When uploading WeChat Mini Programs images, the first upload on iOS is bound to fail. Nignx returns 400, and the upload will be successful again within a short period of time. And Android runs perfectly.

self-analysis:
1 is Mini Program"s own compatibility problem.

2 is an nginx configuration issue.

I have visited Mini Program"s official community and saw that several people have encountered the same questions as me, but none of them have been answered in detail. I also described my problems in detail.
https://developers.weixin.qq.

it is possible that the problem that client_header_buffer_size or large_client_header_buffers is not big enough is returned after searching nginx on the Internet, and it has also been adjusted. They are 128k and 1m respectively. But the problem remains.

it doesn"t feel like a buffer size problem, because the Android side (the machine I can find) runs perfectly, while the iOS side (the machine I can find) must fail for the first time, and then upload it again in a short period of time. But it will fail again in a few minutes. It"s really weird.

what is even more amazing is that I want to grab packets through fildder. But there"s no way to reproduce the problem. Once the phone is connected to the agent, it will be uploaded successfully. The same problem occurs when you disconnect the agent and use the 4G network.

attach log of nginx
failed log
xxx.xxx-- [05/Jun/2018:14:27:57 + 0800] "POST / api/seek/imgUpload HTTP/2.0" 400220 "https://servicewechat.com/wx02bbc36d9065ad9e/0/page-frame.html"" Mozilla/5.0 (iPhone; CPU iPhone OS 11 million 2 like Mac OS X) AppleWebKit/604.3.5 (KHTML, like Gecko) Mobile/15B202 MicroMessenger/6.6.1 NetType/WIFI Language/zh_CN "

successful log
xxx.xxx--[05/Jun/2018:14:28:04 + 0800] "POST / api/seek/imgUpload HTTP/2.0" 200238 "https://servicewechat.com/wx02bbc36d9065ad9e/0/page-frame.html"" Mozilla/5.0 (iPhone; CPU iPhone OS 1131 like Mac OS X) AppleWebKit/604.3.5 (KHTML, like Gecko) Mobile/15B202 MicroMessenger/6.6.1 NetType/WIFI Language/zh_CN "

I can"t see the difference. No, no, no. Exactly the same

the above is my complete description and the solution I have tried. None of it has been solved.

I appreciate the trouble that all the gods take the time to help. No, no, no.