import gridfs
import pymongo
from bson import ObjectId
from gridfs import GridFS

DB_USER = "root"
DB_PASS = "sromitdTW569kC#M"
DB_HOST = "116.63.130.34"
DB_PORT = "27018"
CLIENT = pymongo.MongoClient('mongodb://{}:{}@{}:{}'.format(DB_USER, DB_PASS, DB_HOST, DB_PORT))


def FIND_FILE(file_db, file_bucket, file_id):
    """
    读取一个文件
    Parameters:
        file_db: 数据库
        file_bucket: 存储桶
        file_id: 文件id
    Returns:
        data 文件二进制
    """
    try:
        # 实例化一个文件存储器
        gfs = GridFS(CLIENT[file_db], collection=file_bucket)
        # 二进制读取文件
        data_stream = gfs.get(ObjectId(file_id)).read()
        # 返回文件二进制流
        return data_stream
    except gridfs.errors.NoFile:
        return False