This scripts is almost as broken as VMWare's download site. Except that it works.

vmware-esxi-dl.py

#!/usr/bin/env python3

import requests
import sys
import re
import urllib
import os
import logging
from os.path import basename
from bs4 import BeautifulSoup

# This file is in the public domain.
# Maciej Grela <enki@fsck.pl>
#
# This scripts is almost as broken as VMWare's download site.
# Except that it works.
#
# Usage: vmware-esxi-dl.py <vmware_login> <vmware_password>
#
# Some notes:
# 0. Double check the account login and password you are using!
# I wasted almost 1h of debugging only to discover that I was
# using an old password.
#
# 1. You need to be registered for the free-esxi6 product and
# accept the EULA. This script cannot do this for you. To check
# if you are registered please go to:
# https://my.vmware.com/en/group/vmware/evalcenter?p=free-esxi6,
# select the "License and Download" panel and see if you have a
# "License Information" and "Download Packages" sections there.
# If you do you are good to go. If instead you only have a
# "Register" button you need to click it and accept the EULA.
# If it's something different then your account is borked.
#
# 2. You can't have a another session open in the browser.
# This will cause problems. If the script doesn't work and
# you're getting messages like:
# CRITICAL:vmware-esxi-dl.py:License page not found and no Register button,
# something stinks. Please try to login usign the browser, log
# out and try again. In case this doesn't help, check the file called
# 'dump.html' in the current directory. It will contain the website HTML
# from the point where the script failed. Examine it in a browser to
# try and figure out what went wrong.

logging.basicConfig(level=logging.INFO)
log = logging.getLogger(__file__)

session = requests.Session()

identity = sys.argv[1]
secret = sys.argv[2]

session.get("https://my.vmware.com/web/vmware/login")

session.post('https://my.vmware.com/oam/server/auth_cred_submit',
             data={'vmware': 'login',
                   'username': identity,
                   'password': secret})

page = BeautifulSoup(session.get(
    "https://my.vmware.com/en/group/vmware/evalcenter?p=free-esxi6").content,
    "lxml")

license_name = "VMware vSphere Hypervisor 6 License"
# Check if we have to register for this product
if not page.find("td", string=re.compile(license_name)):
    log.warn("No license found, checking for register button")
    register_btn = page.find("input", id="button-download-license-register")
    if register_btn is None:
        log.fatal("License page not found and no Register button")
        open("dump.html", "w").write(str(page))
        sys.exit(1)

    log.error("You need to register and accept the EULA")


license_key = page.find(
    "td",
    string=re.compile(license_name)
).parent.find_all("td")[1].get_text()

description = page.find(
    "div",
    class_="binary-description"
).get_text(strip=True)

md5 = re.search('([a-f0-9]{32})', description).group(1)
sha1 = re.search('([a-f0-9]{40})', description).group(1)
sha256 = re.search('([a-f0-9]{64})', description).group(1)

log.info("Expected MD5='%s' SHA1='%s' SHA256='%s'" % (md5, sha1, sha256))

dl_js = page.find("div", class_="downloadManager").find("button")['onclick']
dl_url = re.search(
    re.compile('doDownloadAction\([\'"](.+)[\'"]\)'), dl_js
).group(1)

real_dl_url = session.get(dl_url).json()['popupurl']

filename = basename(urllib.parse.urlparse(real_dl_url).path)

# Store license key and metadata
with open(filename + ".key", 'w') as fd:
    fd.write("%s\n" % (license_key))

with open(filename + ".checksum", 'w') as fd:
    fd.write("MD5 (%s) = %s\n" % (filename, md5))
    fd.write("SHA1 (%s) = %s\n" % (filename, sha1))
    fd.write("SHA256 (%s) = %s\n" % (filename, sha256))

log.info("Downloading image to '%s'" % (filename))

file_content = session.get(real_dl_url, stream=True)

with open(filename, 'wb') as fd:
    for chunk in file_content.iter_content(chunk_size=256*1024):
        sys.stdout.write('+')
        sys.stdout.flush()
        fd.write(chunk)