niming_backend/utils/dbhelper.py

from typing import Tuple, Dict, List
from datetime import datetime
import time
import secrets
import hashlib
import os

from flask import make_response, Response, abort, request
from sqlalchemy.orm import sessionmaker
from sqlalchemy import desc, func, update, Engine, text, delete
import pytz

from utils import pgclass, setting_loader, s3helper, logger
from utils.misc import error
from protobuf_files import niming_pb2

class DB:
    _engine = None

    @classmethod
    def __init__(cls, engine):
        cls._engine:Engine = engine

    @classmethod
    def getsession(cls):
        Session = sessionmaker(bind=cls._engine)
        return Session()

db:DB = None


# 上傳單一文章
def solo_article_uploader(content:str, file_list, fmimes:List[str]) -> Tuple[int, str]:
    # loadset
    opt = setting_loader.loadset()
    chk_before_post = opt["Check_Before_Post"]
    
    # hash
    seed = content + str(time.time()) + str(secrets.token_urlsafe(nbytes=16))
    hash = hashlib.sha256(seed.encode()).hexdigest()
    
    # IP
    ip = request.remote_addr
    
    # ig posting (only article)
    if chk_before_post:
        igid = None
    # Go posting
    igid = None
    # Coming Soon...

    # mark
    if chk_before_post: mark = "pending"
    else: mark = "visible"
    
    # posting
    article = pgclass.SQLarticle
    article_mark = pgclass.SQLmark
    article_metadata = pgclass.SQLmeta
    result_id = 0
    try:
        with db.getsession() as session:
            # file processor
            fnlist, err = s3helper.multi_file_uploader(file_list, fmimes)
            if err:
                return 0, ""
            
            # meta processor
            metaa = article_metadata(ip=ip,
                                     igid=igid,
                                     hash=hash)
            session.add(metaa)
            
            # article processor
            posta = article(content=content,
                           hash=hash,
                           file_list=fnlist)
            session.add(posta)
            
            # mark processor
            marka = article_mark(hash=hash,
                                 mark=mark)
            session.add(marka)

            # commit
            session.commit()
            result_id = int(posta.id)
                
            # logger
            logger.logger("newpost", "New post (id=%d): %s"%(result_id, mark))
            
            return result_id, hash
    except Exception as e:
        print(e)
        return 0, ""


# 上傳單一留言
def solo_comment_uploader(content:str, ref:int) -> Tuple[int | str, str]:
    # loadset
    opt = setting_loader.loadset()
    chk_before_post = opt["Check_Before_Post"]
    
    # hash
    seed = content + str(time.time()) + str(secrets.token_urlsafe(nbytes=16))
    hash = hashlib.sha256(seed.encode()).hexdigest()
    sha1 = hashlib.sha1(seed.encode()).hexdigest()
    
    # IP
    ip = request.remote_addr

    # mark
    if chk_before_post: mark = "pending"
    else: mark = "visible"
    
    # posting
    article = pgclass.SQLarticle
    article_mark = pgclass.SQLmark
    try:
        with db.getsession() as session:
            # article processor
            cda = {
                "content":content,
                "ip":ip,
                "hash":hash,
                "created_at":datetime.now(pytz.timezone(os.getenv("TIMEZONE"))),
                "sha1":sha1
            }

            session.execute(
                update(article)
                .where(article.id == ref)
                .values(comment_list=article.comment_list + [cda])
            )
            
            # mark processor
            marka = article_mark(hash=hash,
                                 mark=mark)
            session.add(marka)

            # commit
            session.commit()
                
            # logger
            logger.logger("newcomment", "New comment %s points to %d: %s"%(sha1, ref, mark))
            
            return sha1, hash
    except Exception as e:
        return 0, ""


# role (general) (owner) (admin)
# 獲取單一文章
def solo_article_fetcher(role:str, key) -> Tuple[Dict, int]: # admin, owner, general
    with db.getsession() as session:
        # query
        stmt = "SELECT posts.id AS posts_id, \
                posts.content AS posts_content, \
                posts.file_list AS posts_file_list, \
                article_meta.igid AS article_meta_igid, \
                posts.comment_list AS posts_comment_list, \
                posts.hash AS posts_hash, \
                article_meta.ip AS article_meta_ip \
                FROM posts \
                JOIN mark ON mark.hash = posts.hash \
                JOIN article_meta ON article_meta.hash = posts.hash "
        
        if role == "owner":
            stmt += "WHERE posts.id = :id AND posts.hash = :hash"
            result = session.execute(text(stmt), {"id":key[1], "hash":key[0]})
        elif role == "admin":
            stmt += "WHERE posts.id = :id"
            result = session.execute(text(stmt), {"id":key})
        elif role == "general":
            stmt += "WHERE posts.id = :id AND mark.mark = 'visible'"
            result = session.execute(text(stmt), {"id":key})
        res = result.first()
        if res is None: 
            return abort(404)

        # mapping
        one = {
            "id": res[0],
            "content": res[1],
            "files_hash": res[2],
            "igid": res[3],
        }
        if res[4]:
            one["comments_hash"] = [ c.sha1 for c in res[4] ]
        
        if role == "admin": 
            one["ip"] = res[6]
        if role == "owner" or role == "admin": 
            one["hash"] = res[5]
        
    return one, 200


# role (general) (owner) (admin)
# 獲取單一留言
def solo_comment_fetcher(role:str, key) -> Tuple[Dict, int]: # admin, owner, general
    with db.getsession() as session:
        # query
        stmt = "SELECT posts.id AS parent, c.* \
                FROM posts \
                JOIN mark ON mark.hash = posts.hash \
                JOIN unnest(posts.comment_list) AS c ON 1=1 "
        if role == "general":
            # 對一般用戶，sha1查詢，確保本體可見
            stmt += " WHERE c.sha1 = :key AND mark.mark = 'visible'"
            arta = session.execute(text(stmt), {'key':key}).first()
        elif role == "owner":
            # 對發文者，sha256查詢
            stmt += " WHERE c.hash = :key AND c.sha1 = :sha1"
            arta = session.execute(text(stmt), {'key':key[0], 'sha1':key[1]}).first()
        elif role == "admin":
            # 對管理員，sha1查詢
            stmt += " WHERE c.sha1 = :key"
            arta = session.execute(text(stmt), {'key':key}).first()
        if arta is None:
            return abort(404)

        # mapping
        one = {
            "content": arta[1],
            "sha1": arta[5]
        }
        
        if role == "admin": 
            one["ip"] = arta[2]
        if role == "owner" or role == "admin": 
            one["hash"] = arta[3]
        
    return one, 200


# 獲取文章列表
def multi_article_fetcher(role:str, page:str, count:int) -> Tuple[bytes, int]: # general, admin
    # checker
    if page is None or not page.isdigit(): 
        return abort(400)
    page = int(page)*count

    article = pgclass.SQLarticle
    article_meta = pgclass.SQLmeta
    article_mark = pgclass.SQLmark
    resfn = niming_pb2.FetchResponse()

    with db.getsession() as session:
        # query
        res = session.query(article.id, article.content, article.file_list, article_meta.igid, article.hash, article_meta.ip)
        res = res.join(article_meta, article_meta.hash==article.hash)
        res = res.join(article_mark, article_mark.hash==article.hash)
        if role == "general":
            res = res.filter(article_mark.mark == "visible")
        res = res.order_by(desc(article.id)).offset(page).limit(count).all()
        
        # mapping
        for r in res:
            one = niming_pb2.FetchResponse.Message(
                id = r[0],
                content = r[1],
                files_hash = r[2],
                igid = r[3],
            )
            if role == "admin": # 如果是管理員 多給ip 跟 hash # proto那邊沒支援
                one.hash = r[4]
                one.ip = r[5]
            resfn.posts.append(one)
    
    return resfn.SerializeToString(), 200


# 刪除單一文章
def solo_article_remover(role:str, hash:str=None, id:int=None) -> Tuple[Dict, int]: # admin, owner
    key = None
    if role == "admin": key = id
    elif role == "owner": key = (hash, id)
    
    article = pgclass.SQLarticle
    article_mark = pgclass.SQLmark
    with db.getsession() as session:
        # 獲取本體
        pres = session.query(article.id, article.hash, article_mark.mark, article.file_list).join(article_mark, article_mark.hash==article.hash)
        if role == "admin":
            pres = pres.filter(article.id == key).first()
        elif role == "owner":
            pres = pres.filter(article.id == key[1], article.hash == key[0]).first()
        if pres is None: # 如果本體不存在
            return abort(404)
        
        # 獲取本體的留言們(hash)
        stmt="SELECT c.hash as chash " \
            + "FROM posts, unnest(posts.comment_list) AS c " \
            + "WHERE posts.id = :id"
        cres = session.execute(text(stmt), {'id':pres[0]}).all()
        
        # 刪除本體
        stmt = delete(article).where(article.hash == pres[1])
        session.execute(stmt)
        
        # 刪除 mark (本體 & 留言)
        stmt = delete(article_mark).where(article_mark.hash == pres[1])
        session.execute(stmt)
        for c in cres:
            stmt = delete(article_mark).where(article_mark.hash == c[0])
            session.execute(stmt)
        
        # 刪除檔案
        err = s3helper.multi_file_remover(pres[3])
        if err:
            return abort(500)
        
        session.commit()
    
    # logger
    logger.logger("delpost", "Delete post (id=%d): last_status=%s"
                   %(int(pres[0]), str(pres[2])))
    
    return {"id":pres[0], "mark":pres[2]}, 200


# 刪除單一留言
def solo_comment_remover(role:str, hash:str=None, sha1:str=None) -> Tuple[Dict, int]:
    key = None
    if role == "admin": key = sha1
    elif role == "owner": key = (hash, sha1)
    
    article_mark = pgclass.SQLmark
    with db.getsession() as session:
        # 獲取留言本體
        stmt="SELECT posts.id AS parent, c.sha1, c.hash " \
            + "FROM posts, unnest(posts.comment_list) AS c "
        if role == "admin":
            stmt += "WHERE c.sha1 = :sha1"
            cres = session.execute(text(stmt), {'sha1':key}).first()
        elif role == 'owner':
            stmt += "WHERE c.sha1 = :sha1 AND c.hash = :hash"
            cres = session.execute(text(stmt), {'sha1':key[1], 'hash':key[0]}).first()
        if cres is None: # 如果不存在
            return abort(404)
        
        # 刪除本體
        stmt="UPDATE posts " \
            +"SET comment_list = ARRAY(" \
            +"SELECT c " \
            +"FROM unnest(comment_list) AS c " \
            +"WHERE (c.sha1, c.hash) != (:sha1, :hash)" \
            +")"
        session.execute(text(stmt), {'sha1':cres[1], 'hash':cres[2]})
        
        # 刪除 mark (本體 & 留言)
        mark = session.query(article_mark.mark).filter(article_mark.hash == cres[2])
        stmt = delete(article_mark).where(article_mark.hash == cres[2])
        session.execute(stmt)
        
        session.commit()
    
    logger.logger("delcomment", "Delete comment (sha1=%s): last_status=%s"
                   %(cres[1], str(mark)))
    
    return {"sha1":cres[1], "mark":mark}, 200


# 獲取檔案
def solo_file_fetcher(role:str, fnhash:str) -> Tuple[Response, int]: # general, admin
    with db.getsession() as session:
        arta="SELECT posts.id, posts.hash, mark.mark, f FROM posts " \
            +"JOIN unnest(file_list) AS f ON 1=1 " \
            +"JOIN mark ON posts.hash = mark.hash " \
            +"WHERE f = :fnhash "
        if role == "general":
            arta += "AND mark.mark = 'visible'"
        arta = session.execute(text(arta), {'fnhash':fnhash}).first()
        if arta is None: # 檢查文章本體是否存在/可以閱覽
            return error("File not found"), 404
    
    # fetch file
    f, err = s3helper.solo_file_fetcher(fnhash)
    if err:
        return error("File not found"), 404
    resp = make_response(f["binary"])
    resp.headers.set("Content-Type", f["mime"])
    resp.headers.set("Content-Disposition", f"attachment; filename=file_{fnhash}")
    return resp, 200