Question

我正在使用MangoDB和GridFS来存储图像。我有这条路线从DB中检索图像：

app.get("/images/profile/:uId", function (req, res) {
let uId = req.params.uId;
console.log(uId)
gfs.files.findOne(
  {
    "metadata.owner": uId,
    "metadata.type": 'profile'
  }
  , function (err, file) {
    if (err || !file) {
      return res.status(404).send({ error: 'Image not found' });
    }
    var readstream = gfs.createReadStream({ filename: file.filename });
    readstream.on("error", function (err) {
      res.send("Image not found");
    });
    readstream.pipe(res);
  });
});

这会返回类似的内容：

�PNG


IHDR���]�bKGD���̿   pHYs
�
�B(�xtIME�  -u��~IDATx��i|TU����JDV�fH�0� :-
H_��M��03`���
(��-�q{U[�m�A��AQ�VZ�ҢbP��S�@K@��CB��|��T�[�=����"U��[��{�s�9�  
�+)@eۿ���{�9���,?�T.S��xL֟x&@�0TSFp7���tʁ���A!_����D�h� 
z����od�G���YzV�?e���|�h���@P�,�{�������Z�l\vc�NӲ�?
n��(�r�.......

好像我正确地得到了png。我如何在img标签中显示呢？

Answer 1

我已通过将块转换为base64字符串解决了该问题。然后，我将字符串传递如下：

  const readstream = gfs.createReadStream(file.filename);
  readstream.on('data', (chunk) => {
    res.render('newHandlebarFile', { image: chunk.toString('base64') });
  })

我在车把中渲染值，如下所示：

  <img src="data:image/png;base64,{{ image }}" alt="{{ image }}">

Answer 2

exports.itemimage = function（req，res）{

gfs.files.findOne({ filename: req.params.filename }, (err, file) => {
    res.contentType(file.contentType);
    // Check if image
    if (file) {
      // Read output to browser
      const readstream = gfs.createReadStream(file.filename);
      readstream.pipe(res);
    } else {
        console.log(err);
    }
});

};

Answer 3

我得到了答案您要做的就是在设置路由时，在img src中输入URL

app.get('/image/:filename', (req, res) => {
gfs.files.findOne({ filename: req.params.filename }, (err, file) => {
// Check if file
if (!file || file.length === 0) {
  return res.status(404).json({
    err: 'No file exists'
  });
}

// Check if image
if (file.contentType === 'image/jpeg' || file.contentType === 'image/png') {
  // Read output to browser
  const readstream = gfs.createReadStream(file.filename);
    readstream.pipe(res)
} else {
  res.status(404).json({
    err: 'Not an image'
  });
 }
});
});

而且有效

GridFS：如何在<img/>标记中显示readstream.pipe（res）的结果？

3 个答案: