import datetime
from requests import get
from requests.exceptions import ConnectionError, Timeout
from sqlalchemy.exc import IntegrityError
from sqlalchemy.orm.session import Session
from .orm import db
class Node(db.Model):
"""This object contains node information you know."""
#: URL of node
url = db.Column(db.String, primary_key=True)
#: last connected datetime of the node
last_connected_at = db.Column(db.DateTime, nullable=False, index=True)
get_nodes_endpoint = '/nodes'
get_blocks_endpoint = '/blocks'
@classmethod
def get(cls, url: str, session: Session=db.session):
get_node = Node.query.filter_by(url=url).first
node = get_node()
if node:
return node
elif get(f'{url}/ping').text == 'pong':
node = Node(url=url, last_connected_at=datetime.datetime.utcnow())
if session:
session.add(node)
try:
session.commit()
except IntegrityError:
node = get_node()
if node is None:
raise
return node
return node
else:
return None
@classmethod
def update(cls, node: 'Node'):
"""
Update recent node list by scrapping other nodes' information.
"""
try:
response = get(f"{node.url}{Node.get_nodes_endpoint}")
except (ConnectionError, Timeout):
return
for url in response.json()['nodes']:
try:
Node.get(url)
except (ConnectionError, Timeout):
continue
db.session.commit()
def ping(self):
try:
result = get(f'{self.url}/ping').text == 'pong'
if result:
self.last_connected_at = datetime.datetime.utcnow()
return result
except (ConnectionError, Timeout):
return False
