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Failu lejupielāde no tīmekļa, izmantojot Python

Pieprasījumi ir daudzpusīga HTTP bibliotēka python ar dažādām lietojumprogrammām. Viena no tās lietojumprogrammām ir faila lejupielāde no tīmekļa, izmantojot faila URL. Uzstādīšana: First of all you would need to download the requests library. You can directly install it using pip by typing following command:
pip install requests
Or download it directly from šeit un instalējiet manuāli.

Failu lejupielāde

Python3
# imported the requests library import requests image_url = 'https://www.python.org/static/community_logos/python-logo-master-v3-TM.webp' # URL of the image to be downloaded is defined as image_url r = requests.get(image_url) # create HTTP response object # send a HTTP request to the server and save # the HTTP response in a response object called r with open('python_logo.webp''wb') as f: # Saving received content as a png file in # binary format # write the contents of the response (r.content) # to a new file in binary mode. f.write(r.content) 
This small piece of code written above will download the following image from the web. Now check your local directory(the folder where this script resides) and you will find this image: All we need is the URL of the image source. (You can get the URL of image source by right-clicking on the image and selecting the View Image option.)

Lejupielādējiet lielus failus

HTTP atbildes saturs ( r.content ) ir tikai virkne, kas glabā faila datus. Tāpēc lielu failu gadījumā visus datus nevarēs saglabāt vienā virknē. Lai novērstu šo problēmu, mēs veicam dažas izmaiņas programmā:
  • Tā kā visus failu datus nevar glabāt vienā virknē, ko mēs izmantojam r.iter_content metode datu ielādei pa daļām, norādot gabala lielumu.
  •  r = requests.get(URL stream = True)
    Setting straume parametrs uz Taisnība izraisīs tikai atbilžu galvenes lejupielādi, un savienojums paliks atvērts. Tas ļauj izvairīties no satura uzreiz nolasīšanas atmiņā, lai iegūtu lielas atbildes. Ikreiz tiks ielādēts fiksēts gabals r.iter_content is iterated. Here is an example: Python3
    import requests file_url = 'http://codex.cs.yale.edu/avi/db-book/db4/slide-dir/ch1-2.pdf' r = requests.get(file_url stream = True) with open('python.pdf''wb') as pdf: for chunk in r.iter_content(chunk_size=1024): # writing one chunk at a time to pdf file if chunk: pdf.write(chunk) 

    Videoklipu lejupielāde



    Šajā piemērā mēs esam ieinteresēti lejupielādēt visas pieejamās videolekcijas par šo tēmu tīmekļa lapa . Ir pieejams viss šīs lekcijas arhīvs šeit . So we first scrape the webpage to extract all video links and then download the videos one by one. Python3
    import requests from bs4 import BeautifulSoup '''  URL of the archive web-page which provides link to  all video lectures. It would have been tiring to  download each video manually.  In this example we first crawl the webpage to extract  all the links and then download videos.  ''' # specify the URL of the archive here  archive_url = 'https://public.websites.umich.edu/errors/404.html def get_video_links(): # create response object  r = requests.get(archive_url) # create beautiful-soup object  soup = BeautifulSoup(r.content'html5lib') # find all links on web-page  links = soup.findAll('a') # filter the link sending with .mp4  video_links = [archive_url + link['href'] for link in links if link['href'].endswith('mp4')] return video_links def download_video_series(video_links): for link in video_links:  '''iterate through all links in video_links   and download them one by one''' # obtain filename by splitting url and getting  # last string  file_name = link.split('/')[-1] print( 'Downloading file:%s'%file_name) # create response object  r = requests.get(link stream = True) # download started  with open(file_name 'wb') as f: for chunk in r.iter_content(chunk_size = 1024*1024): if chunk: f.write(chunk) print( '%s downloaded!n'%file_name ) print ('All videos downloaded!') return if __name__ == '__main__': # getting all video links  video_links = get_video_links() # download all videos  download_video_series(video_links) 
    Advantages of using Requests library to download web files are:
    • Tīmekļa direktorijus var viegli lejupielādēt, atkārtojot vietni rekursīvi!
    • Šī ir no pārlūkprogrammas neatkarīga metode un daudz ātrāka!
    • Var vienkārši nokasīt tīmekļa lapu, lai tīmekļa lapā iegūtu visus failu URL un tādējādi lejupielādētu visus failus vienā komandā -

      Tīmekļa skrāpēšanas ieviešana Python, izmantojot BeautifulSoup

    Šī emuāra autors ir Nikhils Kumars.