When I try to upload a file with Flask rest API I get: upstream prematurely closed connection while reading response header from upstream, client - python-3.x

Question

I've been experiencing some issues when I try to upload a file trough my web api using python and flask, so whenever I try to do so I get the following error message (it happens with any kind of file and regardless the size):
2019/12/18 16:30:04 [error] 111206#111206: *12251 upstream prematurely closed connection while reading response header from upstream,
client: xxx.61.xxx.70, server: *mydomain.com*, request: "POST /upload HTTP/1.1", upstream: "uwsgi://unix:/home/climpia/tracking/tracking.sock:", host: "*api.mydomain.com*", referrer: "https://client.mydomain.com/?id_ruta=14130"
Connection reset by xxx.251.xx.158 port 22
I am not sure where is the issue since I have already modded some options on the uWSGI.ini and the nginex.config files, but I still get the same error message. I have checked the code (I am using python and flask) and it seems fine.
This is the uWSGI.ini:
[uwsgi]
module = wsgi
master = true
processes = 5
socket-timeout = 65
http-keepalive = 256
socket = tracking.sock
chmod-socket = 660
vacuum = true
#location of log files
logto = /tmp/%n.log
die-on-term = true
This is the nginex.config file for this project:
server {
server_name mydomain.com api.mydomain.com;
location / {
include uwsgi_params;
uwsgi_pass unix:/home/user/tracking/tracking.sock;
}
listen 443 ssl; # managed by Certbot
ssl_certificate /etc/letsencrypt/live/mydomain.com-0001/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/mydomain.com-0001/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
sendfile on;
client_max_body_size 512M;
keepalive_timeout 0;
}
server {
if ($host = api.mydomain.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
if ($host = mydomain.com) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80;
server_name mydomain.com api.mydomain.com;
return 404; # managed by Certbot
}
This is the python code:
# tracking.py
from flask import Flask, request, session, g, redirect, \
url_for, abort, render_template, flash, jsonify, \
make_response, send_from_directory
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text
from flask_cors import CORS
from datetime import datetime
from werkzeug.utils import secure_filename
import os
app = Flask(__name__, static_folder='static')
app.config.from_object(__name__)
cors = CORS(app, resources={r"/*": {"origins": "https://client.mydomain.com"}})
#cors = CORS(app, resources={r"/*": {"origins": "*"}})
app.config.from_envvar('APP_CONFIG_FILE', silent=True)
DB_URL = 'postgresql+psycopg2://user:pwsd#127.0.0.1/NAME DB'
UPLOAD_FOLDER = 'static/upload'
ALLOWED_EXTENSIONS = {'qpj', 'cpg', 'prj', 'dbf', 'shx', 'shp', 'txt', 'json'}
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 0
app.config['SQLALCHEMY_DATABASE_URI'] = DB_URL
#app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False # silence the deprecation warning
#app.config['SQLALCHEMY_ECHO'] = True
app.config['DEBUG'] = True
db = SQLAlchemy(app)
#app.route('/upload',methods = ['POST'])
def upload_file():
response_object = {'status': 'no se ha cargado nada'}
if request.method =='POST':
if 'flecheo' not in request.files:
print('no viene el FLECHEO')
files = request.files['flecheo']
for f in files:
print(f.filename)
filename = secure_filename(f.filename)
app.logger.info('FileName: ' + filename)
f.save(os.path.join(app.config['UPLOAD_FOLDER'], f.filename))
response_object['message'] = 'Subieron los archivos del shape file'
return jsonify(response_object)
This is the Json:
function uploadFiles(){
var capa = document.getElementsByName('capa');
var flecheo = document.getElementById('getFiles').files;
formData = new FormData();
for(i = 0; i < capa.length; i++) {
if(capa[i].checked)
formData.append('capa', capa[i].value);
}
for(i=0; i < flecheo.length; i++){
console.log(flecheo[i]);
formData.append('flecheo', flecheo[i]);
}
for (var key of formData.entries()) {
console.log(key[0] + ', ' + key[1]);
}
var contentType = {
headers: {
'content-type': 'multipart/form-data'
}
};
axios.post('https://api.mydomain.com/upload', formData, contentType)
.then(response => {
console.log(response);
}).catch(error => {
console.log(error);
});
}
Any help is very much appreciated!