Flask - 上传时的空文件

Question

我有一个项目允许用户上传文件，他们最终会得到处理，然后提供结果文件。

我刚刚意识到，现在我正在尝试实现系统的处理部分，上传时文件是空的，我不确定哪里出了问题。文件已成功命名并放入目录，但为空。

任何帮助将不胜感激。

上传的html表单：

<div class="tile is-vertical is-parent coach" id='fileUploadTile'>
  <div class="tile is-child box has-background-light">

      <form action='/' method='POST' enctype="multipart/form-data">
        <div class='drop-zone'>
          <span class='drop-zone__prompt is-family-monospace'>Drag and drop or click here to upload files</span>

          <input class="drop-zone__input" type="file" multiple name="uploaded_file" id='fileLoader'>

        </div> <!-- end of drop-zone-->
        <div class='buttons are-medium' id='fileButtons'>
          <input type='submit' class="button is-success is-light is-outlined is-family-monospace" id='submitFiles' value='Process file(s)'>
          </form>
          <button class='button is-danger is-light is-outlined is-family-monospace' name='resetFiles' id='resetFiles'>Reset File(s)</button>
        </div> <!-- end of buttons -->
       
    </div> <!-- end of tile is-child -->
   

  </div> <!-- end of tile is-vertical -->

尝试验证文件（检查扩展名、文件大小、名称等）然后保存的代码：

def file_upload():
    if session:
        session_name = session.get('public_user')
        print("New request from " + str(session_name))
        # update when last request was sent
        active_sessions[session_name] = datetime.now()
    else:
        session_token = generate_session_token()
        print("Generating new session... " + session_token)
        session['public_user'] = session_token  # session = key, last request = value
        active_sessions[session_token] = datetime.now()
        os.mkdir('uploads/'+session['public_user']) #create directory for uploaded files

    if request.method == "POST":
        if request.files:
            files_processed = True
            files = request.files.getlist("uploaded_file")
            upload_path = app.config['UPLOAD_FOLDER'] + \
                str(session['public_user'])
            # loop, as possibility of multiple file uploads
            for file_to_upload in files:
                file_to_upload.seek(0, os.SEEK_END)
                file_length = file_to_upload.tell()
                file_name = check_existing_file_name(file_to_upload.filename)
                # Secures file name against user input
                file_name = secure_filename(file_name)
                # Checks the file name isn't blank
                if file_to_upload.filename == "":
                    print("Error with file" + file_to_upload.filename +
                          " - name must not be blank")
                    files_processed = False
                    continue
                # Checks the file has an allowed extension
                elif not allowed_ext(file_to_upload.filename):
                    print("Error with file" + file_to_upload.filename +
                          " - extension not supported")
                    files_processed = False
                    continue
                # Checks file size
                elif file_length > app.config['MAX_FILE_SIZE']:
                    print("Error with file" +
                          file_to_upload.filename + " file too big")
                    files_processed = False
                    continue
                else:  # Else, passes all validation and is saved.
                    file_path = upload_path + "/" + file_name
                    file_to_upload.save(file_path) 
            # If files have been processed, return a render with success message
            if files_processed is True:
                return render_template('index.html', is_home='yes', succ="Now processing your files...")
            else:  # Else, normal redirect.
                return redirect(request.url)
        else:  # If no files request, redirect to index.
            return redirect(request.url)
    else:  # If not a POST request, load page as normal.
        return render_template('index.html', is_home='yes')

对不起，如果这是我错过的简单或愚蠢的事情 - 这是我在 Python 中的第一个项目，也是我第一次使用 Flask。

Answer 1

这一切看起来都不错。

无关：我会针对 file_name 而非 file_to_upload.filename 检查空文件名。

关于您的问题： 唯一明智的答案可能是，通过您的许多操作中的任何一个，您将文件指针放在文件末尾，而 save 无法处理它。

很遗憾，我没有时间在我的电脑上尝试这个，所以请再做一次seek 0 - 这次就在你调用save 方法之前。

我稍后会尝试这个并相应地更新我的答案。

另一种找出发生了什么的方法是使用调试器。这不是太复杂。

我制作了一个 5 分钟的视频 - 仅用于调试 Flask：https://www.youtube.com/watch?v=DB4peJ1Lm2M

Answer 2

我遇到了同样的问题，上面推荐的修复方法帮助了我！据我了解，这是因为当您获取文件大小时，文件指针位于文件末尾。只需使用另一个 file_to_upload.seek(0) 撤消此操作即可。

为了清楚起见，您的代码现在应该如下所示：

file_path = upload_path + "/" + file_name
file_to_upload.seek(0)
file_to_upload.save(file_path)