FastDFS 使用经验分享

不念不忘少年蓝@ 2022-08-02 02:20 197阅读 0赞

## 经验一：[FastDFS][]文件下载恢复原始文件名 ##

### 应用背景 ###

文件被上传到Fast[DFS][]后Storage服务端将返回的文件索引（FID），其中文件名是根据FastDFS自定义规则重新生成的，而不是原始文件名，例如： group2/M00/00/89/eQ6h3FKJf\_PRl8p4AUz4wO8tqaA688.apk

使用http下载时如不加处理，显示给用户的文件名会是这样的eQ6h3FKJf\_PRl8p4AUz4wO8tqaA688.apk，这样的用户体验很不好。由于FastDFS不会存储原始文件名，也没有提供恢复原始文件名的方法，所以需要应用系统自己想办法恢复原始文件名。

### 解决方法 ###

通过在项目中多次尝试，找到一种较简单的实现方法，实现过程如下：

一. 应用系统在上传文件到FastDFS成功时将原始文件名和“文件索引（FID）”保存下来（例如：保存到数据库）。

二. 用户点击下载的时用[Nginx][]的域名和FID拼出url，然后在url后面增加一个参数，指定原始文件名。例如：http://121.14.161.48:9030/group2/M00/00/89/eQ6h3FKJf\_PRl8p4AUz4wO8tqaA688.apk?attname=filename.apk

三. 在Nginx上进行如下配置，这样Nginx就会截获url中的参数attname，在Http响应头里面加上字段 Content-Disposition “attachment;filename=$arg\_attname”。

四. 浏览器发现响应头里面有Content-Disposition “attachment;filename=$arg\_attname”时，就会把文件名显示成filename指定的名称。

完整的请求和响应消息如下：

请求包：

<table style="border-spacing:0px; border:0px!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; border-collapse:collapse!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; background:none!important"> 
 <tbody style="border:0px!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; background:none!important"> 
  <tr style="border:0px!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; background:none!important"> 
   <td style="border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-style:none!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px 0px 0px 0.5em!important; vertical-align:top!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(185,189,182)!important; white-space:pre!important; background:none!important"> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important">User-Agent:Mozilla/</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">5.0</code> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important"> (Windows NT </code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">6.1</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important">) AppleWebKit/</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">537.36</code> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important"> (KHTML, like Gecko) Chrome/</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">31.0</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important">.</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">1650.57</code> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important"> Safari/</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">537.36</code></td> 
  </tr> 
 </tbody> 
</table>

返回包：

<table style="border-spacing:0px; border:0px!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; border-collapse:collapse!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; background:none!important"> 
 <tbody style="border:0px!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; background:none!important"> 
  <tr style="border:0px!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; background:none!important"> 
   <td style="border-top-width:0px!important; border-right-width:0px!important; border-bottom-width:0px!important; border-left-style:none!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px 0px 0px 0.5em!important; vertical-align:top!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(185,189,182)!important; white-space:pre!important; background:none!important"> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important">Last-Modified:Mon, </code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">18</code> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important"> Nov </code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">2013</code> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important"> 02</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important">:</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">48</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important">:</code><code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(0,153,0)!important; background:none!important">19</code> <code style="border:0px!important; font-family:Consolas,'Bitstream Vera Sans Mono','Courier New',Courier,monospace!important; font-size:1em!important; margin:0px!important; outline:0px!important; padding:0px!important; vertical-align:baseline!important; float:none!important; position:static!important; left:auto!important; top:auto!important; right:auto!important; bottom:auto!important; height:auto!important; width:auto!important; line-height:1.1em!important; min-height:inherit!important; color:rgb(211,211,211)!important; background:none!important"> GMT</code></td> 
  </tr> 
 </tbody> 
</table>

## 经验二：从文件的使用技巧 ##

### 应用背景 ###

使用FastDFS存储一个图片的多个分辨率的备份时，希望只记录源图的FID，并能将其它分辨率的图片与源图关联。可以使用从文件方法。

### 解决方法 ###

名词注解：主从文件是指文件ID有关联的文件，一个主文件可以对应多个从文件。

*  主文件ID = 主文件名 + 主文件扩展名
 *  从文件ID = 主文件名 + 从文件后缀名 + 从文件扩展名

以本场景为例：主文件为原始图片，从文件为该图片的一张或多张缩略图。

流程说明：

1.  先上传主文件（即：原文件），得到主文件FID
2.  然后上传从文件（即：缩略图），指定主文件FID和从文件后缀名，上传后得到从文件FID。

java伪代码，如下：

上面代码运行后打印的文件Id为：

*  主文件：group1/M00/00/00/wKhbylJx1zkIAAAAAAApPcQL87AAAAAAQCmDxUAAClV522.png
 *  从文件：group1/M00/00/00/wKhbylJx1zkIAAAAAAApPcQL87AAAAAAQCmDxUAAClV522\_120x120.png

注意：

FastDFS中的主从文件只是在文件ID上有联系。FastDFS server端没有记录主从文件对应关系，因此删除主文件，FastDFS不会自动删除从文件。删除主文件后，从文件的级联删除，需要由应用端来实现。

转自：http://tech.uc.cn/?p=2579

[FastDFS]: http://www.ttlsa.com/fastdfs/
[DFS]: http://www.ttlsa.com/dfs/
[Nginx]: http://www.ttlsa.com/nginx/