Question

我正在尝试使用以flask为后端的dropzone js。 Dropzone配置：

<form method="POST" action='/process_chunk' class="dropzone dz-clickable"
     id="dropper" enctype="multipart/form-data">
</form>

<script type="application/javascript">
   Dropzone.options.dropper = {
       {# https://gitlab.com/meno/dropzone/wikis/faq#chunked-uploads #}
       paramName: 'file',
       acceptedFiles: '.csv',
       chunking: true,
       forceChunking: true,
       chunkSize: 100000, // bytes
       parallelChunkUploads: true,
       maxFilesize: 1025, // megabytes
</script>

和我的烧瓶后端如下

@app.route('/process_chunk', methods=['POST'])
def process_chunk():
    current_chunk = int(request.form['dzchunkindex'])

    file = request.files['file']
    save_path = os.path.join(app.config['DATA_DIR'], file.filename)

    try:
        with open(save_path, 'ab+') as f:
            # Goto the offset, aka after the chunks we already wrote
            f.seek(int(request.form['dzchunkbyteoffset']))
            f.write(file.stream.read())
    except OSError:
        # log.exception will include the traceback so we can see what's wrong
        log.exception('Could not write to file')
        return make_response(("Couldn't write the file to disk", 500))

    total_chunks = int(request.form['dztotalchunkcount'])

    if current_chunk + 1 == total_chunks:
        # This was the last chunk, the file should be complete and the size we expect
        if os.path.getsize(save_path) != int(request.form['dztotalfilesize']):
            log.error(f"File {file.filename} was completed, "
                      f"but has a size mismatch."
                      f"Was {os.path.getsize(save_path)} but we"
                      f" expected {request.form['dztotalfilesize']} ")
            return make_response(('Size mismatch', 500))
        else:
            log.info(f'File {file.filename} has been uploaded successfully')
    else:
        log.debug(f'Chunk {current_chunk + 1} of {total_chunks} '
                  f'for file {file.filename} complete')

    return make_response(("Chunk upload successful", 200))

如果我将parallelChunkUploads设置为false，则可以正常工作。大块一个接一个地上传，生成的文件看起来还可以。例如，我使用的是小文件（409字节），并将块大小设置为50字节：

。

结果文件看起来与输入文件完全一样。当我将parallelChunkUploads设置为true时，并行上传块：

但结果文件完全混乱：

原始文件

cod,char,xx
01,aaaa,xx
02,bbbb,xx
03,cccc,xx
04,dddd,xx
05,eeee,xx
06,ffff,xx
07,gggg,xx
08,iiii,xx
09,kkkk,xx
10,llll,xx
11,mmmm,xx
12,gerf,xx
13,flrg,xx
14,erge,xx
15,lkro,xx
16,ergf,xx
17,kiwu,xx
18,erjg,xx
19,hytj,xx
20,utkj,xx
21,rger,xx
22,ehth,xx
23,kmik,xx
24,ergb,xx
25,ergk,xx
26,egeg,xx
27,ejer,xx
28,gtrh,xx
29,thrh,xx
30,rhtr,xx
31,gtrh,xx
32,thrh,xx
33,rhtr,xx

上传的文件

cod,char,xx
01,aaaa,xx
02,bbbb,xx
03,cccc,xx
0iiii,xx
09,kkkk,xx
10,llll,xx
11,mmmm,xx
12,gerf,xx
13,flrg,xx
14,erge,xx
15,lkro,xx
16,ergf4,dddd,xx
05,eeee,xx
06,ffff,xx
07,gggg,xx
08,x
21,rger,xx
22,ehth,xx
23,kmik,xx
24,ergb,xx
,xx
17,kiwu,xx
18,erjg,xx
19,hytj,xx
20,utkj,x9,thrh,xx
30,rhtr,xx
31,gtrh,xx
32,thrh,xx
33,rhtr,xx

25,ergk,xx
26,egeg,xx
27,ejer,xx
28,gtrh,xx
2

最后一块是红色的，因为前端得到了'Size mismatch', 500的响应，因为上传最后一块之后的文件大小是不同的。你们都知道如何解决吗？

带Flask的Dropzone JS：分块并行上传

0 个答案: