Table Of Contents
Table Of Contents

Source code for gluoncv.utils.download

"""Download files with progress bar."""
import os
import hashlib
import requests
from tqdm import tqdm

[docs]def check_sha1(filename, sha1_hash): """Check whether the sha1 hash of the file content matches the expected hash. Parameters ---------- filename : str Path to the file. sha1_hash : str Expected sha1 hash in hexadecimal digits. Returns ------- bool Whether the file content matches the expected hash. """ sha1 = hashlib.sha1() with open(filename, 'rb') as f: while True: data = f.read(1048576) if not data: break sha1.update(data) sha1_file = sha1.hexdigest() l = min(len(sha1_file), len(sha1_hash)) return sha1.hexdigest()[0:l] == sha1_hash[0:l]
[docs]def download(url, path=None, overwrite=False, sha1_hash=None): """Download an given URL Parameters ---------- url : str URL to download path : str, optional Destination path to store downloaded file. By default stores to the current directory with same name as in url. overwrite : bool, optional Whether to overwrite destination file if already exists. sha1_hash : str, optional Expected sha1 hash in hexadecimal digits. Will ignore existing file when hash is specified but doesn't match. Returns ------- str The file path of the downloaded file. """ if path is None: fname = url.split('/')[-1] else: path = os.path.expanduser(path) if os.path.isdir(path): fname = os.path.join(path, url.split('/')[-1]) else: fname = path if overwrite or not os.path.exists(fname) or (sha1_hash and not check_sha1(fname, sha1_hash)): dirname = os.path.dirname(os.path.abspath(os.path.expanduser(fname))) if not os.path.exists(dirname): os.makedirs(dirname) print('Downloading %s from %s...'%(fname, url)) r = requests.get(url, stream=True) if r.status_code != 200: raise RuntimeError("Failed downloading url %s"%url) total_length = r.headers.get('content-length') with open(fname, 'wb') as f: if total_length is None: # no content length header for chunk in r.iter_content(chunk_size=1024): if chunk: # filter out keep-alive new chunks f.write(chunk) else: total_length = int(total_length) for chunk in tqdm(r.iter_content(chunk_size=1024), total=int(total_length / 1024. + 0.5), unit='KB', unit_scale=False, dynamic_ncols=True): f.write(chunk) if sha1_hash and not check_sha1(fname, sha1_hash): raise UserWarning('File {} is downloaded but the content hash does not match. ' \ 'The repo may be outdated or download may be incomplete. ' \ 'If the "repo_url" is overridden, consider switching to ' \ 'the default repo.'.format(fname)) return fname