寫完後，nodejs gridFS寫入流錯誤

Question

使用下面的代碼，我可以上傳一個圖像到mogodb一次，如果我再試一次，我得到一個錯誤。

我做了一些研究，其因爲writestream正在關閉NODEJS writeStream error

conn.once('open', function() { 

    var gfs = Grid(conn.db, mongoose.mongo); 

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

     form.on('part', function(part){ 
      if(!part.filename) return; 
      size = part.byteCount; 
      fileName = part.filename; 
     }); 

     form.on('file', function(name,file){ 

      var tempfile = file.path; 
      var origname = fileName; 

      var writestream = gfs.createWriteStream({ filename: origname }); 

      fs.createReadStream(tempfile).on('end', function() { 
       res.send('<p><h1>Upload Complete!</h1><p>'); 
      }).on('error', function() { 
       res.send('Error, upload failed!'); 
      }).pipe(writestream); 

     }); 

     form.parse(req); 

    }); 


    app.get('/image/:id', function(req,res){ 

     console.log(req.params.id) 
     gfs.createReadStream({_id:req.params.id}).pipe(res); 

    }); 

}); 

錯誤消息看起來像這樣

events.js:72 
     throw er; // Unhandled 'error' event 
      ^
Error: write after end 
    at writeAfterEnd (C:\Users\Michael\Desktop\Chat-App\node_modules\multiparty\node_modules\readable-stream\lib\_stream_writable.js:161:12) 
    at Form.Writable.write (C:\Users\Michael\Desktop\Chat-App\node_modules\multiparty\node_modules\readable-stream\lib\_stream_writable.js:208:5) 
    at write (_stream_readable.js:582:24) 
    at flow (_stream_readable.js:591:7) 
    at _stream_readable.js:559:7 
    at process._tickCallback (node.js:419:13) 

所以看起來多方是我的代碼有問題。我的問題是我應該如何解決這個問題，我應該改變我的post方法來運行代碼上的代碼？

Answer 1

更換

var form = new multiparty.Form(); 

內

app.post('/upload', function(req,res){...}); 

不申報var form全球。它應該初始化每個帖子請求