File size: 6,784 Bytes
f0403fa | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 | #!/usr/bin/env python3
"""Paralelo: baixa um link publico de PASTA do mega.nz.
megadl e sequencial (~0,6 MB/s aqui). Varias conexoes contornam o throttle
por-conexao do Mega. Pula arquivos ja completos (compara tamanho).
"""
from __future__ import annotations
import argparse, base64, json, os, struct, sys, threading, time, urllib.request
from concurrent.futures import ThreadPoolExecutor
from Crypto.Cipher import AES
from Crypto.Util import Counter
API = "https://g.api.mega.co.nz/cs"
_seq = [0]
_lock = threading.Lock()
def b64d(s: str) -> bytes:
s += "=" * (-len(s) % 4)
return base64.b64decode(s.replace("-", "+").replace("_", "/"))
def api(payload, folder_id, tries=6):
for attempt in range(tries):
with _lock:
_seq[0] += 1
sid = _seq[0]
req = urllib.request.Request(
f"{API}?id={sid}&n={folder_id}",
data=json.dumps(payload).encode(),
headers={"Content-Type": "application/json"},
)
try:
out = json.loads(urllib.request.urlopen(req, timeout=90).read())
except Exception:
time.sleep(2 * (attempt + 1)); continue
# Um inteiro negativo no lugar do objeto e um erro do Mega (-3 = tente de novo).
if isinstance(out, int):
out = [out]
if isinstance(out[0], int):
if out[0] in (-3, -4):
time.sleep(3 * (attempt + 1)); continue
raise RuntimeError(f"Mega API error {out[0]}")
return out
raise RuntimeError("Mega API: falhou apos varias tentativas")
def node_keys(k_field: str, master: bytes):
"""O campo `k` pode trazer varias entradas `handle:chave` separadas por `/`
(a pasta e compartilhada por mais de um no). So uma decifra com a master key
do link, entao devolvemos todas as candidatas e quem chama escolhe a que
produz um atributo valido."""
ecb = AES.new(master, AES.MODE_ECB)
out = []
for entry in k_field.split("/"):
if ":" not in entry:
continue
enc = b64d(entry.split(":", 1)[1])
if len(enc) < 16:
continue
out.append(ecb.decrypt(enc[: len(enc) // 16 * 16]))
return out
def node_key(k_field: str, master: bytes) -> bytes:
keys = node_keys(k_field, master)
if not keys:
raise ValueError("no key entry")
return keys[0]
def file_key(nk: bytes):
w = struct.unpack(">8I", nk[:32])
key = struct.pack(">4I", w[0] ^ w[4], w[1] ^ w[5], w[2] ^ w[6], w[3] ^ w[7])
iv = struct.pack(">2I", w[4], w[5]) # 8 bytes de nonce
return key, iv
def attr_name(attr_b64: str, key: bytes) -> str | None:
raw = b64d(attr_b64)
dec = AES.new(key, AES.MODE_CBC, b"\0" * 16).decrypt(raw[: len(raw) // 16 * 16])
dec = dec.rstrip(b"\0")
if not dec.startswith(b"MEGA"):
return None
try:
return json.loads(dec[4:].decode("utf-8", "replace")).get("n")
except Exception:
return None
def download(node, dest_root, folder_id, master, state):
handle, key, iv, size, relpath = node
out = os.path.join(dest_root, relpath)
if os.path.exists(out) and os.path.getsize(out) == size:
with _lock:
state["skipped"] += 1
return
os.makedirs(os.path.dirname(out), exist_ok=True)
tmp = out + ".part"
url = api([{"a": "g", "g": 1, "n": handle}], folder_id)[0]["g"]
ctr = Counter.new(128, initial_value=int.from_bytes(iv + b"\0" * 8, "big"))
aes = AES.new(key, AES.MODE_CTR, counter=ctr)
with urllib.request.urlopen(url, timeout=180) as r, open(tmp, "wb") as f:
while True:
chunk = r.read(1 << 20)
if not chunk:
break
f.write(aes.decrypt(chunk))
with _lock:
state["bytes"] += len(chunk)
os.replace(tmp, out)
with _lock:
state["done"] += 1
def main():
ap = argparse.ArgumentParser()
ap.add_argument("link")
ap.add_argument("--dest", required=True)
ap.add_argument("--workers", type=int, default=12)
a = ap.parse_args()
folder_id, key_b64 = a.link.split("/folder/")[1].split("#")
master = b64d(key_b64)
nodes = api([{"a": "f", "c": 1, "r": 1, "ca": 1}], folder_id)[0]["f"]
names, parents = {}, {}
for n in nodes:
parents[n["h"]] = n.get("p")
if n["t"] == 1:
names[n["h"]] = next(
(nm for nk in node_keys(n["k"], master)
if (nm := attr_name(n["a"], nk[:16]))), n["h"])
# Handle da pasta raiz do link: seu nome nao entra no caminho local
# (megadl tambem o omite; manter igual permite retomar o que ele ja baixou).
roots = {h for h in names if parents.get(h) not in names}
def relpath_of(h):
parts = []
while h in names and h not in roots:
parts.append(names[h]); h = parents.get(h)
return os.path.join(*reversed(parts)) if parts else ""
jobs, undecodable = [], []
for n in nodes:
if n["t"] != 0:
continue
chosen = None
for nk in node_keys(n["k"], master):
if len(nk) < 32:
continue
key, iv = file_key(nk)
name = attr_name(n["a"], key)
if name:
chosen = (key, iv, name)
break
if chosen is None:
undecodable.append(n["h"])
continue
key, iv, name = chosen
jobs.append((n["h"], key, iv, n["s"], os.path.join(relpath_of(n["p"]), name)))
if undecodable:
print(f"AVISO: {len(undecodable)} nos sem chave decifravel, ignorados", flush=True)
total = sum(j[3] for j in jobs)
print(f"{len(jobs)} arquivos, {total/1e9:.2f} GB, {a.workers} conexoes", flush=True)
state = {"bytes": 0, "done": 0, "skipped": 0}
t0 = time.time()
stop = threading.Event()
def ticker():
while not stop.wait(30):
el = time.time() - t0
print(f"[{el:6.0f}s] ok={state['done']} skip={state['skipped']}/{len(jobs)} "
f"{state['bytes']/1e6:8.0f} MB {state['bytes']/1e6/el:5.2f} MB/s", flush=True)
threading.Thread(target=ticker, daemon=True).start()
errors = []
with ThreadPoolExecutor(max_workers=a.workers) as ex:
futs = {ex.submit(download, j, a.dest, folder_id, master, state): j for j in jobs}
for f, j in futs.items():
try:
f.result()
except Exception as e:
errors.append((j[4], repr(e)))
stop.set()
print(f"FIM em {time.time()-t0:.0f}s ok={state['done']} skip={state['skipped']} err={len(errors)}", flush=True)
for p, e in errors[:40]:
print("ERRO", p, e, flush=True)
sys.exit(1 if errors else 0)
if __name__ == "__main__":
main()
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