario to return an object, set the response status code, but not have to deal with MediaTypeFormatter, media type or any other content negotiation related stuff?
We redesigned how ObjectContent<T> creation works. Starting with the RC, you should be calling the CreateResponse() set of extension methods (they're off HttpRequestMessage). This will actually produce an instance of HttpResponseMessage with an instance of a content-negotiated ObjectContent<T> inside. So, something like:
Session session = GetSessionInfo(requestMessage);
var response = Request.CreateResponse(HttpStatusCode.Created, session);
return response;
If this was a regular post of a form I could go to Request.Form['somevalue'] and get the value. If this was a get with a query string I could go to Request.QueryString["somevalue"] and get the value.
Where is the raw data when you post an ajax request. I need a value out of the raw data string in a filter method.
Any help will be appreciated!!
Edits below:
public class ValidateAntiForgeryId : FilterAttribute, IAuthorizationFilter {
public void OnAuthorization(AuthorizationContext filterContext) {
if (filterContext == null) {
throw new ArgumentNullException("filterContext");
}
Guid filterGuid;
Guid.TryParse(filterContext.RequestContext.HttpContext.Request.Form["__sessionId"], out filterGuid);
if (filterGuid == Guid.Empty)
throw new AuthenticationException("Authentication failure");
try {
var cookieGuid = (Guid)filterContext.RequestContext.HttpContext.Items["SessionId"];
} catch {
throw new AuthenticationException("Authentication failure");
}
}
The posted data looks like this:
{"SsnLastFour":"2222","AccountNumber":"B112233","__sessionId":"dca0a504-3c40-4118-ae19-afefb9bfc8bd"}
I need access to the __sessionId chunk inside the filter.
There's nothing magic about AJAX posts. They're just plain old HTTP. That means you have plain old HTTP post values, and/or plainold HTTP Get values.
If you're not seeing them, it probably means you're not actually submitting them.
EDIT:
Two issues you did not include in your original question: 1) That this is JSON, and 2) That this is in an AuthorizationFilter (rather than an action method).
Both change the answers. Since ASP.NET does not natively understand JSON post values, you will have to parse them, via Request.InputStream. MVC3 by default has a JSON model binder, but AuthorizationFilters execute before model binders do, so you will be accessing things prior to the model binders being executed, and as such FormsCollection won't be populated (Request.Form[] won't work either, because as I said, asp.net doesn't natively understand JSON).
You may find that installing JSON.net via nuget may help with this task. Or you might just write a simple parse routine, since you know exactly what you're looking for.
You can accept the parameter values the same way you accept in normal form post.
Ex :
$.get("User/Get", { userId : "24"} ,function(data){
alert(data);
});
or
$("#yourDivId").load("User/Get?userId=23");
Your action method should look like
public ActionResult Get(int userId)
{
// you have value present in userId
if(Request.IsAjax())
{
return View("Partial/MyPartialView");
}
return View();
}
One thing you have to remember is, the parameter name of your action method should be same as of what your parameter/querystring name.
The fitlerContext has an ActionParameters collection which should have the parsed JSON properties (in case that helps). This may be easier than parsing the InputStream.
var sessionId = filterContext.ActionParameters["__sessionId"];