PRENOS DATOTEK IZ SPLETA S POMOČJO PYTHONA

Zahteve je vsestranska knjižnica HTTP v pythonu z različnimi aplikacijami. Ena od njegovih aplikacij je prenos datoteke s spleta z uporabo URL-ja datoteke. Namestitev: 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 tukaj in namestite ročno.

Prenašanje datotek

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.)

Prenesite velike datoteke

Vsebina odziva HTTP ( r.vsebina ) ni nič drugega kot niz, ki shranjuje podatke datoteke. Tako v primeru velikih datotek ne bo mogoče shraniti vseh podatkov v enem nizu. Da bi odpravili to težavo, naredimo nekaj sprememb v našem programu:

Ker vseh podatkov datoteke ni mogoče shraniti z enim nizom, ki ga uporabljamo r.iter_content metoda za nalaganje podatkov v kosih, ki določajo velikost kosa.

 r = requests.get(URL stream = True)

Setting tok parameter za res bo povzročil samo prenos glav odgovorov in povezava ostane odprta. S tem se izognete branju celotne vsebine v pomnilnik za velike odzive. Vsakič, ko bo naložen fiksni kos 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  )

Prenašanje videoposnetkov

V tem primeru nas zanima prenos vseh razpoložljivih video predavanj o tem spletna stran . Vsi arhivi tega predavanja so na voljo tukaj . 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:

Spletne imenike lahko preprosto prenesete z rekurzivnim ponavljanjem po spletnem mestu!
To je način, neodvisen od brskalnika in veliko hitrejši!
Enostavno lahko postrgamo spletno stran, da dobimo vse URL-je datotek na spletni strani in tako prenesemo vse datoteke z enim ukazom-
Implementacija spletnega strganja v Pythonu z BeautifulSoup

Ta blog je prispeval Nikhil Kumar. Ustvari kviz