c＃Web API在本地可用，但发布后在Azure中不起作用

Question

I got below error. I am trying to implement download WEB API in C# which downloads the blob to file from azure blob storage.

I have tried debugging mode on visual studio but it it doesn't work and return errors when tested locally only get that error on deployment. i'm guessing it might be the file path but i don't know to be honest.

Internal Server Error 500.

[RoutePrefix("api/download")]
[EnableCors(origins: "*", headers: "*", methods: "*")]
public class DownloadController : ApiController
{
    private ggContext db = new ggContext();
    private const string Container = "ggblobcontainer";
    [HttpGet]
    public HttpResponseMessage GetFile(int audioid)
    {
        //get the object storing the audio 
        Someobject zzz = db.Meetings.Find(audioid);
        //get the filename from the object 
        string fileName = zzz.GetFileName();
        //account information from web.config 
        var accountName = ConfigurationManager.AppSettings["storage:account:name"];
        var accountKey = ConfigurationManager.AppSettings["storage:account:key"];
        var storageAccount = new CloudStorageAccount(new StorageCredentials(accountName, accountKey), true);
        //create blob client from account
        CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();
        //get the container with the blobs storing the audio
        CloudBlobContainer audioContainer = blobClient.GetContainerReference(Container);
        //get the specific blob with the filename from object
        CloudBlockBlob blockBlob = audioContainer.GetBlockBlobReference(fileName);
        //if the blob is null error response
        if (blockBlob == null)
        {
            return Request.CreateErrorResponse(HttpStatusCode.NotFound, "blob with the file name " + fileName + " does not exist in " + Container);
        }
        try
        {
            //cause audio storage name on azure has "" eg. "sick audio file - why is it wrong [LYRICS].mp3" with quotations
            string regexSearch = new string(Path.GetInvalidFileNameChars()) + new string(Path.GetInvalidPathChars());
            Regex r = new Regex(string.Format("[{0}]", Regex.Escape(regexSearch)));
            //replace illegal chars with nothing in case replace the . for .mp3 
            string CleanFileName = r.Replace(fileName, "");
            // download to desktop
            string path = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
            //change it to fileName not dragon little bits 
            string gg = Path.Combine(path, CleanFileName);
            blockBlob.DownloadToFile(gg, FileMode.Create);
        }
        catch (Exception e)
        {
            throw e;
        }
        return Request.CreateResponse(HttpStatusCode.OK, fileName + " was downloaded succesfully");
    }
}

Answer 1

As mentioned above, Environment.GetFolderPath(Environment.SpecialFolder.Desktop) wont work on server environment. So you have to try something like:

string gg = Path.Combine(Server.MapPath("~\SomeDirectoryName"), CleanFileName)

Hope this would help.