lumbunglib/lumbung-feed-aggregator/rss_aggregator.py

#!/bin/python3

#lumbung.space rss feed aggregator
#© 2021 roel roscam abbing gplv3 etc

import requests
import jinja2
import os
import shutil
import feedparser
from urllib.parse import urlparse
from ast import literal_eval as make_tuple
from slugify import slugify
from bs4 import BeautifulSoup
import time
import arrow


def write_etag(feed_name, feed_data):
    """
    save timestamp of when feed was last modified
    """
    etag = ''
    modified = ''
    
    if 'etag' in feed_data:
        etag = feed_data.etag
    if 'modified' in feed_data:
        modified = feed_data.modified

    if etag or modified:
        with open(os.path.join('etags',feed_name +'.txt'),'w') as f:
            f.write(str((etag, modified)))

def get_etag(feed_name):
    """
    return timestamp of when feed was last modified
    """
    fn = os.path.join('etags',feed_name +'.txt')
    etag = ''
    modified = ''

    if os.path.exists(fn):
        etag, modified = make_tuple(open(fn,'r').read())

    return etag, modified

def create_frontmatter(entry):
    """
    parse RSS metadata and return as frontmatter 
    """
    if 'published' in entry:
        published = entry.published_parsed
    if 'updated' in entry:
        published = entry.updated_parsed

    published = arrow.get(published)

    if 'author' in entry:
        author = entry.author
    else:
        author = ''

    tags = []
    if 'tags' in entry:
        #TODO finish categories
        for t in entry.tags:
            tags.append(t['term'])

    frontmatter = {
    'title':entry.title,
    'date': published.format(),
    'summary': '',
    'author': author,
    'original_link': entry.link,
    'feed_name': entry['feed_name'],
    'tags': str(tags)
    }

    return frontmatter

def create_post(post_dir, entry):
    """
    write hugo post based on RSS entry
    """
    frontmatter = create_frontmatter(entry)

    if not os.path.exists(post_dir):
        os.makedirs(post_dir)

    if 'content' in entry:
        post_content = entry.content[0].value
    else:
        post_content = entry.summary

    parsed_content = parse_posts(post_dir, post_content)

    with open(os.path.join(post_dir,'index.html'),'w') as f: #n.b. .html 
        post = template.render(frontmatter=frontmatter, content=parsed_content)
        f.write(post)
        print('created post for', entry.title, '({})'.format(entry.link))

def grab_media(post_directory, url):
    """
    download media linked in post to have local copy
    if download succeeds return new local path otherwise return url
    """
    image = urlparse(url).path.split('/')[-1]

    try:
        if not os.path.exists(os.path.join(post_directory, image)):
            #TODO: stream is true is a conditional so we could check the headers for things, mimetype etc
            response = requests.get(url, stream=True)
            if response.ok:
                with open(os.path.join(post_directory, image), 'wb') as img_file:
                    shutil.copyfileobj(response.raw, img_file)
                    print('Downloaded cover image', image)
                    return image
            return image
        elif os.path.exists(os.path.join(post_directory, image)):
            return image

    except Exception as e:
        print('Failed to download image', url)
        print(e)
    return url


def parse_posts(post_dir, post_content):
    """
    parse the post content to for media items
    replace foreign image with local copy
    filter out iframe sources not in allowlist
    """
    soup = BeautifulSoup(post_content, "html.parser")
    allowed_iframe_sources = ['youtube.com', 'vimeo.com', 'tv.lumbung.space']
    media = []

    for img in soup(['img','object']):
        local_image = grab_media(post_dir, img['src'])
        if img['src'] != local_image:
            img['src'] = local_image

    for iframe in soup(['iframe']):
        if not any(source in iframe['src'] for source in allowed_iframe_sources):
            print('filtered iframe: {}...'.format(iframe['src'][:25]))
            iframe.decompose()
    return soup.decode()

def grab_feed(feed_url):
    """
    check whether feed has been updated
    download & return it if it has 
    """
    feed_name = urlparse(feed_url).netloc
    
    etag, modified = get_etag(feed_name)

    try:
        if modified:
            data = feedparser.parse(feed_url, modified=modified)
        elif etag:
            data = feedparser.parse(feed_url, etag=etag)
        else:
            data = feedparser.parse(feed_url)
    except Exception as e:
        print('Error grabbing feed')
        print(feed_name)
        print(e)
        return False

    print(data.status, feed_url)
    if data.status == 200:
        #304 means the feed has not been modified since we last checked
        write_etag(feed_name, data)
        return data
    return False
    

feed_urls = open('feeds_list.txt','r').read().splitlines()

start = time.time()

if not os.path.exists('etags'):
    os.mkdir('etags')


env = jinja2.Environment(
    loader=jinja2.FileSystemLoader(os.path.curdir) 
    )

output_dir = os.environ.get('OUTPUT_DIR', '/home/r/Programming/lumbung.space/lumbung.space-web/content/posts/')
#output_dir = os.environ.get('OUTPUT_DIR', 'network/')

if not os.path.exists(output_dir):
    os.makedirs(output_dir)

template = env.get_template('post_template.md')

#add iframe to the allowlist of feedparser's sanitizer,
#this is now handled in parse_post() 
feedparser.sanitizer._HTMLSanitizer.acceptable_elements |= {'iframe'}   

for feed_url in feed_urls:

    feed_name = urlparse(feed_url).netloc

    feed_dir = os.path.join(output_dir, feed_name)

    if not os.path.exists(feed_dir):
        os.makedirs(feed_dir)

    existing_posts = os.listdir(feed_dir)

    data = grab_feed(feed_url)

    if data:
        for entry in data.entries:
             # if 'tags' in entry:
             #     for tag in entry.tags:
             #        for x in ['lumbung.space', 'D15', 'lumbung']:
             #            if x in tag['term']:
             #                print(entry.title)
            entry['feed_name'] = feed_name

            post_name = slugify(entry.title)
            post_dir = os.path.join(output_dir, feed_name, post_name)
            
            if post_name not in existing_posts: 
            #if there is a blog entry we dont already have, make it
                create_post(post_dir, entry)

            elif post_name in existing_posts: 
                #if we already have it, update it
                create_post(post_dir, entry)                
                existing_posts.remove(post_name) # create list of posts which have not been returned by the feed

        for post in existing_posts: 
            #remove blog posts no longer returned by the RSS feed 
            print('deleted', post) 
            shutil.rmtree(os.path.join(feed_dir, slugify(post)))



end = time.time()

print(end - start)