HTML 5定位标记下载的文件不完整？

Question

I am using angular and ASP.NET Web API to allow users to download files that are generated on the server.

HTML Markup for download link:

 <img src="/content/images/table_excel.png">
 <a ng-click="exportToExcel(report.Id)">Excel Model</a>
 <a id="report_{{report.Id}}" target="_self"></a>

The last anchor tag is there to serve as a place holder for an automatic click event. The visible anchor calls the exportToExcel method to initiate the call to the server and begin creating the file.

$scope.exportToExcel = function(reportId) {
    reportService.excelExport(reportId, function (result) {
        var url = "/files/report_" + reportId + "/" + result.data.Model.fileName;
        var dLink = document.getElementById("report_" + reportId);
        dLink.href = url;
        dLink.setAttribute('download', result.data.Model.fileName);
        dLink.click();
    });
}

The Web API code creates an Excel file. The file, on the server is about 279k, but when it is downloaded on the client it is only 7k. My first thought was that the automatic click might be happening before the file is completely written. So, I added a 10 second $timeout around the click event as a test. It failed with the same result.

This seems to only be happening on our remote QA server. On my local development server I always get the entire file back. I am at a loss as to why this might be happening. We have similar functionality where files are constructed from a database blob and saved to the local disk for download. The same method is employed for the client side download and that seems to work fine. I am wondering if anyone else has run into a similar issue.

Update After the comment by SilentTremmor we think it actually may be IIS or some sort of Sever issue. Originally, we didn't think it could be, but after some digging it may be. It seems the instance of the client code is only allowing 7k of data to be downloaded. It doesn't matter what we try to download the result is always the same.

Answer 1

It turns out the API application was writing the file to a different instance of our application. The client code had no idea and was trying to download a file that did not exist. So, when the download link was creating the file it was empty, thus the small file size.