有时我会得到多部分表单的无效csrf令牌

我正在使用带有csurf和强大的expressjs 4，有时当我使用多部分表单上传时：

错误：在Layer.handle（/ Users / mecha / projects / sherka / maktabi / node_modules /）中createToken（/Users/mecha/projects/sherka/maktabi/node_modules/csurf/index.js:94:19）处的csrf令牌无效csurf / index.js：59：24）在/ Users / mecha / projects / sherka /的trim_prefix（/Users/mecha/projects/sherka/maktabi/node_modules/express/lib/router/index.js:240:15） maktabi / node_modules / express / lib / router / index.js：208：9 at Function.proto.process_params（/Users/mecha/projects/sherka/maktabi/node_modules/express/lib/router/index.js:269:12 ）下一个（/Users/mecha/projects/sherka/maktabi/node_modules/express/lib/router/index.js:199:19）/ Users / mecha / projects / sherka / maktabi / node_modules / express-session / index .js：226：9 at object._onImmediate（/Users/mecha/projects/sherka/maktabi/node_modules/express-session/session/memory.js:58:9）at processImmediate [as _immediateCallback]（timers.js：330 ：15）

但有时它只是工作正常没有任何错误，任何想法是什么，我做错了？

这是我的代码

app.use(function(req, res, next){
    res.locals.session = req.session;
    res.locals.messages = req.flash('success');
    res.locals.errors = req.flash('error');
    res.locals.csrftoken = req.csrfToken();
    next();
});

这是一个HTML表单

<form id="new_desk_form" class="form" method="post" action="/space/{{ space.id}}/add/desk?_csrf={{ csrftoken }}" enctype="multipart/form-data">

这是路由处理程序

app.post('/space/:id/add/desk', helpers.ensureAuth, function(req, res){
    var id = req.params.id;
    var form = new formidable.IncomingForm();
    form.uploadDir = __dirname+'/../public/uploads/spaces/'+id;
    form.keepExtensions = true;
    form.encoding = 'utf-8';
    form.parse(req, function(err, fields, files){
        if(err){
            console.log(err);
            res.render('505.html')
        }
        var name = files.photo1.path.split('/');
        name = name[name.length-1];
        var pathToStore = "/uploads/spaces/"+id+'/'+name;
        var workspace = {};
        workspace.title = req.body.title;
        workspace.type = 'desk';
        workspace.photos = [];
        workspace.photos.push(pathToStore);
        workspace.currency = req.body.currency;
        workspace.quantity = req.body.quantity;
        workspace.prices = {};
        if(req.body.hourly){
            workspace.prices.hourly = req.body.hourly;
        }
        if(req.body.daily){
            workspace.prices.daily = req.body.daily;
        }
        if(req.body.monthly){
            workspace.prices.monthly = req.body.monthly;
        }
        Space.findOne({_id: id}, {}, function(err, space){
            if(err){
                console.log(err);
                    res.render('505.html');
            }
            space.workspaces.push(workspace);
            space.save(function(){
                res.redirect('/edit/'+req.id);
            })
        });
    });
});