Looking to add the AuthorizeFilterAttribute or AnonymousFilterAttribute to an endpoint in Swashbuckle's implementation of Swagger so I can see which attribute is used on each endpoint in the generated documentation file in a running webapi that ends in /swagger. Is this currenlty possible?
I specifically would like to add a big bold label that says this endpoint is [Anonymous] or that endpoint is using [Authorize] and have them look differently that the summary or remark text.
Also I would like to be able to filter out all the different types of these restriction filter attributes for each endpoint including [NonAction], [Authorize], and [Anonymous] where one of these might be at the top of each controller endpoint. Maybe even eventually add other types of FilterAttributes besides these on each endpoint.
Currently it looks like only the HTTP Methods, the request and response objects can be retrieved in the current implementation so I was not able to find definitive information on this.
Since this is a Swagger implementation do these .NET specific attribute filters not translate to Swashbuckle b/c they only implement what's in the Swagger specification and nothing else?
Finally are their .NET specific extensions to Swashbuckle's implementation that do this?
Thanks!
For the part adding the label to unprotected methods/actions you could use an operation filter like this
public class UnprotectedOperationFilter : IOperationFilter
{
private bool HasAttribute(MethodInfo methodInfo, Type type, bool inherit)
{
// inhertit = true also checks inherited attributes
var actionAttributes = methodInfo.GetCustomAttributes(inherit);
var controllerAttributes = methodInfo.DeclaringType.GetTypeInfo().GetCustomAttributes(inherit);
var actionAndControllerAttributes = actionAttributes.Union(controllerAttributes);
return actionAndControllerAttributes.Any(attr => attr.GetType() == type);
}
public void Apply(Operation operation, OperationFilterContext context)
{
bool hasAuthorizeAttribute = HasAttribute(context.MethodInfo, typeof(AuthorizeAttribute), true);
bool hasAnonymousAttribute = HasAttribute(context.MethodInfo, typeof(AllowAnonymousAttribute), true);
// so far as I understood the action/operation is public/unprotected
// if there is no authorize or an allow anonymous (allow anonymous overrides all authorize)
bool isAuthorized = hasAuthorizeAttribute && !hasAnonymousAttribute;
if (!isAuthorized)
{
operation.Description =
"<p><bold>BIG BOLD LABEL indicating an UPROTECTED PUBLIC method</bold></p>"
+ operation.Description;
}
}
}
and add it with
services.AddSwaggerGen(c => { c.OperationFilter<UnprotectedOperationFilter>();} );
I didn't understand what you mean with filter out different attributes but I hope the code above helps you to check if the attribute is present and do what you desire to do.
I'm trying to serve an iCalendar file (.ics) in my MVC application.
So far it's working fine. I have an iPhone subscribing to the URL for the calendar but now I need to serve a personalised calendar to each user.
When subscribing to the calendar on the iPhone I can enter a username and password, but I don't know how to access these in my MVC app.
Where can I find details of how the authentication works, and how to implement it?
It turns out that Basic Authentication is what is required. I half had it working but my IIS configuration got in the way. So, simply returning a 401 response when there is no Authorization header causes the client (e.g. iPhone) to require a username/password to subscribe to the calendar.
On the authorization of the request where there is an Authorization request header, the basic authentication can be processed, retrieving the username and password from the base 64 encoded string.
Here's some useful code for MVC:
public class BasicAuthorizeAttribute : AuthorizeAttribute
{
public override void OnAuthorization(AuthorizationContext filterContext)
{
if (filterContext == null)
{
throw new ArgumentNullException("filterContext");
}
var auth = filterContext.HttpContext.Request.Headers["Authorization"];
if (!String.IsNullOrEmpty(auth))
{
var encodedDataAsBytes = Convert.FromBase64String(auth.Replace("Basic ", ""));
var value = Encoding.ASCII.GetString(encodedDataAsBytes);
var username = value.Substring(0, value.IndexOf(':'));
var password = value.Substring(value.IndexOf(':') + 1);
if (MembershipService.ValidateUser(username, password))
{
filterContext.HttpContext.User = new GenericPrincipal(new GenericIdentity(username), null);
}
else
{
filterContext.Result = new HttpStatusCodeResult(401);
}
}
else
{
if (AuthorizeCore(filterContext.HttpContext))
{
var cachePolicy = filterContext.HttpContext.Response.Cache;
cachePolicy.SetProxyMaxAge(new TimeSpan(0));
cachePolicy.AddValidationCallback(CacheValidateHandler, null);
}
else
{
filterContext.HttpContext.Response.Clear();
filterContext.HttpContext.Response.StatusDescription = "Unauthorized";
filterContext.HttpContext.Response.AddHeader("WWW-Authenticate", "Basic realm=\"Secure Calendar\"");
filterContext.HttpContext.Response.Write("401, please authenticate");
filterContext.HttpContext.Response.StatusCode = 401;
filterContext.Result = new EmptyResult();
filterContext.HttpContext.Response.End();
}
}
}
private void CacheValidateHandler(HttpContext context, object data, ref HttpValidationStatus validationStatus)
{
validationStatus = OnCacheAuthorization(new HttpContextWrapper(context));
}
}
Then, my controller action looks like this:
[BasicAuthorize]
public ActionResult Calendar()
{
var userName = HttpContext.User.Identity.Name;
var appointments = GetAppointments(userName);
return new CalendarResult(appointments, "Appointments.ics");
}
I found this really helpful, but i hit a few problems during the development and i thought i would share some of them to help save other people some time.
I was looking to get data from my web application into the calendar for an android device and i was using discountasp as a hosting service.
The first problem i hit was that the validation did not work when uploaded to the server, stangely enough it was accepting my control panel login for discountasp but not my forms login.
The answer to this was to turn off Basic Authentication in IIS manager. This resolved the issue.
Secondly, the app i used to sync the calendar to the android device was called iCalSync2 - its a nice app and works well. But i found that it only worked properly when the file was delivered as a .ics (duh for some reason i put it as a .ical.. it must have been late) and i also had to choose the webcal option
Lastly i found i had to add webcal:// to the start of my url instead of http://
Also be careful as the code posted above ignores the roles input variable and always passes nothing so you might need to do some role based checks inside your calendar routine or modify the code above to process the roles variable.
I want to prevent users submitting forms multiple times in .NET MVC. I've tried several methods using Javascript but have had difficulties getting it to work in all browsers. So, how can I prevent this in my controller? It there some way that multiple submissions can be detected?
Updated answer for ASP.NET Core MVC (.NET Core & .NET 5.0)
Update note: Remember ASP.NET Core is still called "Core" in .NET 5.0.
I'm going to stick to the least-impact use case like before, where you're only adorning those controller actions that you specifically want to prevent duplicate requests on. If you want to have this filter run on every request, or want to use async, there are other options. See this article for more details.
The new form tag helper now automatically includes the AntiForgeryToken so you no longer need to manually add that to your view.
Create a new ActionFilterAttribute like this example. You can do many additional things with this, for example including a time delay check to make sure that even if the user presents two different tokens, they aren't submitting multiple times per minute.
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public class PreventDuplicateRequestAttribute : ActionFilterAttribute {
public override void OnActionExecuting(ActionExecutingContext context) {
if (context.HttpContext.Request.HasFormContentType && context.HttpContext.Request.Form.ContainsKey("__RequestVerificationToken")) {
var currentToken = context.HttpContext.Request.Form["__RequestVerificationToken"].ToString();
var lastToken = context.HttpContext.Session.GetString("LastProcessedToken");
if (lastToken == currentToken) {
context.ModelState.AddModelError(string.Empty, "Looks like you accidentally submitted the same form twice.");
}
else {
context.HttpContext.Session.SetString("LastProcessedToken", currentToken);
}
}
}
}
By request, I also wrote an asynchronous version which can be found here.
Here's a contrived usage example of the custom PreventDuplicateRequest attribute.
[HttpPost]
[ValidateAntiForgeryToken]
[PreventDuplicateRequest]
public IActionResult Create(InputModel input) {
if (ModelState.IsValid) {
// ... do something with input
return RedirectToAction(nameof(SomeAction));
}
// ... repopulate bad input model data into a fresh viewmodel
return View(viewModel);
}
A note on testing: simply hitting back in a browser does not use the same AntiForgeryToken. On faster computers where you can't physically double click the button twice, you'll need to use a tool like Fiddler to replay your request with the same token multiple times.
A note on setup: Core MVC does not have sessions enabled by default. You'll need to add the Microsoft.AspNet.Session package to your project, and configure your Startup.cs properly. Please read this article for more details.
Short version of Session setup is:
In Startup.ConfigureServices() you need to add:
services.AddDistributedMemoryCache();
services.AddSession();
In Startup.Configure() you need to add (before app.UseMvc() !!):
app.UseSession();
Original answer for ASP.NET MVC (.NET Framework 4.x)
First, make sure you're using the AntiForgeryToken on your form.
Then you can make a custom ActionFilter:
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public class PreventDuplicateRequestAttribute : ActionFilterAttribute {
public override void OnActionExecuting(ActionExecutingContext filterContext) {
if (HttpContext.Current.Request["__RequestVerificationToken"] == null)
return;
var currentToken = HttpContext.Current.Request["__RequestVerificationToken"].ToString();
if (HttpContext.Current.Session["LastProcessedToken"] == null) {
HttpContext.Current.Session["LastProcessedToken"] = currentToken;
return;
}
lock (HttpContext.Current.Session["LastProcessedToken"]) {
var lastToken = HttpContext.Current.Session["LastProcessedToken"].ToString();
if (lastToken == currentToken) {
filterContext.Controller.ViewData.ModelState.AddModelError("", "Looks like you accidentally tried to double post.");
return;
}
HttpContext.Current.Session["LastProcessedToken"] = currentToken;
}
}
}
And on your controller action you just...
[HttpPost]
[ValidateAntiForgeryToken]
[PreventDuplicateRequest]
public ActionResult CreatePost(InputModel input) {
...
}
You'll notice this doesn't prevent the request altogether. Instead it returns an error in the modelstate, so when your action checks if ModelState.IsValid then it will see that it is not, and will return with your normal error handling.
I've tried several methods using Javascript but have had difficulties getting it to work in all browsers
Have you tried using jquery?
$('#myform').submit(function() {
$(this).find(':submit').attr('disabled', 'disabled');
});
This should take care of the browser differences.
Just to complete the answer of #Darin, if you want to handle the client validation (if the form has required fields), you can check if there's input validation error before disabling the submit button :
$('#myform').submit(function () {
if ($(this).find('.input-validation-error').length == 0) {
$(this).find(':submit').attr('disabled', 'disabled');
}
});
What if we use $(this).valid()?
$('form').submit(function () {
if ($(this).valid()) {
$(this).find(':submit').attr('disabled', 'disabled');
}
});
Strategy
The truth is that you need several lines of attack for this problem:
The Post/Redirect/Get (PRG) pattern is not enough by itself. Still, it should always be used to provide the user with good experiences when using back, refresh, etc.
Using JavaScript to prevent the user from clicking the submit button multiple times is a must because it provides a much less jarring user experience compared to server-side solutions.
Blocking duplicate posts solely on the client side doesn't protect against bad actors and does not help with transient connection problems. (What if your first request made it to the server but the response did not make it back to the client, causing your browser to automatically resend the request?)
I'm not going to cover PRG, but here are my answers for the other two topics. They build upon the other answers here. FYI I'm using .NET Core 3.1.
Client-Side
Assuming you are using jQuery validation, I believe this is the cleanest/most efficient way to prevent your form submit button from being double-clicked. Note that submitHandler is only called after validation has passed, so there is no need to re-validate.
$submitButton = $('#submitButton');
$('#mainForm').data('validator').settings.submitHandler = function (form) {
form.submit();
$submitButton.prop('disabled', true);
};
An alternative to disabling the submit button is to show an overlay in front of the form during submission to 1) block any further interaction with the form and 2) communicate that the page is "doing something." See this article for more detail.
Server-Side
I started off with Jim Yarbro's great answer above, but then I noticed Mark Butler's answer pointing out how Jim's method fails if someone submits forms via multiple browser tabs (because each tab has a different token and posts from different tabs can be interlaced). I confirmed that such a problem really does exist and then decided to upgrade from tracking just the last token to tracking the last x tokens.
To facilitate that, I made a couple of helper classes: one for storing the last x tokens and one for making it easy to store/retrieve objects to/from session storage. The main code now checks that the current token is not found in the token history. Other than that, the code is pretty much the same. I just made some little tweaks to suit my tastes. I included both the regular and asynchronous versions. The full code is below, but these are the critical lines:
var history = session.Get<RotatingHistory<string>>(HistoryKey) ?? new RotatingHistory<string>(HistoryCapacity);
if (history.Contains(token))
{
context.ModelState.AddModelError("", DuplicateSubmissionErrorMessage);
}
else
{
history.Add(token);
}
Sadly, the fatal flaw of this approach is that the feedback from the first post (before any duplicates) gets lost. A better (but much more complex) solution would be to store the result of each unique request by GUID, and then handle duplicate requests by not only skipping doing the work again but also returning the same result from the first request, giving the user a seamless experience. This thorough article detailing Air BnB's methods of avoiding duplicate payments will give you an idea of the concepts.
PreventDuplicateFormSubmissionAttribute.cs
using System;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc.Filters;
// This class provides an attribute for controller actions that flags duplicate form submissions
// by adding a model error if the request's verification token has already been seen on a prior
// form submission.
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public class PreventDuplicateFormSubmissionAttribute: ActionFilterAttribute
{
const string TokenKey = "__RequestVerificationToken";
const string HistoryKey = "RequestVerificationTokenHistory";
const int HistoryCapacity = 5;
const string DuplicateSubmissionErrorMessage =
"Your request was received more than once (either due to a temporary problem with the network or a " +
"double button press). Any submissions after the first one have been rejected, but the status of the " +
"first one is unclear. It may or may not have succeeded. Please check elsewhere to verify that your " +
"request had the intended effect. You may need to resubmit it.";
public override void OnActionExecuting(ActionExecutingContext context)
{
HttpRequest request = context.HttpContext.Request;
if (request.HasFormContentType && request.Form.ContainsKey(TokenKey))
{
string token = request.Form[TokenKey].ToString();
ISession session = context.HttpContext.Session;
var history = session.Get<RotatingHistory<string>>(HistoryKey) ?? new RotatingHistory<string>(HistoryCapacity);
if (history.Contains(token))
{
context.ModelState.AddModelError("", DuplicateSubmissionErrorMessage);
}
else
{
history.Add(token);
session.Put(HistoryKey, history);
}
}
}
public override async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
{
HttpRequest request = context.HttpContext.Request;
if (request.HasFormContentType && request.Form.ContainsKey(TokenKey))
{
string token = request.Form[TokenKey].ToString();
ISession session = context.HttpContext.Session;
await session.LoadAsync();
var history = session.Get<RotatingHistory<string>>(HistoryKey) ?? new RotatingHistory<string>(HistoryCapacity);
if (history.Contains(token))
{
context.ModelState.AddModelError("", DuplicateSubmissionErrorMessage);
}
else
{
history.Add(token);
session.Put(HistoryKey, history);
await session.CommitAsync();
}
await next();
}
}
}
RotatingHistory.cs
using System.Linq;
// This class stores the last x items in an array. Adding a new item overwrites the oldest item
// if there is no more empty space. For the purpose of being JSON-serializable, its data is
// stored via public properties and it has a parameterless constructor.
public class RotatingHistory<T>
{
public T[] Items { get; set; }
public int Index { get; set; }
public RotatingHistory() {}
public RotatingHistory(int capacity)
{
Items = new T[capacity];
}
public void Add(T item)
{
Items[Index] = item;
Index = ++Index % Items.Length;
}
public bool Contains(T item)
{
return Items.Contains(item);
}
}
SessonExtensions.cs
using System.Text.Json;
using Microsoft.AspNetCore.Http;
// This class is for storing (serializable) objects in session storage and retrieving them from it.
public static class SessonExtensions
{
public static void Put<T>(this ISession session, string key, T value) where T : class
{
session.SetString(key, JsonSerializer.Serialize(value));
}
public static T Get<T>(this ISession session, string key) where T : class
{
string s = session.GetString(key);
return s == null ? null : JsonSerializer.Deserialize<T>(s);
}
}
You could include a hidden (random or counter) value in the form post, a controller could track these values in an 'open' list or something similar; every time your controller hands out a form it embeds a value, which it tracks allowing one post use of it.
In its self, no, however depending on what the controller is actually doing, you should be able to work out a way.
Is a record being created in the database that you can check for to see if they've already submitted the form?
Just add this code at the end of your page. I am using "jquery-3.3.1.min.js" and "bootstrap 4.3.1"
<script type="text/javascript">
$('form').submit(function () {
if ($(this).valid()) {
$(this).find(':submit').attr('disabled', 'disabled');
}
});
</script>
Use the Post/Redirect/Get design pattern.
PS:
It looks to me that the answer by Jim Yarbro could have a fundamental flaw in that the __RequestVerificationToken stored in the HttpContext.Current.Session["LastProcessedToken"] will be replaced when a second form is submitted (from say another browser window). At this point, it is possible to re-submit the first form without it being recognized as a duplicate submission. For the proposed model to work, wouldn’t a history of __RequestVerificationToken be required? This doesn't seem feasible.
Dont reinvent the wheel :)
Use the Post/Redirect/Get design pattern.
Here you can find a question and an answer giving some suggestions on how to implement it in ASP.NET MVC.
You can also pass some sort of token in a hidden field and validate this in the controller.
Or you work with redirects after submitting values. But this get's difficult if you take heavily advantage of ajax.
This works on every browser
document.onkeydown = function () {
switch (event.keyCode) {
case 116: //F5 button
event.returnValue = false;
event.keyCode = 0;
return false;
case 82: //R button
if (event.ctrlKey) {
event.returnValue = false;
event.keyCode = 0;
return false;
}
}
}
You can do this by creating some sort of static entry flag that is user specific, or specific to whatever way you want to protect the resource. I use a ConcurrentDictionary to track entrance. The key is basically the name of the resource I'm protecting combined with the User ID. The trick is figuring out how to block the request when you know it's currently processing.
public async Task<ActionResult> SlowAction()
{
if(!CanEnterResource(nameof(SlowAction)) return new HttpStatusCodeResult(204);
try
{
// Do slow process
return new SlowProcessActionResult();
}
finally
{
ExitedResource(nameof(SlowAction));
}
}
Returning a 204 is a response to the double-click request that will do nothing on the browser side. When the slow process is done, the browser will receive the correct response for the original request and act accordingly.
Use this simple jquery input field and will work awesomely even if you have multiple submit buttons in a single form.
$('input[type=submit]').click(function () {
var clickedBtn = $(this)
setTimeout(function () {
clickedBtn.attr('disabled', 'disabled');
}, 1);
});
I have a registration form for a website that needs to check if an email address already exists for a given company id. When the user tabs or clicks out of the email field (blur event), I want jQuery to go off and do an AJAX request so I can then warn the user they need to pick another address.
In my controller, I have a method such as this:
public JsonResult IsEmailValid(int companyId, string customerNumber)
{
return Json(...);
}
To make this work, I will need to update my routes to point directly to /Home/IsEmailValid and the two parameters {companyId} and {customerNumber}. This seems like I'm "hacking" around in the routing system and I'm guessing perhaps there is a cleaner alternative.
Is there a "proper" or recommended way to accomplish this task?
EDIT: What I meant by the routes is that passing in extra parameter ({customerNumber}) in the URL (/Home/IsEmailValid/{companyId}/{customerNumber}) won't work with the default route mapping.
You can use the jQuery Validation Plugin to do that.
You're gonna have to implement your own method though like this :
$.validator.addMethod("checkCompanyEmail", function(value, element) {
var email = value;
var companyID = //get the companyID
var result;
//post the data to server side and process the result and return it
return result;
}, "That company email is already taken.");
Then register your validation method :
$("#the-form").validate({
rules: { email: { required: true, "checkCompanyEmail" : true } }
});
PS. I don't understand why you need to "hack around" with routing for that.
from the validate documentation under remote method
remote: {
url: "check-email.php",
type: "post",
data: {
username: function() {
return $("#username").val();
}
}
}
I want to create dynamic content based on this. I know it's somewhere, as web analytics engines can get this data to determine how people got to your site (referrer, search terms used, etc.), but I don't know how to get at it myself.
You can use the "referer" part of the request that the user sent to figure out what he searched for. Example from Google:
http://www.google.no/search?q=stack%20overflow
So you must search the string (in ASP(.NET) this can be found be looking in Request.Referer) for "q=" and then URLDecode the contents.
Also, you should take a look at this article that talks more about referrers and also other methods to track your visitors:
http://www.15seconds.com/issue/021119.htm
This is some code to backup the idea of using a querystring method and if that's not available using the UrlReferrer property of the Request object. This can then be stashed in a session object (or somewhere else if that works better for you) so that you can track the source between pages. (Page_Load doesn't seem to be formatted correctly inside the code sample here)
public void Page_Load(Object Sender, EventArgs E) {
if (null == Session["source"] || Session["source"].ToString().Equals(string.Empty)) {
if (Request.QueryString["src"] != null) {
Session["source"] = Server.UrlDecode(Request.QueryString["src"].ToString());
} else {
if (Request.UrlReferrer != null) {
Session["source"] = Request.UrlReferrer.ToString();
} else {
Session["source"] = string.Empty;
}
}
}}