IIS returning a page in response.responseText - asp.net

A user attempted to upload a file that was too large (70MB for a single PDF page) and the system errored out. This is correct and expected behavior, however in the response.responseText (in a jQuery AJAX call) instead of just being the message, it was raw text of an entire html page, cut off at a certain point, which I believe coincides with the default style of IIS error pages.
I do not want to increase the limit of the file size to allow the file to come through, but I do wish to make it to where response.responseText just returns the message (effectively, what's between the < title > < /title > tags).
I attempted to set breakpoints in the upload.ashx file to see if I could find where this was happening, but it never gets that far (if it is a normal file, these breakpoints hit). Which is fine, I'm okay with IIS gatekeeping (I imagine if I try to bypass IIS for handling it, the file is going to get uploaded to the server and then rejected. Plus, lose out on just letting IIS configuration handle this), but I don't want to return an entire page if possible.
To my mind, the resolution I see is to see if response.responseText contains DOCTYPE and if so, scrape what is inside the title tag, but I feel like there may be a more by the book way of doing this?
edit: I did see where someone recommended setting existingResponse="PassThrough" on the httpErrors section of web.config, but when I did this the responseText just became blank and it still didn't touch breakpoints so I don't think this is achieving what I'm after.

This probably isn't the best way to handle, but seems to work in this case so just running with it:
changed:
error: function (response) {
alert(response.responseText);
}
to:
error: function (response) {
var titleIndex = response.responseText.indexOf('<title>');
var titleEndIndex = response.responseText.indexOf('</title>');
var message = response.responseText.substr(titleIndex + 7, titleEndIndex - titleIndex - 7);
alert(message);
}
which returns "IIS 10.0 Detailed Error - 413.1 - Request Entity Too Large" in this particular instance.

Related

Semantic-ui Form Validation basic setup

I'm new to semantic-ui and to javascript as well, so please bear with me. I have a basic form that I'm trying to get working with the built-in form validation semantic-ui provides. This form is part of a web app using node, express, and pug. The structure of the specific form (view) I'm working on looks like this:
Sorry for using a picture but I'm trying to keep this high-level.
As you can see, I have a form (with I believe the requisite classes), a submit button and a script block at the end, which is where I've got the validation code at the moment.
Here's my validation code such as it is:
$('#new-password-form').form({
on: 'blur',
fields: {
password: {
identifier : 'password',
rules: [
{
type : 'empty',
prompt: 'You must enter a password'
},
{
type : 'regExp[/^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[!##\$%\^&\*])(?=.{8,})/]',
prompt: 'Your password must be at least 8 characters long, and contain upper and lower case characters, digit(s), and symbol(s)'
}
]
}
}
}, {
onSuccess : function(e){
e.preventDefault();
}
});
The trouble is, validation isn't working. When I click the submit button the form attempts a regular get submit and it's as if the javascript isn't even there somehow. Yet it is there. Node is showing everything is properly fetched and loaded by the browser. Inspecting the rendered HTML shows everything is there, and I see no errors in the console. The page appears to have loaded all the requisite files successfully as follows:
GET /enroll/new 200 31.281 ms - 2652
GET /stylesheets/style.css 200 0.859 ms - 735
GET /jquery/jquery.js 200 1.491 ms - 280364
GET /ui/semantic.min.css 200 1.508 ms - 628536
GET /ui/semantic.min.js 200 2.070 ms - 275709
GET /images/amm.png 200 2.068 ms - 25415
GET /ui/semantic.min.css 200 0.418 ms - 628536
GET /favicon.ico 404 9.768 ms - 1499
So what gives? Can someone tell me what I'm doing wrong? Happy to provide more detail if what I have here isn't enough.
Update:
I extracted the HTML to a flat file, and relinked the assets (png, js, css) so there is no server involved at all. The page loads in the browser just fine. I get the exact same behavior (nothing happens when submit is clicked except the page reloads with get parameters—default non-js behavior AFAIK). It's making me think something is wrong with jQuery or javascript itself.
Well I found the problem... a missing ',' at the end of the "type:" row (regExp[/^(?=.*[a-z])...).
Now validation is working for both the static file, and the server version. For what it's worth coming from other languages where this is not an issue, javascript's ubiquitous use of inline functions and data structures nested multiple levels deep is something I've had a very hard time getting used to. Makes it all too easy to miss some critical little piece.
I guess let this be another example of a basic setup of semantic-ui that works... so long as you don't leave off any commas. (I fixed the code above for those that might want to copy/paste)

Google reCAPTCHA response success: false, no error codes

UPDATE: Google has recently updated their error message with an additional error code possibility: "timeout-or-duplicate".
This new error code seems to cover 99% of our previously mentioned mysterious
cases.
We are still left wondering why we get that many validation requests that are either timeouts or duplicates. Determinining this with certainty is likely to be impossible, but now I am just hoping that someone else has experienced something like it.
Disclaimer: I cross posted this to Google Groups, so apologies for spamming the ether for the ones of you who frequent both sites.
I am currently working on a page as part of a ASP.Net MVC application with a form that uses reCAPTCHA validation. The page currently has many daily users.
In my server side validation** of a reCAPTCHA response, for a while now, I have seen the case of the reCAPTCHA response having its success property set to false, but with an accompanying empty error code array.
Most of the requests pass validation, but some keep exhibiting this pattern.
So after doing some research online, I explored the two possible scenarios I could think of:
The validation has timed out and is no longer valid.
The user has already been validated using the response value, so they are rejected the second time.
After collecting data for a while, I have found that all cases of "Success: false, error codes: []" have either had the validation be rather old (ranging from 5 minutes to 10 days(!)), or it has been a case of a re-used response value, or sometimes a combination of the two.
Even after implementing client side prevention of double-clicking my submit-form button, a lot of double submits still seem to get through to the server side Google reCAPTCHA validation logic.
My data tells me that 1.6% (28) of all requests (1760) have failed with at least one of the above scenarios being true ("timeout" or "double submission").
Meanwhile, not a single request of the 1760 has failed where the error code array was not empty.
I just have a hard time imagining a practical use case where a ChallengeTimeStamp gets issued, and then after 10 days validation is attempted, server side.
My question is:
What could be the reason for a non-negligible percentage of all Google reCAPTCHA server side validation attempts to be either very old or a case of double submission?
**By "server side validation" I mean logic that looks like this:
public bool IsVerifiedUser(string captchaResponse, string endUserIp)
{
string apiUrl = ConfigurationManager.AppSettings["Google_Captcha_API"];
string secret = ConfigurationManager.AppSettings["Google_Captcha_SecretKey"];
using (var client = new HttpClient())
{
var parameters = new Dictionary<string, string>
{
{ "secret", secret },
{ "response", captchaResponse },
{ "remoteip", endUserIp },
};
var content = new FormUrlEncodedContent(parameters);
var response = client.PostAsync(apiUrl, content).Result;
var responseContent = response.Content.ReadAsStringAsync().Result;
GoogleCaptchaResponse googleCaptchaResponse = JsonConvert.DeserializeObject<GoogleCaptchaResponse>(responseContent);
if (googleCaptchaResponse.Success)
{
_dal.LogGoogleRecaptchaResponse(endUserIp, captchaResponse);
return true;
}
else
{
//Actual code ommitted
//Try to determine the cause of failure
//Look at googleCaptchaResponse.ErrorCodes array (this has been empty in all of the 28 cases of "success: false")
//Measure time between googleCaptchaResponse.ChallengeTimeStamp (which is UTC) and DateTime.UtcNow
//Check reCAPTCHAresponse against local database of previously used reCAPTCHAresponses to detect cases of double submission
return false;
}
}
}
Thank you in advance to anyone who has a clue and can perhaps shed some light on the subject.
You will get timeout-or-duplicate problem if your captcha is validated twice.
Save logs in a file in append mode and check if you are validating a Captcha twice.
Here is an example
$verifyResponse = file_get_contents('https://www.google.com/recaptcha/api/siteverify?secret='.$secret.'&response='.$_POST['g-recaptcha-response'])
file_put_contents( "logfile", $verifyResponse, FILE_APPEND );
Now read the content of logfile created above and check if captcha is verified twice
This is an interesting question, but it's going to be impossible to answer with any sort of certainly. I can give an educated guess about what's occurring.
As far as the old submissions go, that could simply be users leaving the page open in the browser and coming back later to finally submit. You can handle this scenario in a few different ways:
Set a meta refresh for the page, such that it will update itself after a defined period of time, and hopefully either get a new ReCAPTCHA validation code or at least prompt the user to verify the CAPTCHA again. However, this is less than ideal as it increases requests to your server and will blow out any work the user has done on the form. It's also very brute-force: it will simply refresh after a certain amount of time, regardless of whether the user is currently actively using the page or not.
Use a JavaScript timer to notify the user about the page timing out and then refresh. This is like #1, but with much more finesse. You can pop a warning dialog telling the user that they've left the page sitting too long and it will soon need to be refreshed, giving them time to finish up if they're actively using it. You can also check for user activity via events like onmousemove. If the user's not moving the mouse, it's very likely they aren't on the page.
Handle it server-side, by catching this scenario. I actually prefer this method the most as it's the most fluid, and honestly the easiest to achieve. When you get back success: false with no error codes, simply send the user back to the page, as if they had made a validation error in the form. Provide a message telling them that their CAPTCHA validation expired and they need to verify again. Then, all they have to do is verify and resubmit.
The double-submit issue is a perennial one that plagues all web developers. User behavior studies have shown that the vast majority occur because users have been trained to double-click icons, and as a result, think they need to double-click submit buttons as well. Some of it is impatience if something doesn't happen immediately on click. Regardless, the best thing you can do is implement JavaScript that disables the button on click, preventing a second click.

What keeps caching from working in WebMatrix?

I have a number of pages in a WebMatrix Razor ASP.Net site where I have added one line of code:
Response.OutputCache(600);
From reading about it I had assumed that this mean that IIS would create a cache of the html produced by the page, serve that html for the next 10 minutes, and after 10 minutes when the next request came in, it would run the code again.
Now the page is being fetched as part of an timed jquery call. The time code in the client runs every minute. The code there is very simple:
function wknTimer4() {
$.get('PerfPanel', function(data) {
$('#perfPanel').html(data);
});
It occasionally appears to cache, but when i look at the number of database queries done during the 10 minute period, i might have well over 100 database queries. I know the caching isn't working the way I expect. Does the cache only work for a single session? Is there some other limitation?
Update: it really shouldn't matter what the client does, whether it fetches the page through a jQuery call, or straight html. If the server is caching, it doesn't matter what the client does.
Update 2: complete code dumped here. Boring stuff:
#{
var db = Database.Open("LOS");
var selectQueryString = "SELECT * FROM LXD_funding ORDER BY LXDOrder";
// cache the results of this page for 600 seconds
Response.OutputCache(600);
}
#foreach (var row in db.Query(selectQueryString) ){
<h1>
#row.quotes Loans #row.NALStatus, oldest #(NALWorkTime.WorkDays(row.StatusChange,DateTime.Now)) days
</h1>
}
Your assumptions about how OutputCache works are correct. Can you check firebug or chrome tools to look at the outgoing requests hitting your page? If you're using jQuery, sometimes people set the cache property on the $.get or $.ajax to false, which causes the request to the page to have a funky trailing querystring. I've made the mistake of setting this up globally to fix some issues with jQuery and IE:
http://api.jquery.com/jQuery.ajaxSetup/
The other to look at here is the grouping of DB calls. Are you just making a lot of calls with one request? Are you executing a db command in a loop, within another reader? Code in this case would be helpful.
Good luck, I hope this helps!

as3 to .net, not receiving Event.COMPLETE callback

I created an image uploader for an app I am working on. I first used php for the server side script, and everything worked fine. I found out afterwards I had to use .net, so I created new serverside scripts. The problem I am having is that my event.COMPLETE listener is never firing. I can receive data back using a DATAEVENT listener, but then it stops at this error:
Error #2044: Unhandled IOErrorEvent:. text=Error #2036: Load Never Completed.
Here is how I am sending my file.
var fileRefReq:URLRequest = new URLRequest(FILE_UPLOAD_TEMP);
var fileReqVars:URLVariables = new URLVariables();
fileReqVars.subdir = "Temp";
fileRefReq.data = fileReqVars;
fileRefReq.method = URLRequestMethod.POST;
fileRef.upload(fileRefReq);
The file definitely gets uploaded to the first TEMP directory, but then it breaks with the above error.
Has anyone else had a similar problem or point me in the right direction for solving this?
This is an error produced by Flash. The most common causes are:
It could be a 404 Error you are getting somewhere in the Flash.
This error can occur if you close the browser while it is loading something.
By default, the calling SWF file and the URL you load must be in the same domain. For example, a SWF file at www.adobe.com can load data only from sources that are also at www.adobe.com. To load data from a different domain, place a URL policy file on the server hosting the data.
Number 3 is important because a common user problem with Flash is security issues - so it is just something to rule out. Most likely not the cause here.
I would test for these 3 causes and read over the URLRequest: http://livedocs.adobe.com/flex/3/langref/flash/net/URLRequest.html
After some additional thought I think it is timing out but that is just a theory. Add an event listener like so:
urlLoader.addEventListener("httpResponseStatus", function(event:HTTPStatusEvent):void
to see what is actually happening.
You have to handle the event such as:
// add the event listener
urlLoader.addEventListener( IOErrorEvent.IO_ERROR, onErrorHandler );
// handle the error event like this:
private function onErrorHandler( e: IOErrorEvent ): void {
trace( "An io error occurred." );
}
Hope that helps

How would you handle errors when using jQuery.ajax()?

When using jQuery's ajax method to submit form data, what is the best way to handle errors?
This is an example of what a call might look like:
$.ajax({
url: "userCreation.ashx",
data: { u:userName, p:password, e:email },
type: "POST",
beforeSend: function(){disableSubmitButton();},
complete: function(){enableSubmitButton();},
error: function(xhr, statusText, errorThrown){
// Work out what the error was and display the appropriate message
},
success: function(data){
displayUserCreatedMessage();
refreshUserList();
}
});
The request might fail for a number of reasons, such as duplicate user name, duplicate email address etc, and the ashx is written to throw an exception when this happens.
My problem seems to be that by throwing an exception the ashx causes the statusText and errorThrown to be undefined.
I can get to the XMLHttpRequest.responseText which contains the HTML that makes up the standard .net error page.
I am finding the page title in the responseText and using the title to work out which error was thrown. Although I have a suspicion that this will fall apart when I enable custom error handling pages.
Should I be throwing the errors in the ashx, or should I be returning a status code as part of the data returned by the call to userCreation.ashx, then using this to decide what action to take?
How do you handle these situations?
For debugging, I usually just create an element (in the case below: <div id="error"></div>) on the page and write the XmlHttpRequest to it:
error: function (XMLHttpRequest, textStatus, errorThrown) {
$("#error").html(XMLHttpRequest.status + "\n<hr />" + XMLHttpRequest.responseText);
}
Then you can see the types of errors that are occurring and capture them correctly:
if (XMLHttpRequest.status === 404) // display some page not found error
if (XMLHttpRequest.status === 500) // display some server error
In your ashx, can you throw a new exception (e.g "Invalid User" etc.) and then just parse that out of the XMLHttpRequest.responseText? For me when I get an error the XMLHttpRequest.responseText isn't the standard Asp.Net error page, it's a JSON object containing the error like this:
{
"Message":"Index was out of range. Must be non-negative and less than the size of the collection.\r\n
Parameter name: index",
"StackTrace":" at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)\r\n
at etc...",
"ExceptionType":"System.ArgumentOutOfRangeException"
}
Edit: This could be because the function I'm calling is marked with these attributes:
<WebMethod()> _
<ScriptMethod()> _
Should I be throwing the errors in the
ashx, or should I be returning a
status code as part of the data
returned by the call to
userCreation.ashx, then using this to
decide what action to take? How do you
handle these situations?
Personally, if possible, I would prefer to handle this on the server side and work up a message to the user there. This works very well in a scenario where you only want to display a message to the user telling them what happened (validation message, essentially).
However, if you want to perform an action based on what happened on the server, you may want to use a status code and write some javascript to perform various actions based on that status code.
Now I have a problem as to which answer to accept.
Further thought on the problem brings me to the conclusion that I was incorrectly throwing exceptions. Duplicate user names, email addresses etc are expected issues during a sign up process and are therefore not exceptions, but simply errors. In which case I probably shouldn't be throwing exceptions, but returning error codes.
Which leads me to think that irobinson's approach should be the one to take in this case, especially since the form is only a small part of the UI being displayed. I have now implemented this solution and I am returning xml containing a status and an optional message that is to be displayed. I can then use jQuery to parse it and take the appropriate action: -
success: function(data){
var created = $("result", data).attr("success");
if (created == "OK"){
resetNewUserForm();
listUsers('');
} else {
var errorMessage = $("result", data).attr("message");
$("#newUserErrorMessage").text(errorMessage).show();
}
enableNewUserForm();
}
However travis' answer is very detailed and would be perfect during debugging or if I wanted to display an exception message to the user. I am definitely not receiving JSON back, so it is probably down to one of those attributes that travis has listed, as I don't have them in my code.
(I am going to accept irobinson's answer, but upvote travis' answer. It just feels strange to be accepting an answer that doesn't have the most votes.)

Resources