Imageprocessor: Issue with query strings on images

[RetoxChris]

Hello,

I've recently bought a software called Flippingbook https://flippingbook.com/ which creates HTML 5 brochures. I have published a magazine and it works fine locally.

However when I upload the magazine to my website, I am getting issues with accessing the files in the magazine and it's causing a server error. The software automaically adds query strings to the images in the magazine. Here is a link to the brochure:

https://www.s.co.uk/brochure-2/index.html

The console errors reveal the images have been set up as:

https://www.s.co.uk/brochure-2/files/assets/common/page-html5-substrates/page0001_2.jpg?uni=b5e7fd95e5123a5801a44906ede1a557

However, when you remove the query string the images show:

https://www.s.co.uk/brochure-2/files/assets/common/page-html5-substrates/page0001_2.jpg

We use the ImageProcessor on our site, and was told by the team at Flipping Book to as for your assistance.

[JimBobSquarePants]

You can use the ImageProcessingModule.ValidatingRequest event to ignore those query strings.

https://imageprocessor.org/imageprocessor-web/imageprocessingmodule/#events

[RetoxChris]

While the original link i posted now works adding the fix you recommend my second link https://www.medburnhomes.co.uk/brochure-2/files/assets/common/page-html5-substrates/page0001_2.jpg?uni=b5e7fd95e5123a5801a44906ede1a557 doesnt. The console suggests a Bad Request and server gives the same error as before. Is there anything else i need to add/configure

[JimBobSquarePants]

Are you seeing arg.Cancel to true? If so, don't. Just chop the parameter off the request. ImageProcessor.Web will then ignore it and the static file handler will take over

[RetoxChris]

Here is my code based on your article and understanding of what you may want me to do.

In debug mode i can see all the values, I try and remove the parameter from the collection but it doesnt make a difference. I set arg.Cancel = false but also noticed it never enters this block

    protected override void OnApplicationStarted(object sender, EventArgs e)
    {
        base.OnApplicationStarted(sender, e);
        ImageProcessingModule.ValidatingRequest += ImageProcessingModule_ValidatingRequest;
    }



    private void ImageProcessingModule_ValidatingRequest(object sender, ImageProcessor.Web.Helpers.ValidatingRequestEventArgs args)
    {
        if (!string.IsNullOrWhiteSpace(args.QueryString))
        {
            var queryCollection = HttpUtility.ParseQueryString(args.QueryString);
            queryCollection.Remove("uni");
            if (queryCollection.AllKeys.Contains("alpha"))
            {
                args.Cancel = false;
                return;
            }



            // If there's a crop parameter, force it to always just be a specific value
            if (queryCollection.AllKeys.Contains("crop"))
            {
                queryCollection["crop"] = "10,10,10,10";



                // This performs the reverse of ParseQueryString since the result of ParseQueryString
                // is actually an instance of System.Web.HttpValueCollection
                args.QueryString = queryCollection.ToString();
            }
        }
    }

Could you confirm what the final code should be?

[ronaldbarendse]

Maybe a better approch would be to completely remove the ImageProcessorModule within the directory contains the static flipbook files?

This can be done by adding the following configuation into brochure-2\Web.config (the httpModules section might be redundant, as that's for very old IIS versions):

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.web>
        <httpModules>
            <remove name="ImageProcessorModule" />
        </httpModules>
    </system.web>
    <system.webServer>
        <modules>
            <remove name="ImageProcessorModule" />
        <modules>
    </system.webServer>
</configuration>

[JimBobSquarePants]

Why have you got all that extra code in your event handler?

You're never updating the args.QueryString value.

[RetoxChris]

Sorry which section are you referring to? I copied the code from the link but can you confirm what you need me to change to so i can test?

[JimBobSquarePants]

The code in the link is a generic example of how the event can be handled. You need to write the code to handle your specific case.

[JimBobSquarePants]

```c#
private void ImageProcessingModule_ValidatingRequest(object sender, ImageProcessor.Web.Helpers.ValidatingRequestEventArgs args)
{
if (!string.IsNullOrWhiteSpace(args.QueryString))
{
// Read
var queryCollection = HttpUtility.ParseQueryString(args.QueryString);

    // Remove
    queryCollection.Remove("uni");

    // Update
    args.QueryString = queryCollection.ToString();
}

}
```

[RetoxChris]

I just now made a change to the original code which is close to what you have posted once i understood that was a boiler template code :-( - looks to be working now though i'll test a few scenarios- Thanks

[JimBobSquarePants]

Hurrah! 🚀 Happy to help. Glad it's working