JavaScript code to display PDF file in browser from byte array (not base64 encoded)

Question

I am working with an ASP .NET Web API where the POST function of the API is returning a byte array like so in the C# code:

return Ok(outputStream.ToArray());

Where outputStream is of type System.IO.MemoryStream and the ToArray() is returning a byte array.

This function is returning a PDF stream that I want to display to the users in their browser or at least let them save it.

I've ran across a JavaScript example from Stack Overflow that shows how to get a Blob from a Base64 encoded string and display it and I was able to get it working when the API returned a Base64 encoded string; however, I wasn't able to get it working when the API was return the byte array as shown before.

May I get some code examples of how to get it working when the API is returning a byte array?

Answer 1

My JQuery Ajax POST request looks like:

function LoadPDF() {
        var args = [];
        var x = $.ajax({
            type: "POST",
            url: "DirectoryQuery.aspx/GetFullPdf",
            contentType: "application/json; charset=UTF-8",
            responseType: "text/plain; charset=UTF-8",
            async: true,
            dataType: "json",                             
            processData: "false",
            success: OnSuccess,
            error: OnErrorCall
        }); 
        function OnSuccess(response) {
            var byteArray = new Uint8Array(response.d);

            saveTextAsFile("document.pdf", byteArray);
        }
        function OnErrorCall(response) {
            console.log(response);                
            //location.reload();
        }
    }

Try file-save-as.js, like this:

function saveTextAsFile(fileNameToSaveAs, textToWrite) {
    /* Saves a text string as a blob file*/
    var ie = navigator.userAgent.match(/MSIE\s([\d.]+)/),
      ie11 = navigator.userAgent.match(/Trident\/7.0/) && navigator.userAgent.match(/rv:11/),
      ieEDGE = navigator.userAgent.match(/Edge/g),
      ieVer = (ie ? ie[1] : (ie11 ? 11 : (ieEDGE ? 12 : -1)));

    if (ie && ieVer < 10) {
        console.log("No blobs on IE ver<10");
        return;
    }

    var textFileAsBlob = new Blob([textToWrite], {
        type: 'text/plain'
    });

    if (ieVer > -1) {
        window.navigator.msSaveBlob(textFileAsBlob, fileNameToSaveAs);

    } else {
        var downloadLink = document.createElement("a");
        downloadLink.download = fileNameToSaveAs;
        downloadLink.href = window.URL.createObjectURL(textFileAsBlob);
        downloadLink.onclick = function (e) { document.body.removeChild(e.target); };
        downloadLink.style.display = "none";
        document.body.appendChild(downloadLink);
        downloadLink.click();
    }
}