Python根據URL地址下載文件並保存至對應目錄

Python根據URL地址下載文件並保存至對應目錄

引言

在編程中經常會遇到圖片等數據集將圖片等數據以URL形式存儲在txt文檔中，爲便於後續的分析，需要將其下載下來，並按照文件夾分類存儲。本文以Github中Alexander Kim提供的圖片分類數據集爲例，下載其提供的圖片樣本並分類保存
Python 3.6.5，Anaconda， VSCode

1. 下載數據集文件

建立項目文件夾，下載上述Github項目中的raw_data文件夾，並保存至項目目錄中。

2. 獲取樣本文件位置

編寫get_doc_path.py，根據根目錄位置，獲取目錄及其子目錄所有數據集文件

import os


def get_file(root_path, all_files={}):
    '''
    遞歸函數，遍歷該文檔目錄和子目錄下的所有文件，獲取其path
    '''
    files = os.listdir(root_path)
    for file in files:
        if not os.path.isdir(root_path + '/' + file):   # not a dir
            all_files[file] = root_path + '/' + file
        else:  # is a dir
            get_file((root_path+'/'+file), all_files)
    return all_files


if __name__ == '__main__':
    path = './raw_data'
    print(get_file(path))

3. 下載文件

3.1 讀取url列表並

for filename, path in paths.items():
        print('reading file: {}'.format(filename))
        with open(path, 'r') as f:
            lines = f.readlines()
            url_list = []
            for line in lines:
                url_list.append(line.strip('\n'))
            print(url_list)

3.2 創建文件夾

foldername = "./picture_get_by_url/pic_download/{}".format(filename.split('.')[0])
if not os.path.exists(folder_path):
        print("Selected folder not exist, try to create it.")
        os.makedirs(folder_path)

3.3 下載圖片

def get_pic_by_url(folder_path, lists):
    if not os.path.exists(folder_path):
        print("Selected folder not exist, try to create it.")
        os.makedirs(folder_path)
    for url in lists:
        print("Try downloading file: {}".format(url))
        filename = url.split('/')[-1]
        filepath = folder_path + '/' + filename
        if os.path.exists(filepath):
            print("File have already exist. skip")
        else:
            try:
                urllib.request.urlretrieve(url, filename=filepath)
            except Exception as e:
                print("Error occurred when downloading file, error message:")
                print(e)

4. 完整源碼

4.1 get_doc_path.py

import os


def get_file(root_path, all_files={}):
    '''
    遞歸函數，遍歷該文檔目錄和子目錄下的所有文件，獲取其path
    '''
    files = os.listdir(root_path)
    for file in files:
        if not os.path.isdir(root_path + '/' + file):   # not a dir
            all_files[file] = root_path + '/' + file
        else:  # is a dir
            get_file((root_path+'/'+file), all_files)
    return all_files


if __name__ == '__main__':
    path = './raw_data'
    print(get_file(path))

4.2 get_pic.py

import get_doc_path
import os
import urllib.request


def get_pic_by_url(folder_path, lists):
    if not os.path.exists(folder_path):
        print("Selected folder not exist, try to create it.")
        os.makedirs(folder_path)
    for url in lists:
        print("Try downloading file: {}".format(url))
        filename = url.split('/')[-1]
        filepath = folder_path + '/' + filename
        if os.path.exists(filepath):
            print("File have already exist. skip")
        else:
            try:
                urllib.request.urlretrieve(url, filename=filepath)
            except Exception as e:
                print("Error occurred when downloading file, error message:")
                print(e)


if __name__ == "__main__":
    root_path = './picture_get_by_url/raw_data'
    paths = get_doc_path.get_file(root_path)
    print(paths)
    for filename, path in paths.items():
        print('reading file: {}'.format(filename))
        with open(path, 'r') as f:
            lines = f.readlines()
            url_list = []
            for line in lines:
                url_list.append(line.strip('\n'))
            foldername = "./picture_get_by_url/pic_download/{}".format(filename.split('.')[0])
            get_pic_by_url(foldername, url_list)

4.3 運行結果

執行get_pic.py
當程序意外停止或再次執行時，程序會自動跳過文件夾中已下載的文件，繼續下載未下載的內容

{‘urls_drawings.txt’: ‘./picture_get_by_url/raw_data/drawings/urls_drawings.txt’, ‘urls_hentai.txt’: ‘./picture_get_by_url/raw_data/hentai/urls_hentai.txt’, ‘urls_neutral.txt’: ‘./picture_get_by_url/raw_data/neutral/urls_neutral.txt’, ‘urls_porn.txt’: ‘./picture_get_by_url/raw_data/porn/urls_porn.txt’, ‘urls_sexy.txt’: ‘./picture_get_by_url/raw_data/sexy/urls_sexy.txt’}
reading file: urls_drawings.txt
Try downloading file: http://41.media.tumblr.com/a3e460c294cce7e28fcf09293b88ba88/tumblr_nsfnh6T6OG1qg6mvgo2_1280.jpg
Try downloading file: http://41.media.tumblr.com/tumblr_ln936uLBcr1qiiouso1_500.jpg
Try downloading file: http://ak1.polyvoreimg.com/cgi/img-thing/size/l/tid/44576395.jpg
Error occurred when downloading file, error message:
HTTP Error 502: No data received from server or forwarder
Try downloading file: http://akicocotte.weblike.jp/gaugau/01.jpg
Try downloading file: http://animewriter.files.wordpress.com/2009/01/nagisa-has-died.jpg
Try downloading file: http://cdn.awwni.me/11wcd.jpg
Try downloading file: http://cdn.awwni.me/11yu8.jpg
Try downloading file: http://cdn.awwni.me/126nk.jpg
Try downloading file: http://cdn.awwni.me/12lbq.jpg
Try downloading file: http://cdn.awwni.me/12nxd.jpg
Try downloading file: http://cdn.awwni.me/12oo1.jpg
Try downloading file: http://cdn.awwni.me/12pk4.jpg
Try downloading file: http://cdn.awwni.me/12rlf.jpg
Try downloading file: http://cdn.awwni.me/12vgb.jpg
Try downloading file: http://cdn.awwni.me/12vo6.jpg
Try downloading file: http://cdn.awwni.me/12wu5.jpg
Try downloading file: http://cdn.awwni.me/12x7f.jpg
Try downloading file: http://cdn.awwni.me/12xvj.jpg
Try downloading file: http://cdn.awwni.me/12xzw.jpg
Try downloading file: http://cdn.awwni.me/12z6q.jpg
Try downloading file: http://cdn.awwni.me/13386.jpg
Try downloading file: http://cdn.awwni.me/133n7.jpg