ExternalAPI_NET8/Common/MongoDB/MongoDBHelper.cs

using System.Linq.Expressions;
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using MongoDB.Driver;
using Web.Core.Common.Helper;
using Web.Core.Model.Entity;

namespace Web.Core.Common.MongoDB;

public class MongoDBHelper<T>:IMongoDBHelper<T> where T : MDBBaseEntity
{
    private readonly IMongoDatabase database;
    public MongoDBHelper()
    {
        var url = new MongoUrl(AppSettings.GetConnectionString("MongoDB"));
        MongoClientSettings mcs = MongoClientSettings.FromUrl(url);
        mcs.MaxConnectionLifeTime = TimeSpan.FromMilliseconds(1000); 
        var client = new MongoClient(mcs);
        database = client.GetDatabase(url.DatabaseName);
    }
    
    private IMongoCollection<T> GetColletion(string collName)
    {
        return database.GetCollection<T>(collName);
    }
    
 #region 查询
        /// <summary>
        /// 查询，复杂查询直接用Linq处理
        /// </summary>
        /// <param name="collName">集合名称</param>
        /// <returns>要查询的对象</returns>
        private IQueryable<T> GetQueryable(string collName)
        {
            var coll = GetColletion(collName);
            return coll.AsQueryable<T>();
        }
        /// <summary>
        /// 根据条件表达式返回可查询的记录源
        /// </summary>
        /// <param name="query">查询条件</param>
        /// <param name="sortPropertyName">排序表达式</param>
        /// <param name="isDescending">如果为true则为降序，否则为升序</param>
        /// <returns></returns>
        private  IFindFluent<T, T> GetQueryable(string collName, FilterDefinition<T> query, string sortPropertyName, bool isDescending = true)
        {
            IMongoCollection<T> collection = GetColletion(collName);
            IFindFluent<T, T> queryable = collection.Find(query);
            var sort = isDescending ? Builders<T>.Sort.Descending(sortPropertyName) : Builders<T>.Sort.Ascending(sortPropertyName);
            return queryable.Sort(sort);
        }
        /// <summary>
        /// 根据条件表达式返回可查询的记录源
        /// </summary>
        /// <param name="match">查询条件</param>
        /// <param name="orderByProperty">排序表达式</param>
        /// <param name="isDescending">如果为true则为降序，否则为升序</param>
        /// <returns></returns>
        private IQueryable<T> GetQueryable<TKey>(string collName, Expression<Func<T, bool>> match, Expression<Func<T, TKey>> orderByProperty, bool isDescending = true)
        {
            IMongoCollection<T> collection = GetColletion(collName);
            IQueryable<T> query = collection.AsQueryable();
            if (match != null)
            {
                query = query.Where(match);
            }
            if (orderByProperty != null)
            {
                query = isDescending ? query.OrderByDescending(orderByProperty) : query.OrderBy(orderByProperty);
            }
            else
            {
                // query = query.OrderBy(sortPropertyName, isDescending);
            }
            return query;
        }

        
        /// <summary>
        /// 根据条件查询数据库,并返回对象集合
        /// </summary>
        /// <param name="match">条件表达式</param>
        /// <param name="sortPropertyName">排序字段</param>
        /// <param name="isDescending">如果为true则为降序，否则为升序</param>
        /// <returns></returns>
        public IList<T> Find(string collName, Expression<Func<T, bool>> match, string sortPropertyName, bool isDescending = true)
        {
            return GetQueryable(collName, match, sortPropertyName, isDescending).ToList();
        }
        /// <summary>
        /// 根据条件查询数据库,并返回对象集合
        /// </summary>
        /// <param name="query">条件表达式</param>
        /// <param name="sortPropertyName">排序字段</param>
        /// <param name="isDescending">如果为true则为降序，否则为升序</param>
        /// <returns></returns>
        public IList<T> Find(string collName, FilterDefinition<T> query, string sortPropertyName, bool isDescending = true)
        {
            return GetQueryable(collName, query, sortPropertyName, isDescending).ToList();
        }
        
        /// <summary>
        /// 根据条件表达式返回可查询的记录源（异步方法）
        /// </summary>
        /// <param name="collName"></param>
        /// <param name="query"></param>
        /// <returns></returns>
        public async Task<IList<T>> FindAsync(string collName, FilterDefinition<T> query)
        {
            IMongoCollection<T> collection = GetColletion(collName);
            var cursor = await collection.FindAsync(query);
            return await cursor.ToListAsync(); 
        }
        
        /// <summary>
        /// 根据条件查询数据库,并返回对象集合
        /// </summary>
        /// <param name="match">条件表达式</param>
        /// <param name="orderByProperty">排序表达式</param>
        /// <param name="isDescending">如果为true则为降序，否则为升序</param>
        /// <returns></returns>
        public IList<T> Find<TKey>(string collName, Expression<Func<T, bool>> match, Expression<Func<T, TKey>> orderByProperty, bool isDescending = true)
        {
            return GetQueryable<TKey>(collName, match, orderByProperty, isDescending).ToList();
        }
        /// <summary>
        /// 根据条件查询数据库,如果存在返回第一个对象
        /// </summary>
        /// <param name="filter">条件表达式</param>
        /// <returns>存在则返回指定的第一个对象,否则返回默认值</returns>
        public T FindSingle(string collName, FilterDefinition<T> filter)
        {
            var coll = GetColletion(collName);
            return coll.Find(filter).FirstOrDefault();
        }
        
        #endregion
    
    
}