Robust.Packaging system (#3016)

Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Tools/download_manifest_file.py

@@ -0,0 +1,81 @@
+import argparse
+import json
+import os
+import requests
+import struct
+import typing
+import zstandard
+
+# Very crappy script to download blobs from manifest download protocol.
+# Not well-written. DO NOT use as a thorough protocol reference.
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("server", help="Game server address. Must not have a trailing /")
+    parser.add_argument("file_path", help="The VFS path to download from the manifest")
+    parser.add_argument("-o", "--output", help="Output path to store the file at. Defaults to file name")
+    args = parser.parse_args()
+
+    server = args.server
+    file_path = args.file_path
+    output = args.output
+
+    if not output:
+        output = file_path.split("/")[-1]
+
+    server_info = requests.get(f"{server}/info").json()
+    (manifest_url, dl_url) = cdn_urls(server, server_info["build"])
+
+    manifest = requests.get(manifest_url).text
+
+    manifest_lines = iter(manifest.splitlines())
+
+    header = next(manifest_lines)
+    print(f"header: {header}")
+
+    i = 0
+    for line in manifest_lines:
+        (hash, path) = line.split(" ", maxsplit=1)
+        if path == file_path:
+            break
+        i += 1
+    else:
+        print("Unable to find file in manifest")
+        exit(1)
+
+    print(f"File index: {i}")
+
+    dl_req = struct.pack("<I", i)
+    dl_resp = requests.post(dl_url, data=dl_req, headers={"Content-Type": "application/octet-stream", "X-Robust-Download-Protocol": "1"}, stream=True)
+    dl_resp.raise_for_status()
+
+    dl_head = struct.unpack("<I", dl_resp.raw.read(4))[0]
+    print(dl_head)
+
+    blob_compress_enabled = (dl_head & 1) != 0
+
+    file_length = struct.unpack("<I", dl_resp.raw.read(4))[0]
+    read_length = file_length
+    blob_is_compressed = False
+    if blob_compress_enabled:
+        compr_length = struct.unpack("<I", dl_resp.raw.read(4))[0]
+        if compr_length != 0:
+            blob_is_compressed = True
+            read_length = compr_length
+
+    data = dl_resp.raw.read(read_length)
+
+    if blob_is_compressed:
+        data = zstandard.decompress(data)
+
+    open(output, "wb").write(data)
+
+
+def cdn_urls(server: str, build_info) -> typing.Tuple[str, str]:
+    if build_info["acz"]:
+        return (f"{server}/manifest.txt", f"{server}/download")
+
+    return build_info["manifest_url"], build_info["manifest_download_url"]
+
+if __name__ == "__main__":
+    main()