.NET Image Validation

How it works

1. Upload image to the server.
2. Validate image on the server side before storing it.

Jump to Complete Example

Image Upload

The Server Upload section describes the steps to upload an image to a server. You can validate images when you insert them in the editor, however that only checks the filename and not the mime type. It is advisable to make additional checks on the server side to make sure users only upload valid image formats.

Validate Extension

The editor's .NET SDK can check the image extension before storing it on disk, and can also check the mime type.

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FroalaEditor.ImageOptions options = new FroalaEditor.ImageOptions
{
    Fieldname = "file",
    Validation = new FroalaEditor.ImageValidation(new string[] { "gif", "jpeg", "jpg", "png", "svg", "blob" }, new string[] { "image/gif", "image/jpeg", "image/pjpeg", "image/x-png", "image/png", "image/svg+xml" })
};

object response = FroalaEditor.Image.Upload(System.Web.HttpContext.Current, fileRoute, options);

Custom Validation

You can also pass a custom method instead of validating the extension and mime type. This gives you full control on what types of images you want to store on disk. Below is an example of how to validate if an image is square.

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Func validationFunction = (filePath, mimeType) => {

    MagickImageInfo info = new MagickImageInfo(filePath);

    if (info.Width != info.Height)
    {
        return false;
    }

    return true;
};

FroalaEditor.ImageOptions options = new FroalaEditor.ImageOptions
{
    Fieldname = "file",
    Validation = new FroalaEditor.ImageValidation(validationFunction)
};


var image = new FroalaEditor.Image(System.Web.HttpContext.Current);
object response = image.Upload(fileRoute, options);

Complete Example

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<script>
  new FroalaEditor('.selector', {
    // Set the image upload URL.
    imageUploadURL: '/FroalaApi/UploadImageValidation'
  })
</script>

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using System;
using System.Web.Mvc;

namespace demo.Controllers
{
    public class FroalaApiController : Controller
    {
        public ActionResult UploadImageValidation()
        {
            string fileRoute = "/Public/";

            FroalaEditor.ImageOptions options = new FroalaEditor.ImageOptions
            {
                Fieldname = "file",
                Validation = new FroalaEditor.ImageValidation(new string[] { "gif", "jpeg", "jpg", "png", "svg", "blob" }, new string[] { "image/gif", "image/jpeg", "image/pjpeg", "image/x-png", "image/png", "image/svg+xml" })
            };

            try
            {
                return Json(FroalaEditor.Image.Upload(System.Web.HttpContext.Current, fileRoute, options));
            }
            catch (Exception e)
            {
                return Json(e);
            }
        }
    }
}