network_tools.py

from __future__ import unicode_literals
from ipaddress import ip_address
from json import loads
import socket
import urllib.request
from sys import exit, stderr


def discover_peers(ep, discover):
    """
    From first node, discover his known nodes.
    Remove from know nodes if nodes are down.
    If discover option: scan all network to know all nodes.
        display percentage discovering.
    """
    endpoints = parse_endpoints(get_request(ep, "network/peers")["peers"])
    if discover:
        print("Discovering network")
    for i, ep in enumerate(endpoints):
        if discover:
            print("{0:.0f}%".format(i / len(endpoints) * 100))
        if best_node(ep, 0) is None:
            endpoints.remove(ep)
        elif discover:
            endpoints = recursive_discovering(endpoints, ep)
    return endpoints


def recursive_discovering(endpoints, ep):
    """
    Discover recursively new nodes.
    If new node found add it and try to found new node from his known nodes.
    """
    news = parse_endpoints(get_request(ep, "network/peers")["peers"])
    for new in news:
        if best_node(new, 0) is not None and new not in endpoints:
            endpoints.append(new)
            recursive_discovering(endpoints, new)
    return endpoints


def parse_endpoints(rep):
    """
    endpoints[]{"domain", "ip4", "ip6", "pubkey"}
    list of dictionaries
    reps: raw endpoints
    """
    i, j, endpoints = 0, 0, []
    while (i < len(rep)):
        if (rep[i]["status"] == "UP"):
            while j < len(rep[i]["endpoints"]):
                ep = parse_endpoint(rep[i]["endpoints"][j])
                j += 1
                if ep is None:
                    break
                ep["pubkey"] = rep[i]["pubkey"]
                endpoints.append(ep)
        i += 1
        j = 0
    return endpoints


def parse_endpoint(rep):
    """
    rep: raw endpoint, sep: split endpoint
    domain, ip4 or ip6 could miss on raw endpoint
    """
    ep, sep = {}, rep.split(" ")
    if sep[0] == "BASIC_MERKLED_API":
        if check_port(sep[-1]):
            ep["port"] = sep[-1]
        if len(sep) == 5 and check_ip(sep[1]) == 0 and check_ip(sep[2]) == 4 and check_ip(sep[3]) == 6:
            ep["domain"], ep["ip4"], ep["ip6"] = sep[1], sep[2], sep[3]
        if len(sep) == 4:
            ep = endpoint_type(sep[1], ep)
            ep = endpoint_type(sep[2], ep)
        if len(sep) == 3:
            ep = endpoint_type(sep[1], ep)
        return ep
    else:
        return None


def endpoint_type(sep, ep):
    typ = check_ip(sep)
    if typ == 0:
        ep["domain"] = sep
    elif typ == 4:
        ep["ip4"] = sep
    elif typ == 6:
        ep["ip6"] = sep
    return ep


def check_ip(address):
    try:
        return ip_address(address).version
    except:
        return 0


def get_request(ep, path):
    address = best_node(ep, 0)
    if address is None:
        return address
    url = "http://" + ep[address] + ":" + ep["port"] + "/" + path
    if ep["port"] == "443":
        url = "https://" + ep[address] + "/" + path
    request = urllib.request.Request(url)
    response = urllib.request.urlopen(request)
    encoding = response.info().get_content_charset('utf8')
    return loads(response.read().decode(encoding))


def post_request(ep, path, postdata):
    address = best_node(ep, 0)
    if address is None:
        return address
    url = "http://" + ep[address] + ":" + ep["port"] + "/" + path
    if ep["port"] == "443":
        url = "https://" + ep[address] + "/" + path
    request = urllib.request.Request(url, bytes(postdata, 'utf-8'))
    try:
        response = urllib.request.urlopen(request)
    except urllib.error.URLError as e:
        print(e, file=stderr)
        exit(1)
    encoding = response.info().get_content_charset('utf8')
    return loads(response.read().decode(encoding))


def best_node(ep, main):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    addresses, port = {"ip6", "ip4", "domain"}, int(ep["port"])
    for address in addresses:
        if address in ep:
            try:
                s.connect((ep[address], port))
                s.close()
                return address
            except:
                pass
    if main:
        print("Wrong node given as argument", file=stderr)
        exit(1)
    return None


def check_port(port):
    try:
        port = int(port)
    except:
        print("Port must be an integer", file=stderr)
        exit(1)
    if (port < 0 or port > 65536):
        print("Wrong port number", file=stderr)
        exit(1)
    return 1


def get_current_block(ep):
    return get_request(ep, "blockchain/current")