MongoDB 使用GridFS保存文件

上篇文章说了一下怎么试用MongoDB来做replication，但是我是通过BSON Object来保存文件，这有个局限，就是如果文件超过4m就会抛出超过最大文件的异常。

根据官网介绍，BSON objects in MongoDB are limited to 4MB in size. http://www.mongodb.org/display/DOCS/GridFS

因此重新写了那个操作类，使用GridFS来保存文件，代码很简单，但开始接触弄了比较长时间，有一个问题一直解决不了，我希望自己生成一个Guid的 _id 而不是mongodb生成的_id，但是一直解决不了，希望哪个高手看到指点一下，谢谢！

这个是使用Mongodb官网提供的客户端写的：

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using MongoDB.Driver;
using MongoDB.Driver.Builders;
using MongoDB.Bson;
using MongoDB.Driver.GridFS;

namespace FileUtility
{
public class DocUtility
{
private string connStr = "";
public string ConnStr
{
get
{
if (string.IsNullOrEmpty(connStr))
{
throw new ArgumentNullException("Connection string did not specify!");
}
return connStr;
}
}
public DocUtility()
{
connStr = System.Configuration.ConfigurationManager.AppSettings["FileDb"];
}

public DocUtility(string connectionString)
{
this.connStr = connectionString;
}

/// <summary>
/// add a document to mongodb
/// </summary>
/// <param name="content">document bytes array</param>
/// <returns>the unique identity filename in mongodb</returns>
public string AddDoc(byte[] content)
{
MongoServer server = MongoServer.Create(this.ConnStr);
try
{
string filename = Guid.NewGuid().ToString();
server.Connect();
MongoDatabase db = server.GetDatabase("ecDocs");
MongoGridFS fs = new MongoGridFS(db, new MongoGridFSSettings() { Root="ecDocs" });
MongoGridFSFileInfo info = new MongoGridFSFileInfo(fs, filename);
using (MongoGridFSStream gfs = info.Create())
{
gfs.Write(content, 0, content.Length);
}
return filename;
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (server != null)
server.Disconnect();
}
}

/// <summary>
/// delete doc from mongodb
/// </summary>
/// <param name="filename">the unique identity filename</param>
public string DeleteDoc(string filename)
{
MongoServer server = MongoServer.Create(this.ConnStr);
try
{
server.Connect();
MongoDatabase db = server.GetDatabase("ecDocs");
MongoGridFS fs = new MongoGridFS(db, new MongoGridFSSettings() { Root = "ecDocs" });
fs.Delete(filename);
return filename;
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (server != null)
server.Disconnect();
}
}

/// <summary>
/// get document bytes array from mongodb
/// </summary>
/// <param name="filename">unique filename</param>
/// <returns>bytes array</returns>
public byte[] GetDoc(string filename)
{
MongoServer server = MongoServer.Create(this.ConnStr);
try
{
server.Connect();
MongoDatabase db = server.GetDatabase("ecDocs");
MongoGridFS fs = new MongoGridFS(db,new MongoGridFSSettings() { Root="ecDocs" });
byte[] bytes = null;
using (MongoGridFSStream gfs = fs.Open(filename, FileMode.Open))
{
bytes = new byte[gfs.Length];
gfs.Read(bytes, 0, bytes.Length);
}
return bytes;
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (server != null)
server.Disconnect();
}
}
}
}

下面这个类是使用Samus的客户端：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using MongoDB;
using MongoDB.GridFS;

namespace FileUtilitySamus
{
public class DocUtility
{
private string connStr = "";
public string ConnStr
{
get
{
if (string.IsNullOrEmpty(connStr))
{
throw new ArgumentNullException("Connection string did not specify!");
}
return connStr;
}
}
public DocUtility()
{
connStr = System.Configuration.ConfigurationManager.AppSettings["FileDb"];
}

public DocUtility(string connectionString)
{
this.connStr = connectionString;
}

/// <summary>
/// add a document to mongodb
/// </summary>
/// <param name="content">document bytes array</param>
/// <returns>the unique identity filename in mongodb</returns>
public string AddDoc(byte[] content)
{
using (Mongo mongo = new Mongo(this.ConnStr))
{
try
{
string filename = Guid.NewGuid().ToString();

mongo.Connect();
IMongoDatabase db = mongo.GetDatabase("ecDoc");

GridFile fs = new GridFile(db, "ecDoc");
GridFileInfo info = new GridFileInfo(db, "ecDoc", filename);
using (GridFileStream gfs = info.Create())
{
gfs.Write(content, 0, content.Length);
}

return filename;
}
catch (Exception ex)
{
throw ex;
}
}
}

/// <summary>
/// delete doc from mongodb
/// </summary>
/// <param name="filename">the unique identity filename</param>
public void DeleteDoc(string filename)
{
using (Mongo mongo = new Mongo(this.ConnStr))
{
try
{
mongo.Connect();
IMongoDatabase db = mongo.GetDatabase("ecDoc");

GridFile fs = new GridFile(db, "ecDoc");

fs.Delete(new Document("filename", filename));

}
catch (Exception ex)
{
throw ex;
}
}
}

/// <summary>
/// get document bytes array from mongodb
/// </summary>
/// <param name="filename">unique filename</param>
/// <returns>bytes array</returns>
public byte[] GetDoc(string filename)
{
using (Mongo mongo = new Mongo(this.ConnStr))
{
try
{
mongo.Connect();
IMongoDatabase db = mongo.GetDatabase("ecDoc");
GridFile fs = new GridFile(db, "ecDoc");
GridFileStream gfs = fs.OpenRead(filename);
byte[] bytes = new byte[gfs.Length];
gfs.Read(bytes, 0, bytes.Length);
return bytes;
}
catch (Exception ex)
{
if (ex.GetType() == typeof(System.IO.DirectoryNotFoundException))
throw new System.IO.FileNotFoundException("File not found :" + filename);
else
throw ex;
}
}
}
}
}

不知道两个客户端的性能相比如何？希望测试过的同学分享一下。