c# - 给定物理路径，Server.MapPath 中需要虚拟路径

Question

I trying to change my directory which in my local c disk, but where errors says in the title. Is there any way aside from using Server.MapPath?. I'm using a ZipOutputStream nuget package.

I want to locate my directory in C: instead inside the project folder.

 public FileResult DownloadZipFileSig(string FileId){ 
                   
  var fileName = "FilesDL".zip";
  var tempOutPutPath = Server.MapPath(Url.Content("C:/Users/SDILAP2/Desktop/ID_Esig_Files")) + fileName;
              
            
                     using (ZipOutputStream s = new ZipOutputStream(System.IO.File.Create(tempOutPutPath)))
                     {
                        s.SetLevel(9); 
            
                        byte[] buffer = new byte[4096];
            
                        List<string> stringList = FileId.Split(',').ToList();
            
                        List<string> tempList = new List<string>();
            
                        foreach (string str in stringList)
                        {
            
                           if (System.IO.File.Exists(Server.MapPath("C:/Users/SDILAP2/Desktop/ID_Esig_Files/" + str + ".jpeg")))
                           {
                              tempList.Add(Server.MapPath("C:/Users/SDILAP2/Desktop/ID_Esig_Files/" + str + ".jpeg"));
            
                           }
          
            
                        }
            
                        stringList = tempList;
            
            
                        for (int i = 0; i < stringList.Count; i++)
                        {
                           ZipEntry entry = new ZipEntry(Path.GetFileName(stringList[i]));
                           entry.DateTime = DateTime.Now;
                           entry.IsUnicodeText = true;
                           s.PutNextEntry(entry);
            
                           using (FileStream fs = System.IO.File.OpenRead(stringList[i]))
                           {
                              int sourceBytes;
                              do
                              {
                                 sourceBytes = fs.Read(buffer, 0, buffer.Length);
                                 s.Write(buffer, 0, sourceBytes);
                              } while (sourceBytes > 0);
                           }
                        }
                        s.Finish();
                        s.Flush();
                        s.Close();
            
                     }
            
                     return File(finalResult, "application/zip", fileName);
            
                  }

Answer 1

You might be not quite grasping how web URL's work, and how server.mappath() is to be used.

Web users:

When you have a web based url, then all html markup in a page, or even user supplied URL's are so called web based.

So, if you have a folder from the root of your web site say called MyUpLoads

Then that is just a folder in the web site path names.

eg:

www.mywebsite/UpLoadFiles/cat.jpg

And if you write html markup, then you can and could provide a URL to the above picute, or say with a html image control, you could set the ImageURL or "source" (src) to that file.

And if you using IIS (and not IIS express), then of course you can add what is called a virutal folder. Say some big server drive on ANOHTER computer on the same network.

So, that virtual folder could be anywhere on your network, and of course AGAIN for web HTML, or web URL's, again you use this format:

www.mysite/MassiveFolder/info.pdf

or maybe

 localhost:5403/MyUpLoads/cat.jpg

However, in code behind?

ANY code behind (c# or vb.net) ALWAYS uses plane jane WINDOWS file paths. These are valid full windows file names.

That means that code behind is 100% free to open/read/use/see/play with ANY file on the computer, and any file even on the computer network.

So when you use

server.mapPath("localhost:5403/MyUpLoads/cat.jpg")

Then the above is translated into a local plane jane DOS/WINDOWS file path!!!!

The above may well become

C:\Users\AlbertKallal\source\repos\CSharpWebApp\MyUpLoads\cat.jpg

So keep in mind:

web urls - HTML/asp markup in a page = web based syntax/path.

computer path: plane jane full path names like all windows software.

So, in your case?

 var fileName = "FilesDL".zip";
  var tempOutPutPath = @"C:/Users/SDILAP2/Desktop/ID_Esig_Files")) + fileName;

So you don't need nor want to user server.mappath, since that is ONLY for a given HTML or web based URL that you want to translate into the local computer file path system.

Since your path name(s) are already in that format, then no need is required.

in fact, keep in mind that you can use this fact to your advantage.

ANY folder (or a vitural folder) will appear in your valid URL's and path names (web based).

However, you might have some pdf's, or sensitive documents. So move that folder OUT of the root or web project folders.

Now, no valid URL's exist, or are even allowed.

However, code behind? It can run, see and use ANY file on your computer - and you use code behind to get those files - but the web site, web side of things has NO ability to use or see or get those files. And you can still do things like say provide a download button, but your code behind can fetch the file, read it and pump it out to the end user (stream the file).

So you only need (have) to use the Server.MapPath function WHEN the URL comes from the web site or html markup. This will translate that web based URL into a regular good old fashion full qualified windows file path name.

However, if you already have that full windows path name, then no URL translate to windows file path is required.

So, for the most part, your code behind can look at, see, grab and play with files on the server. Web users, or web based urls MUST be part of the folders in the web site, but no such restrictions exist for the code behind.

Now, when the code is deployed to a web server, often some file security rights on in place, but as a general rule, that web code behind is NOT limited nor restricted to JUST folders in the web site. Those valued URL's are a restriction for the users and web browsers, and as noted, often a folder outside of the web site is used for security purposes, since no possible valid web based paths can use/see or even resolve to file outside of the root starting folder of the web site.

So for those existing files, you don't need server.mappath.