pyfedi/app/community/util.py

from datetime import datetime, timedelta
from threading import Thread
from time import sleep
from typing import List
import requests
from PIL import Image, ImageOps
from flask import request, abort, g, current_app
from flask_login import current_user
from pillow_heif import register_heif_opener

from app import db, cache, celery
from app.activitypub.signature import post_request
from app.activitypub.util import find_actor_or_create, actor_json_to_model, post_json_to_model
from app.constants import POST_TYPE_ARTICLE, POST_TYPE_LINK, POST_TYPE_IMAGE
from app.models import Community, File, BannedInstances, PostReply, PostVote, Post, utcnow, CommunityMember, Site, \
    Instance, Notification, User
from app.utils import get_request, gibberish, markdown_to_html, domain_from_url, validate_image, allowlist_html, \
    html_to_markdown, is_image_url, ensure_directory_exists, inbox_domain, post_ranking, shorten_string
from sqlalchemy import desc, text
import os
from opengraph_parse import parse_page


allowed_extensions = ['.gif', '.jpg', '.jpeg', '.png', '.webp', '.heic']


def search_for_community(address: str):
    if address.startswith('!'):
        name, server = address[1:].split('@')

        banned = BannedInstances.query.filter_by(domain=server).first()
        if banned:
            reason = f" Reason: {banned.reason}" if banned.reason is not None else ''
            raise Exception(f"{server} is blocked.{reason}")  # todo: create custom exception class hierarchy

        already_exists = Community.query.filter_by(ap_id=address[1:]).first()
        if already_exists:
            return already_exists

        # Look up the profile address of the community using WebFinger
        # todo: try, except block around every get_request
        webfinger_data = get_request(f"https://{server}/.well-known/webfinger",
                                     params={'resource': f"acct:{address[1:]}"})
        if webfinger_data.status_code == 200:
            webfinger_json = webfinger_data.json()
            for links in webfinger_json['links']:
                if 'rel' in links and links['rel'] == 'self':  # this contains the URL of the activitypub profile
                    type = links['type'] if 'type' in links else 'application/activity+json'
                    # retrieve the activitypub profile
                    community_data = get_request(links['href'], headers={'Accept': type})
                    # to see the structure of the json contained in community_data, do a GET to https://lemmy.world/c/technology with header Accept: application/activity+json
                    if community_data.status_code == 200:
                        community_json = community_data.json()
                        community_data.close()
                        if community_json['type'] == 'Group':
                            community = actor_json_to_model(community_json, name, server)
                            if current_app.debug:
                                retrieve_mods_and_backfill(community.id)
                            else:
                                retrieve_mods_and_backfill.delay(community.id)
                            return community
        return None


@celery.task
def retrieve_mods_and_backfill(community_id: int):
    with current_app.app_context():
        community = Community.query.get(community_id)
        site = Site.query.get(1)
        if community.ap_moderators_url:
            mods_request = get_request(community.ap_moderators_url, headers={'Accept': 'application/activity+json'})
            if mods_request.status_code == 200:
                mods_data = mods_request.json()
                mods_request.close()
                if mods_data and mods_data['type'] == 'OrderedCollection' and 'orderedItems' in mods_data:
                    for actor in mods_data['orderedItems']:
                        sleep(0.5)
                        user = find_actor_or_create(actor)
                        if user:
                            existing_membership = CommunityMember.query.filter_by(community_id=community.id, user_id=user.id).first()
                            if existing_membership:
                                existing_membership.is_moderator = True
                            else:
                                new_membership = CommunityMember(community_id=community.id, user_id=user.id, is_moderator=True)
                                db.session.add(new_membership)
                    db.session.commit()

        # only backfill nsfw if nsfw communities are allowed
        if (community.nsfw and not site.enable_nsfw) or (community.nsfl and not site.enable_nsfl):
            return

        # download 50 old posts
        if community.ap_public_url:
            outbox_request = get_request(community.ap_public_url + '/outbox', headers={'Accept': 'application/activity+json'})
            if outbox_request.status_code == 200:
                outbox_data = outbox_request.json()
                outbox_request.close()
                if outbox_data['type'] == 'OrderedCollection' and 'orderedItems' in outbox_data:
                    activities_processed = 0
                    for activity in outbox_data['orderedItems']:
                        user = find_actor_or_create(activity['object']['actor'])
                        if user:
                            post = post_json_to_model(activity['object']['object'], user, community)
                            post.ap_create_id = activity['object']['id']
                            post.ap_announce_id = activity['id']
                            post.ranking = post_ranking(post.score, post.posted_at)
                            db.session.commit()

                        activities_processed += 1
                        if activities_processed >= 50:
                            break
                    c = Community.query.get(community.id)
                    c.post_count = activities_processed
                    c.last_active = utcnow()
                    db.session.commit()


def community_url_exists(url) -> bool:
    community = Community.query.filter_by(ap_profile_id=url).first()
    return community is not None


def actor_to_community(actor) -> Community:
    actor = actor.strip()
    if '@' in actor:
        community = Community.query.filter_by(banned=False, ap_id=actor).first()
    else:
        community = Community.query.filter_by(name=actor, banned=False, ap_id=None).first()
    return community


@cache.memoize(timeout=50)
def opengraph_parse(url):
    try:
        return parse_page(url)
    except Exception as ex:
        return None


def url_to_thumbnail_file(filename) -> File:
    unused, file_extension = os.path.splitext(filename)
    response = requests.get(filename, timeout=5)
    if response.status_code == 200:
        new_filename = gibberish(15)
        directory = 'app/static/media/posts/' + new_filename[0:2] + '/' + new_filename[2:4]
        ensure_directory_exists(directory)
        final_place = os.path.join(directory, new_filename + file_extension)
        with open(final_place, 'wb') as f:
            f.write(response.content)
        with Image.open(final_place) as img:
            img = ImageOps.exif_transpose(img)
            img.thumbnail((150, 150))
            img.save(final_place)
            thumbnail_width = img.width
            thumbnail_height = img.height
        return File(file_name=new_filename + file_extension, thumbnail_width=thumbnail_width,
                    thumbnail_height=thumbnail_height, thumbnail_path=final_place,
                    source_url=filename)


def save_post(form, post: Post):
    post.nsfw = form.nsfw.data
    post.nsfl = form.nsfl.data
    post.notify_author = form.notify_author.data
    if form.type.data == '' or form.type.data == 'discussion':
        post.title = form.discussion_title.data
        post.body = form.discussion_body.data
        post.body_html = markdown_to_html(post.body)
        post.type = POST_TYPE_ARTICLE
    elif form.type.data == 'link':
        post.title = form.link_title.data
        url_changed = post.id is None or form.link_url.data != post.url
        post.url = form.link_url.data
        post.type = POST_TYPE_LINK
        domain = domain_from_url(form.link_url.data)
        domain.post_count += 1
        post.domain = domain

        if url_changed:
            if post.image_id:
                remove_old_file(post.image_id)
                post.image_id = None
            valid_extensions = {'.jpg', '.jpeg', '.png', '.gif', '.webp'}
            unused, file_extension = os.path.splitext(form.link_url.data)  # do not use _ here instead of 'unused'
            # this url is a link to an image - generate a thumbnail of it
            if file_extension.lower() in valid_extensions:
                file = url_to_thumbnail_file(form.link_url.data)
                if file:
                    post.image = file
                    db.session.add(file)
            else:
                # check opengraph tags on the page and make a thumbnail if an image is available in the og:image meta tag
                opengraph = opengraph_parse(form.link_url.data)
                if opengraph and opengraph.get('og:image', '') != '':
                    filename = opengraph.get('og:image')
                    valid_extensions = {'.jpg', '.jpeg', '.png', '.gif', '.webp'}
                    unused, file_extension = os.path.splitext(filename)
                    if file_extension.lower() in valid_extensions:
                        file = url_to_thumbnail_file(filename)
                        if file:
                            file.alt_text = opengraph.get('og:title')
                            post.image = file
                            db.session.add(file)

    elif form.type.data == 'image':
        post.title = form.image_title.data
        post.type = POST_TYPE_IMAGE
        uploaded_file = request.files['image_file']
        if uploaded_file and uploaded_file.filename != '':
            if post.image_id:
                remove_old_file(post.image_id)
                post.image_id = None

            # check if this is an allowed type of file
            file_ext = os.path.splitext(uploaded_file.filename)[1]
            if file_ext.lower() not in allowed_extensions or file_ext.lower() != validate_image(uploaded_file.stream):
                abort(400)
            new_filename = gibberish(15)

            # set up the storage directory
            directory = 'app/static/media/posts/' + new_filename[0:2] + '/' + new_filename[2:4]
            ensure_directory_exists(directory)

            # save the file
            final_place = os.path.join(directory, new_filename + file_ext)
            final_place_thumbnail = os.path.join(directory, new_filename + '_thumbnail.webp')
            uploaded_file.save(final_place)

            if file_ext.lower() == '.heic':
                register_heif_opener()

            # resize if necessary
            img = Image.open(final_place)
            img = ImageOps.exif_transpose(img)
            img_width = img.width
            img_height = img.height
            if img.width > 2000 or img.height > 2000:
                img.thumbnail((2000, 2000))
                img.save(final_place)
                img_width = img.width
                img_height = img.height
            # save a second, smaller, version as a thumbnail
            img.thumbnail((256, 256))
            img.save(final_place_thumbnail, format="WebP", quality=93)
            thumbnail_width = img.width
            thumbnail_height = img.height

            file = File(file_path=final_place, file_name=new_filename + file_ext, alt_text=form.image_title.data,
                        width=img_width, height=img_height, thumbnail_width=thumbnail_width,
                        thumbnail_height=thumbnail_height, thumbnail_path=final_place_thumbnail)
            post.image = file
            db.session.add(file)

    elif form.type.data == 'poll':
        ...
    else:
        raise Exception('invalid post type')
    if post.id is None:
        if current_user.reputation > 100:
            postvote = PostVote(user_id=1, author_id=current_user.id, post=post, effect=1.0)
            post.up_votes = 1
            post.score = 1
            post.ranking = 1
            db.session.add(postvote)
        if current_user.reputation < -100:
            postvote = PostVote(user_id=1, author_id=current_user.id, post=post, effect=-1.0)
            post.score = -1
            post.ranking = -1
            db.session.add(postvote)
        post.ranking = post_ranking(post.score, utcnow())
        db.session.add(post)

    g.site.last_active = utcnow()


def remove_old_file(file_id):
    remove_file = File.query.get(file_id)
    remove_file.delete_from_disk()


def save_icon_file(icon_file, directory='communities') -> File:
    # check if this is an allowed type of file
    file_ext = os.path.splitext(icon_file.filename)[1]
    if file_ext.lower() not in allowed_extensions or file_ext.lower() != validate_image(icon_file.stream):
        abort(400)
    new_filename = gibberish(15)

    # set up the storage directory
    directory = f'app/static/media/{directory}/' + new_filename[0:2] + '/' + new_filename[2:4]
    ensure_directory_exists(directory)

    # save the file
    final_place = os.path.join(directory, new_filename + file_ext)
    final_place_thumbnail = os.path.join(directory, new_filename + '_thumbnail.webp')
    icon_file.save(final_place)

    if file_ext.lower() == '.heic':
        register_heif_opener()

    # resize if necessary
    img = Image.open(final_place)
    img = ImageOps.exif_transpose(img)
    img_width = img.width
    img_height = img.height
    if img.width > 250 or img.height > 250:
        img.thumbnail((250, 250))
        img.save(final_place)
        img_width = img.width
        img_height = img.height
    # save a second, smaller, version as a thumbnail
    img.thumbnail((40, 40))
    img.save(final_place_thumbnail, format="WebP", quality=93)
    thumbnail_width = img.width
    thumbnail_height = img.height

    file = File(file_path=final_place, file_name=new_filename + file_ext, alt_text=f'{directory} icon',
                width=img_width, height=img_height, thumbnail_width=thumbnail_width,
                thumbnail_height=thumbnail_height, thumbnail_path=final_place_thumbnail)
    db.session.add(file)
    return file


def save_banner_file(banner_file, directory='communities') -> File:
    # check if this is an allowed type of file
    file_ext = os.path.splitext(banner_file.filename)[1]
    if file_ext.lower() not in allowed_extensions or file_ext.lower() != validate_image(
            banner_file.stream):
        abort(400)
    new_filename = gibberish(15)

    # set up the storage directory
    directory = f'app/static/media/{directory}/' + new_filename[0:2] + '/' + new_filename[2:4]
    ensure_directory_exists(directory)

    # save the file
    final_place = os.path.join(directory, new_filename + file_ext)
    final_place_thumbnail = os.path.join(directory, new_filename + '_thumbnail.webp')
    banner_file.save(final_place)

    if file_ext.lower() == '.heic':
        register_heif_opener()

    # resize if necessary
    img = Image.open(final_place)
    img = ImageOps.exif_transpose(img)
    img_width = img.width
    img_height = img.height
    if img.width > 1600 or img.height > 600:
        img.thumbnail((1600, 600))
        img.save(final_place)
        img_width = img.width
        img_height = img.height

    # save a second, smaller, version as a thumbnail
    img.thumbnail((700, 500))
    img.save(final_place_thumbnail, format="WebP", quality=93)
    thumbnail_width = img.width
    thumbnail_height = img.height

    file = File(file_path=final_place, file_name=new_filename + file_ext, alt_text=f'{directory} banner',
                width=img_width, height=img_height, thumbnail_width=thumbnail_width, thumbnail_height=thumbnail_height)
    db.session.add(file)
    return file


# NB this always signs POSTs as the community so is only suitable for Announce activities
def send_to_remote_instance(instance_id: int, community_id: int, payload):
    if current_app.debug:
        send_to_remote_instance_task(instance_id, community_id, payload)
    else:
        send_to_remote_instance_task.delay(instance_id, community_id, payload)


@celery.task
def send_to_remote_instance_task(instance_id: int, community_id: int, payload):
    community = Community.query.get(community_id)
    if community:
        instance = Instance.query.get(instance_id)
        if post_request(instance.inbox, payload, community.private_key, community.ap_profile_id + '#main-key'):
            instance.last_successful_send = utcnow()
            instance.failures = 0
        else:
            instance.failures += 1
            instance.most_recent_attempt = utcnow()
            instance.start_trying_again = utcnow() + timedelta(seconds=instance.failures ** 4)
            if instance.failures > 2:
                instance.dormant = True
        db.session.commit()