在浏覽器打開開發者工具發現，它的上傳的位址是這樣的
打開一個正常通路的網頁，比較他們的參數
對比兩者發現，他們的不同就在于remote address這裡，第一個是想8003端口發送資料，第二個是往80端口發送資料。經驗證，因為使用的nginx upload module這個插件，上傳的檔案會先從nginx 80端口走到背景tornado 8003端口，但是在背景的tornado 8003端口并沒有收到任何請求資訊。
問題肯定是處在nginx了，去檢視一個nginx的
`cd /var/log/nginx`
`sudo cat error.log`
最近一條錯誤資訊如下
```
2020/05/21 16:30:00 [error] 44356#0: *53 could not find named location "http://127.0.0.1:8003/upload", client: 127.0.0.1, server: 127.0.0.1, request: "POST /upload HTTP/1.1", host: "127.0.0.1", referrer: "http://127.0.0.1/data/upload/"
```
錯誤資訊提示，重點在标紅的資訊，這裡說明我們的所在。經檢視http://127.0.0.1:8003/upload，
通路這個連接配接http://127.0.0.1:8003/upload，确實是可以通路的，并且背景也能看到值，為什麼nginx無法回傳回去呢？
隻能再去看看nginx的配置檔案，經過折騰發現是poss_proxy出現了問題，最終将配置檔案改為：
`````
location /upload{
# Pass altered request body to this location
#upload_pass @test;
#tornado 通路位址
upload_pass @backend;
upload_pass_args on;
# Store files to this directory
# The directory is hashed, subdirectories 0 1 2 3 4 5 6 7 8 9 should exist
#upload_store /tmp 1;
upload_store /tmp/dmomb_tmp;
# Allow uploaded files to be read only by user
upload_store_access user:r;
# Set specified fields in request body
upload_set_form_field $upload_field_name.name "$upload_file_name";
upload_set_form_field $upload_field_name.content_type "$upload_content_type";
upload_set_form_field $upload_field_name.path "$upload_tmp_path";
# Inform backend about hash and size of a file
upload_aggregate_form_field "$upload_field_name.md5" "$upload_file_md5";
upload_aggregate_form_field "$upload_field_name.size" "$upload_file_size";
upload_pass_form_field "^submit$|^description$";
upload_pass_form_field "^.*$";
upload_cleanup 400 404 499 500-505;
}
location @backend {
proxy_pass http://127.0.0.1:8003;
}
`````
然後再運作，後端終于可以收到前端的資料了。