Develop Reference

Why can't I access static files that I add programmatically from a POST request?

I'm attempting to make a basic .NET API for managing a collection of media (images and videos).
I have configured the webroot to be a folder called "site", and within that folder is a folder called "media" where these files are stored. I can access a test media file that is saved in /site/media/Smush.jpg by loading https://localhost:5001/site/media/smush.jpg - this serves the image as expected.
I have created a method that receives a POST request containing form data from my frontend, and this method saves the file to the webroot using a filestream, code below:
[HttpPost]
[Route("/media/add")]
public async Task<HttpResponseMessage> MediaAdd()
{
try
{
//get the form
var form = HttpContext.Request.Form;
//if there's a route, add it into the filepath, otherwise leave it out and have the filepath go straight to media (this prevents an exception if route is blank)
string filePath = form["route"] == "" ? Path.Combine(_hostingEnvironment.WebRootPath, "media") : Path.Combine(_hostingEnvironment.WebRootPath, "media", form["route"]);
//get the first (should be only) image - DO WE WANT TO BE ABLE TO ADD MULTIPLE IMAGES? PROBABLY TBH
IFormFile image = form.Files.First();
if (image.Length > 0)
{
//check the directory exists - create it if not
if (!Directory.Exists(filePath)) {
Directory.CreateDirectory(filePath);
}
using (Stream fileStream = new FileStream(Path.Combine(filePath, form["filename"]), FileMode.Create))
{
await image.CopyToAsync(fileStream);
return new HttpResponseMessage(HttpStatusCode.OK);
}
}
else {
return new HttpResponseMessage(HttpStatusCode.BadRequest);
}
}
catch (Exception e)
{
return new HttpResponseMessage(HttpStatusCode.BadRequest);
}
}
My frontend submits a route, filename and the media file, and this is used to save the image. This all works fine; I can submit an image with the path "test" and the name "test.jpg", and the API correctly stores the file at /site/media/test/test.jpg. I can view the file in the solution and see a preview of the image, as with Smush.jpg.
However, attempting to load https://localhost:5001/site/media/test/test.jpg results in a 404. Why is this the case? Can I not add files into the webroot through code and have them be accessible as static files as if I added them to the solution in my IDE? Are there any alternative ways of handling this?
I am using .NET 5.0, and have
app.UseStaticFiles(); in Configure() in Startup.cs.
Sorry if this is a duplicate, but I couldn't find anything else like this.
EDIT:
On checking things again, it seems like rather than my files being at https://localhost:5001/site/media, they are simply in https://localhost:5001/media. I am not sure how I was able to access Smush.jpg at https://localhost:5001/site/media/Smush.jpg before.
It seems as though the webroot is not included as part of a URL to access files within it.
As it is now, I have got what I was looking for it to do.

Well first a security concern as also #Heinzi pointed out...
string filePath = form["route"] == "" ? Path.Combine(_hostingEnvironment.WebRootPath, "media") : Path.Combine(_hostingEnvironment.WebRootPath, "media", form["route"]);
What if the user sends form.route == "../../" and instead of image he updates the appsettings.json file ?
Check this out and have that in mind if you're planing to release this code to a production environment and make sure you only accept image files.
On the other hand if you are serving static files from a folder different to wwwroot please use this configuration

Why the 404
It makes sense. You are under the controller/action paths. Going under the site url the engine does the following:
When you request https://localhost:5001/site/media/test/test.jpg the code tries to find the media controller and the test action. It is not looking for static files on the filesystem. Since there is no such controller/action pairs, it will not find anything and thus return 404 not found.
If you saved the files in https://localhost:5001/static/media/test.jpg outside of the mapped routes, you would be able to access it.
Look inside your code for:
MapHttpRoute
Which is used to configure how to identify controller actions which are not decorated with the [Route] attribute.
Security concern
When you want to upload a file, you should consider a better solution and not one that accesses directly your filesystem.
Possible options:
Blob storage on the cloud
Database blobs
Don't forget to sanitize the input with an antivirs or some similar solution.

Get data in file without indicating a particular filepath

I am tasked to create a web service API where for an example, when an URL http://localhost:12345/api/filereader/data.txt is entered in the web browser, the data which is in data.txt file has to be displayed in the web page. I am able to do it if I know the filepath of data.txt.
However another requirement is that I am not supposed to indicate the filepath (in my code) as the scenario is, user is supposed to be able to use the URL API and input the .txt file name as a parameter (from whichever computer/server they are using) to get the data of what is in the .txt file that they have indicated. Therefore there should not be any physical path in my code. Is it possible to achieve that?
Here is the code that I have tried (with filepath):
ReaderController.cs
[ResponseType(typeof(string))]
public IHttpActionResult Get(String FileName)
{
try
{
string fileName = FileName;
string path = "C:\\Users\\attsuap1\\Desktop\\" + fileName;
string result = File.ReadAllText(path);
var resultDTO = JsonConvert.DeserializeObject(result);
return Ok(resultDTO);
}
catch
{
var result = "File does not exist";
return Ok(new { ErrorMessage = result });
}
}
How do I edit this code to get what I want?

You are asking to load a file from a user device from your server. That is just not possible for security purposes (imagine what would happen if you could).
The only way to get access to a file from the user, is by letting the user send it using some sort of upload form or control. The posted data can be used by your server then.

Not allowed to load local resource from App_Data folder

I need to server a larger amount of Pdf's which require authorisation in order to be able to download.
I have read that it is advisable to place them in the App_Data folder.
I have created three folders in the App_Data folder:
> SetOne
> SetTwo
> SetThree
I need to pass these files to my view.
Controller
var files = Directory.EnumerateFiles(Server.MapPath("~/App_Data/SetOne"));
return View(files);
View
<ul>
#foreach (var fullPath in Model)
{
var fileName = Path.GetFileName(fullPath);
var downloadPath = #Path.GetDirectoryName(fullPath) + "\\" + #fileName;
<li>#fileName</li>
}
</ul>
Using the above code, I am able to list the contents of the SetOne folder in an unordered list, however when I attempt to view one of the Pdf's I see:
Not allowed to load local resource:
file:///B:/Development/MyProject/MyProject.Web/App_Data/SetOne/sampleOne.pdf
How can I allow the application to give access to these files?
edit
I've also tried creating a new folder called Pdfs and moving the documents to this, however I get the same error message when I view in chrome dev tools.
Do I need to implement a Http Handler for this task?

Your approach is OK for WinForms application but shouldn't work for Web. downloadPath should contain the Url but not the physical path on the file (like some.com/pdfs/1.pdf)
You could use Server.MapPath for this case

How to download files from OneDrive

I am looking to download my files in public folder from One Drive, but it doesn't download the files.
Here is the scenario:
In public folder I have another folder with multiple files in it and is accessible widely.
for test purpose I have shared all the files in public folder (I don't if it's proper way of sharing it).
The following links are provided for me to download the file:
From shared folder link https://onedrive.live.com/redir?resid=DBBC281099F4FE69!646&authkey=!AGRCGuw8Y2_p9mA&ithint=folder%2c.mp3
From public folder link https://onedrive.live.com/redir?resid=DBBC281099F4FE69%21646
Direct link http://1drv.ms/1z9XlW6 -
I am using BackgroundTransferRequest to download the file using below code:
string filePathToDownload = string.Empty, fileName = "111.mp3";
filePathToDownload = "http://1drv.ms/1z9XlW6";
Uri transferUri = new Uri(Uri.EscapeUriString(filePathToDownload), UriKind.RelativeOrAbsolute);
BackgroundTransferRequest transferRequest = new BackgroundTransferRequest(transferUri);
transferRequest.Method = "GET";
transferRequest.TransferPreferences = TransferPreferences.AllowCellularAndBattery;
Uri downloadUri = new Uri(DataSource.TEMPDOWNLOADLOCATION + fileName, UriKind.RelativeOrAbsolute);
transferRequest.DownloadLocation = downloadUri;
transferRequest.Tag = fileName;
The file is 300Kb, but this only downloads 6 Kb.
How can I directly download the file from the links above (any of them)?
thanks!

If you replace the word redir with download in the url you get the raw file instead of the webpage i.e.
https://onedrive.live.com/download?resid=DBBC281099F4FE69%21646

Basically, you can't. Those links are links to the web content that shows the files you have shared. If your scenario doesn't mind asking the user to log in to OneDrive, then you can use the Live SDK to access these files.
To access your public folder from Live SDK, you need to either use Live SDK to get the folder-id for your public folder, or convert the IDs in the URL you copied into the format the Live SDK uses:
folder.<user-id>.<folder-resid>
Where is the part of before the !. In general you shouldn't construct an ID, since it's possible the IDs will change in the future, and instead you should retrieve the ID from the service. However, with the URL you pasted the ID would be:
folder.DBBC281099F4FE69.DBBC281099F4FE69!646
Which will allow you to call
https://apis.live.net:443/v5.0/folder.DBBC281099F4FE69.DBBC281099F4FE69!646/files?access_token=<valid_token>
and retrieve the IDs for the individual files, which you can then download via Live SDK following these details: http://msdn.microsoft.com/en-US/library/dn659726.aspx#download_a_file

For those who are still looking for a response to that question.
The easiest way to find the file path is to go to One Drive on the web and right-click on the file that we want and select Embed. Τhen on the right we see the info window to integrate our file into a page. Inside the iframe is the source of the file. Then we have to replace the word embed with the word download and that's it.

Try something like this
//we first need the file id
string id = string.Empty;
//we need to get all of the filenames stored in the root of the skydrive account
LiveOperationResult result = await this.client.GetAsync("me/skydrive/files");
//lets make a list of all these filenames
List<object> items = result.Result["data"] as List<object>;
//for every filename, check if it is what we want, in this case "sample.txt"
//if it is what we want, get the id and save it to out already defined id value
foreach (object item in items)
{
IDictionary<string, object> file = item as IDictionary<string, object>;
if (file["name"].ToString() == "sample.txt")
{
id = file["id"].ToString();
}
}
//to download the file we need to use the id + "/content"
LiveDownloadOperationResult result2 = await client.DownloadAsync(string.Format("{0}/content", id));
//once the file had downloaded, lets copy it to IsolatedStorage
Stream stream = result2.Stream;
using (IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication())
{
using (IsolatedStorageFileStream fileToSave = storage.OpenFile("sample.txt", FileMode.Create, FileAccess.ReadWrite))
{
stream.CopyTo(fileToSave);
stream.Flush();
stream.Close();
}
}
here client is the object of LiveConnectClient class.
Import
using Microsoft.Live;
using Microsoft.Live.Controls;
Here is use txt file as an example. Go through this example:http://www.baileystein.com/2013/10/20/skydrive-how-to-upload-and-download-a-text-file-on-wp8/

Using FileUpload C#

I have a project where I get a list of file location strings that I want to save locally. I want to use a FileUploader to do so. I am trying something like this so far:
FileUpload filesaver = new FileUpload();
//Iterate over each files (InputFiles is a linked list of file locations)
foreach (string File in InputFiles)
{
//Get file
Stream fileLoaded = OpenFile(File);
filesaver.FileContent = fileLoaded;
//Save file
filesaver.SaveAs(DownloadLocation);
//Code...}
The problem is that filesaver.FileContent = fileLoaded; is not a valid call (FileContent is read only).
How would I be able to get the file to the file loader so that I can save it if I have a string of that file location?
Edit I am using the FileUpload Class

The ASP.NET FileUploader has the client side send the file to the server side. It does not send a file path as a string, so there is no way to intercept the file path and "upload" on the server side. if that is your intent, you are not going to find a way to get there from here.
If you want to save the actual file binary bits once it gets to the server, there are plenty of examples out there that persist the data to databases or file system.
If you are trying to get paths as strings, the file uploader is not your best choice, but note that the file path strings, if they are local to the client, are of no use on the server side.

You can just use:
If (filesaver.HasFile)
{
filesaver.SaveAs("C:\YourFilePath\" & filesaver.FileName);
}