pip install requestsOr download it directly from Qui e installarlo manualmente.
Download di file
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.) Scarica file di grandi dimensioni
Il contenuto della risposta HTTP ( r.content ) non è altro che una stringa che memorizza i dati del file. Non sarà quindi possibile salvare tutti i dati in un'unica stringa in caso di file di grandi dimensioni. Per ovviare a questo problema apportiamo alcune modifiche al nostro programma:r = requests.get(URL stream = True)Setting flusso parametro a VERO causerà il download solo delle intestazioni di risposta e la connessione rimarrà aperta. Ciò evita di leggere il contenuto tutto in una volta in memoria per risposte di grandi dimensioni. Ogni volta verrà caricato un pezzo fisso while 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)
Download di video
In questo esempio ci interessa scaricare tutte le videolezioni disponibili sull'argomento pagina web . Tutti gli archivi di questa conferenza sono disponibili Qui . 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: - È possibile scaricare facilmente le directory Web eseguendo un'iterazione ricorsiva attraverso il sito Web!
- Questo è un metodo indipendente dal browser e molto più veloce!
- È possibile semplicemente raschiare una pagina Web per ottenere tutti gli URL dei file su una pagina Web e quindi scaricare tutti i file in un unico comando-
Implementazione del Web Scraping in Python con BeautifulSoup