从节点JavaScript返回到jQuery的Ajax调用落在错误函数上

Question

I have jQuery as client script and node JavaScript server as back-end.

I used to post the request to node server for getting data. Please find my AJAX call below.

My problem is even if my response is set to success it always comes in error function of the jquery.AJAX method.

And error object looks like

$.ajax({
        url : 'http://127.0.0.1:3000/uploadcontent/fileUpload',
        type : 'post',
        data : formData,
        enctype : 'multipart/form-data',
        processData : false,
        contentType : false,
        error : function(error,jqXHR, exception) {
            errorMessage(error);
            console.log(JSON.stringify(error))
            console.log(exception +"  :  "+error);
        },
        success : function(data) {
            alert(data);
            if (data.sucess){
                successMessage(data.returnMessage);
            } else {
                alert('error');
                if (data.returnObj != null) {

                } else{
                    errorMessage(data.returnMessage);
                }
            }
        }
    })

Now, find below my node JavaScript route for the above request.

app.post('/fileupload', function(req, res) {

    var fstream;
    var fileName, bunchId, standard, userKey, subject, unit, chapter, topic;
    req.pipe(req.busboy,function(err) {
        if(err) {
            console.log("ERROR: " + err.code + " (" + err.message + ")");
            return;
        }
    });
    req.busboy.on('file', function (fieldname, file, filename) {
        console.log("Uploading: " + filename);          
        fstream = fs.createWriteStream(config.content_upload_path.pdf_path + filename + 'abc');         
        file.pipe(fstream,function(err) {
            if(err) {
                console.log('pipe error due to stream')
                console.log("ERROR: " + err.code + " (" + err.message + ")");
                return;
            }
        });
        fstream.on('close', function () {
            fileName = filename;
            fileObject = file;       
            uploadFile(paramData, res)
            res.redirect('back');
            console.log('method complete')
        });

        fstream.on('error', function (err) {
            console.log('stream on error event')
            console.log(err)
            generateWebServiceResponse(res, false, null, 200, err)
            console.log(res);
            res.send()              
        });

    });}

generateWebServiceResponse method looks like this:

function generateWebServiceResponse(response, isSuccess, result, httpStatus,
    returnMessage) {
response.json({
    isSucess : isSuccess,
    returnObj : result,
    returnMessage : returnMessage,
    resultCode : 0,
    httpStatus : httpStatus
});}

Even in case of failure it should land in success function with isSuccess = false . But in each case it is landed in error case.

I am also not able to solve access origin error mentioned in the attached image.

Answer 1

It happened because of CORS . You must enable CORS for your route. The simplest way is using Node.js CORS middleware