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fabianwennink / IconCaptcha-ASP.NET

IconCaptcha is a fast, simple and user-friendly captcha. - ASP.NET MVC package
MIT License
15 stars 3 forks source link

[Bug]: Page scaling causes verification to fail #5

Closed Nooreenzentso closed 10 months ago

Nooreenzentso commented 10 months ago

Bug report requirements

IconCaptcha version

latest

ASP.NET version

ASP.NET Core 6.0

Browsers affected

Google Chrome, Microsoft Edge

Expectation

When I select the icon that appears least with my browser's zoom at 67%, I expect the verification to succeed

Actual behaviour

Verification fails, receiving the "UH OH. You've selected the wrong image." message.

Relevant log information

icon-captcha.min.js:2 

       POST http://localhost:5000/iconcaptcha 500 (Internal Server Error)
ajax @ icon-captcha.min.js:2
b @ icon-captcha.min.js:2
(anonymous) @ icon-captcha.min.js:2
setTimeout (async)
click @ icon-captcha.min.js:2

Additional information

While I encounter this issue with IconCaptcha implemented in my own solution, the same behaviour is observed using the demo project from the "3.x develop" branch. This issue also occurs for users with custom scaling on their computers (though I do not have exact scaling settings to share), but is reproduceable when setting the browser zoom to 67%. This occurs specifically when the captcha is loaded with the browser at this zoom; if the browser zoom is at any other setting when the captcha is loaded, then the zoom is changed to 67% and the correct image is selected, the verification is completed successfully.

fabianwennink commented 10 months ago

Hi! Thanks for the report. I'll investigate this further and will inform you once I have an update.

fabianwennink commented 10 months ago

After some investigating, it appears that when setting the browser to 67%, the image width sent to the server for validation is no longer an integer. An integer value (usually a width of 320) is expected, but at this scale, the image width read by JS turns into 319.992. As the server expects an integer and not a float/double, this will thrown an exception. The same issue appears to occurs in the PHP version of IconCaptcha.

I will fix this in the 3x-develop branch so that this no longer occurs once that version is ready.

fabianwennink commented 10 months ago

Hi! I forgot to post a comment last week, but this issue has been resolved in the 3.x-develop branch.