lambda_handler.py

import os
import re
import json
import boto3
from datetime import datetime, timedelta
from string import Template
from html import escape


CHAPTERS_LENGHT = int(os.environ['CHAPTERS_LENGHT'])


def lambda_handler(event, context):
    print(event["rawPath"])
    CONFIG = json.loads(os.environ['CONFIG'])
    NEWS_TABLE = CONFIG[event["rawPath"]]["table"]
    S3_PREFIX = CONFIG[event["rawPath"]]["s3_prefix"]
    FEED_TPL = Template(open(CONFIG[event["rawPath"]]["feed_tpl"]).read())
    EPISODE_TPL = Template(open("item.tpl").read())
    
    dynamodb = boto3.resource('dynamodb')
    table = dynamodb.Table(NEWS_TABLE)
    items = table.scan()

    feed = {'build_date': datetime.now().strftime("%a, %d %b %Y %H:%M:%S GMT")}
    feed['items'] = ""

    published = []
    
    for i in items['Items']:
        if 'meta' in i.keys() and i['meta']['published']:
            published.append(i)

    for record in sorted(published, reverse=True, key=lambda x: int(x['episode'].split("-")[-1])):
        episode = {}
        meta = record['meta']
        episode_number = record['episode']
        if "season" in meta:
            episode['season'] = meta['season']
            if meta['season'] > 1:
                episode_number += f' (S{meta["season"]}E{meta["episode"]})'
        else:
            episode['season'] = record['episode'][1:].split("-")[0]
        episode['title'] = f'{episode_number}. {meta["title"]}'
        if 'guest' in meta:
            episode['title'] += ' (гостевой)'
        episode['link'] = meta['web_url']
        episode['mp3_url'] = f'{S3_PREFIX}{record["episode"]}.mp3'
        episode['duration_seconds'] = str(timedelta(seconds=int(meta['duration_seconds'])))
        episode['image_url'] = f'{S3_PREFIX}{record["episode"]}.png'
        episode['mp3_size_bytes'] = meta['mp3_size_bytes']
        episode['episode'] = meta['episode']

        # construct description
        if 'description_html' in meta:
            description_html = meta['description_html']
        else:
            if 'guest' in meta:
                description_html = f'<p><strong>Тема выпуска {meta["title"]}</strong></p>\n<p>В гостях у подкаста `Data Coffee` {meta["guest"]["title"]} — {meta["guest"]["name"]}</p>\n<p><br></p>\n'
            else:
                description_html = '<p><strong>Ведущие подкаста `Data Coffee` обсуждают новости и делятся своими мыслями!</strong></p>\n<p><br></p>\n'
            if 'promo_text' in meta:
                description_html += f'<p>{meta["promo_text"]}</p><p><br></p>\n'
            description_html += '<p>Shownotes:</p>\n'
            prev_dttm = datetime.strptime(record['records'][-1], "%m/%d/%Y, %H:%M:%S")
            for chapter in [i for i in record['news'] if len(i['chapters'])]:
                dttm = datetime.strptime(chapter['chapters'][-1], "%m/%d/%Y, %H:%M:%S")
                time_delta = dttm - prev_dttm
                text, links = split_news(chapter['text'])
                description_html += f'<p>{format_time(time_delta)} '
                if links:
                    description_html += f'<a href="{links[0]}">{cut_text(text)}</a>'
                else:
                    description_html += cut_text(text)
                description_html += '</p>\n'
            if 'image_src' in meta:
                description_html += f'<p><br></p>\n<p><a href="{meta["image_src"]}">Обложка</a></p>\n'
            description_html += '<p>Сайт: <a href="https://datacoffee.link/">https://datacoffee.link</a>, '
            description_html += 'канал в Telegram: <a href="https://t.me/datacoffee">https://t.me/datacoffee</a>, '
            description_html += 'профиль в Twitter: <a href="https://twitter.com/_DataCoffee_">https://twitter.com/_DataCoffee_</a></p>'
        episode['description_html'] = description_html

        episode['description_escaped'] = escape(episode['description_html'])
        episode['guid'] = meta['guid']
        episode['pub_date'] = datetime.fromtimestamp(meta['pub_date_epoch']).strftime("%a, %d %b %Y %H:%M:%S GMT")
        feed['items'] += EPISODE_TPL.substitute(episode)

    return {
        'statusCode': 200,
        'body': FEED_TPL.substitute(feed)
    }


def cut_text(text):
    if len(text) > CHAPTERS_LENGHT:
        text = text[:CHAPTERS_LENGHT-3].strip() + "..."
    return text


def split_news(news_str):
    links = re.findall(r'(https?://[^\s]+)', news_str)
    text = news_str.strip()
    for link in links:
        text = text.replace(link, '')
    text = re.sub(' +', ' ', text).strip().replace('"', "'")
    text = text[:1].upper() + text[1:]
    return (text, links)


def format_time(tdelta):
    # days = tdelta.days
    hours, rem = divmod(tdelta.seconds, 3600)
    minutes, seconds = divmod(rem, 60)
    return f"{hours:02}:{minutes:02}:{seconds:02}:00"