CODEWITHSUNDEEP
asp.net-mvc-4bundling-and-minificationasp.net-optimization
slolife
slolife

Reputation: 19870

Catching and logging MVC4 message about "Minification failed. Returning unminified contents"

There are a number of questions on StackOverflow that talk about getting the Minification failed. Returning unminified contents error from the MVC4 minification.

I'd like to know if there is a way to be notified about this error when it happens and to be able to log it.

It is nice that when there is an error the bundler returns the original contents so my site doesn't break, but I would like to know about these errors automatically rather than having to visit each css/js bundle url to see if there is an error.

Upvotes: 2

Views: 1082

Answers (1)

Hao Kung
Hao Kung

Reputation: 28200

So that logic is actually in the implementation of the default transforms that Script/StyleBundle are using. If you want to catch those errors yourself, you can change the transforms on your bundles to something that surfaces those errors:

So to actually detect the errors, you would have to manually enumerate all of your bundles (to trigger them to get generated), and also be able to listen to errors that happened (so the GenerateErrorResponse equivalent below would need to report any errors to someplace that you would see)

Here's what JsMinify does in its process for reference:

    /// <summary>
    /// Transforms the bundle contents by applying javascript minification
    /// </summary>
    /// <param name="context">The <see cref="BundleContext"/> object that contains state for both the framework configuration and the HTTP request.</param>
    /// <param name="response">A <see cref="BundleResponse"/> object containing the bundle contents.</param>
    public virtual void Process(BundleContext context, BundleResponse response) {
        if (!context.EnableInstrumentation) {
            Minifier min = new Minifier();
            // NOTE: Eval immediate treatment is needed for WebUIValidation.js to work properly after minification
            // NOTE: CssMinify does not support important comments, so we are going to strip them in JS minification as well
            string minifiedJs = min.MinifyJavaScript(response.Content, new CodeSettings() { EvalTreatment = EvalTreatment.MakeImmediateSafe, PreserveImportantComments = false });
            if (min.ErrorList.Count > 0) {
                GenerateErrorResponse(response, min.ErrorList);
            }
            else {
                response.Content = minifiedJs;
            }
        }

        response.ContentType = JsContentType;
    }

Upvotes: 3

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