Parse JSON into objects

dataclass_helper.py

from dataclasses import fields


def init_from_json(cls, json):
    return cls(**{f.name: json.get(f.name) for f in fields(cls)})

item.py

from dataclass_helper import init_from_json


@dataclass
class Item:
    id: str
    kind: str
    created_utc: float
    permalink: str
    title: str
    selftext_html: str
    link_title: str
    body: str
    link_url: str

    def comment_url(self):
        return f"https://beta.reddit.com/{self.permalink}"

    def posted_on(self):
        return datetime.datetime.fromtimestamp(self.created_utc)

    def is_comment(self):
        return self.kind == "t1"

    def is_post(self):
        return self.kind == "t3"

def parse(...):
    ...
    item = init_from_json(Item, raw_item)
    
    # Uses another intermediary dict, but this felt OK for now.
    #
    args = dict(
        site=site,
        fetched_on=datetime.date.today(),
        posted_on=item.posted_on(),
        comment_url=item.comment_url(),
    )

    if item.is_post():
        fetched += 1
        args["title"] = item.title
        args["content"] = item.selftext_html or ""
    elif item.is_comment():
        fetched += 1
        args["title"] = item.link_title
        args["link_url"] = item.link_url
        args["content"] = item.body
    else:
        print(f"unknown link: {item}")

    if debug:
        # Don't create db
        return

    Post.create(**args)

    ...