fail muat naik borang borang,

Accept:text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Encoding:gzip, deflate, br
Accept-Language:zh-CN,zh;q=0.8
Cache-Control:max-age=0
Connection:keep-alive
Content-Length:1495
Content-Type:multipart/form-data; boundary=----WebKitFormBoundaryA0iAa0dqm6ZugY1G
Host:127.0.0.1:8899
Origin:http://127.0.0.1:8899
Referer:http://127.0.0.1:8899/file/file.html
Upgrade-Insecure-Requests:1
User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36

Tetapi badan dikodkan data

------WebKitFormBoundaryA0iAa0dqm6ZugY1G
Content-Disposition: form-data; name="file"; filename="2.jpg"
Content-Type: image/jpeg


------WebKitFormBoundaryA0iAa0dqm6ZugY1G
Content-Disposition: form-data; name="submit"

Submit
------WebKitFormBoundaryA0iAa0dqm6ZugY1G--

Panjang Kandungan tidak sepadan dengan panjang badan sebenar, jadi jika saya memuat naik fail besar, seperti 5M, dan saya ingin membaca 1M secara berurutan di sisi pelayan, apakah yang perlu saya lakukan?