无法在MVC操作方法上从base64string创建图像

Question

I'm trying to upload image in MVC controller by its content.

$scope.imageUpload = function (event) {
        var files = event.target.files; //FileList object
        fileString = event.target.files[0];
        for (var i = 0; i < files.length; i++) {
            var file = files[i];
            var reader = new FileReader();
            reader.onload = $scope.imageIsLoaded;
            reader.readAsDataURL(file);
        }
    }
    $scope.imageIsLoaded = function (e) {
        $scope.$apply(function () {
            $scope.userProfilePic = e.target.result;
            $.ajax({
                url: "FileUploadWithAjax",
                type: "POST",
                data: 'imageString=' + e.target.result.split(',')[1],
                processData: false
            });
        });
    }

Once the image is loaded, I'm sending its content to MVC controller.

[System.Web.Mvc.HttpPost]
        public void FileUploadWithAjax([FromBody]string imageString)
        {
           bytes = Convert.FromBase64String(imageString);
            using (MemoryStream ms = new MemoryStream(bytes))
            {
                Image image = Image.FromStream(ms);
                image.Save("myBlargyImage.jpg");
            }
        }

But it's breaking while creating image from stream. It throws an error called "Invalid parameter".

An exception of type 'System.ArgumentException' occurred in System.Drawing.dll but was not handled in user code

Additional information: Parameter is not valid.

Stack Trace

at System.Drawing.Image.FromStream(Stream stream, Boolean useEmbeddedColorManagement, Boolean validateImageData) at System.Drawing.Image.FromStream(Stream stream) at Micraft.BBraun.Controllers.EmployeeController.FileUploadWithAjax(String imageString) in D:\\B Braun\\mvc 31 JAN 2017\\Micraft.BBraun\\Controllers\\EmployeeController.cs:line 351 at lambda_method(Closure , ControllerBase , Object[] ) at System.Web.Mvc.ActionMethodDispatcher.<>c__DisplayClass1.b__0(ControllerBase controller, Object[] parameters) at System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary 2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary 2 parameters) at System.Web.Mvc.Async.AsyncControllerActionInvoker.b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult 2.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase 1.End() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.b__3d() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.b__3f()

UPDATE

I was just checking online tool which can generate image from base64string like http://codebeautify.org/base64-to-image-converter

When I copied image text from its source in html, I was able to generate Image on above site.

After that I tried to copy image content which I was getting on my server side method and surprisingly I was not able to generate image.

Then I compared both texts and found some diferences

If you check bellow image carefully, I can see some changes like wherever there's any "+" sign in Image content, its replaced with "blank space".

is there any content type I'm missing that I should use while posting this data to server?

Answer 1

You need to use encodeURIComponent() on the data sent to server. So, in your ajax request, do as follows:

data: 'imageString=' + encodeURIComponent(e.target.result.split(',')[1]),

See AJAX POST and Plus Sign ( + ) -- How to Encode?