MongoDB:存储的base64缓冲区数据与检索的base64不匹配

Question

我使用Mongoose将小尺寸的base64编码图像（每个大约100-200k)直接发布到mongodb中。在存储之前，我可以看到内容与从客户端发送的内容相同。但是查询的base64字符串和输入的不一样？你知道我错过了什么吗？

    // process the add image request
app.post('/addimage', function(req, res) {
    console.log("Addimage post....");
    var qry = {'_email' : req.user.local.email, 'date' : req.body.date, 'subject' : req.body.subject };
    Item.findOne(qry, function(err, item) {
         if (err) {
             console.log('Find images failed: ' + err);
             var resp = '{"result" : "failed", "msg" : ' + err + ', "_req" : "addimage"}';
             res.send(resp);
         } else {
             if (item == null) { // item doesn't exist, create now
                 var item = new Item();
                 item._email = req.body._email;
                 item.date = req.body.date;
                 item.subject = req.body.subject;
             }

             // add image
             var image = new Image();
             image.timestamp = req.body.timestamp;
             image.contentType = req.body.contentType;
             var imgBuf = new Buffer(req.body.image, 'base64');
             image.image = imgBuf;
             item.images.push(image);

             item.save(function(err, result) {
                 if (err) {
                     console.log('Find images failed: ' + err);
                     var resp = '{"result" : "failed", "msg" : ' + err + ', "_req" : "addimage"}';
                     res.send(resp);
                 } else {
                     res.send('{"result" : "ok", _req: "addimage"}');
                     console.log("Image saved and responded to ...");
                 }
             });
         }
    });
});

存储在req.body.image中的数据字符串以“/9j/4AAQSKZJ...”开头，但从mongo shell中我看到了不同。是Bindata的子类型0造成的吗？

> db.items.find({subject:"Science"},{'images.image':1})

var imageSchema = new mongoose.Schema({
    timestamp   : String,
    contentType : String,
    image       : Buffer,
}, { strict: true });
imageSchema.index({ timestamp: 1}, { unique: true });

var itemSchema = new mongoose.Schema({
_email     : {
                type: String,
                required: true,
            },
date       : {
                type: String,
                required: true,
            },
subject    : {   
                type: String,
                required: true,
            },   
images     : [imageSchema],
}, { strict: false });
itemSchema.index({ _email: 1, date: 1, subject: 1}, { unique: true });

谢了！

Answer 1

它是节点版本；（恢复到0.10.33解决了这个问题！