I am trying to build my first ever API and I want it to read some text from a .txt file.
I wrote the code originally to have the text be stored in memory and then remove it after the HTTP Get request. I had it working properly when I would run it in Visual Studio, so I decided to deploy it to Azure. I would then make the HTTP request to add more text into the memory and then I would essentially request it back, however I wouldn't get the text I wanted back. Instead I would get my error message saying that there is nothing in the list which holds the text I want.
I then decided to have it write the text to a .txt file then receive it from that. Once again this worked on my side, but once I published the code to Azure and send a request, I get a 500 Internal Server Error.
At the end of this long story is my question since I can't seem to find any details about .txt files on an Azure Web server.
Is it possible to have my C# class's in my Models folder of my API Web app read a .txt file on an Azure server?
Is it possible to have my C# class's in my Models folder of my API Web app read a .txt file on an Azure server?
The short answer: yes.
The slightly longer answer: yes, however...
As posted in the comments reading and writing information to and from a file in a web application can go bad really fast. Think about two users trying to write at the same time, one user reading at the moment another one is writing and so on.
Now I can imagine the only thing you want to do right now is test to see if it works, so multiple users might not be on top of mind. But even a proof of concept deserves the correct approach, since you might learn something the wrong way otherwise.
Have a look at storing your information in a data store inside Azure, there are quite a few options. For this just to work, it's probably best to use something that's not too hard to set up like Table Storage. If you run into any issues trying to get this to work, open up a new question and we'll be happy to help.
500 Internal Server Error, these is general error in server side. I reproduce same problem and its working fine by using following steps.
After deploy on Azure its show 500 error.
you find actual error to enable Application Insights and go to Failures tab. You can see actual error why occurred.
Click on Error
See Error and File location.
Check File location, if file not there location then create a file on that location. Go to advance tool
Click to go link.
Select Cmd from Debug console dropdown. and click on Site->wwwroot
Create a txt file
Output : Now its working.
I'm trying to retrieve a file from the Process.Start()-Method.
Following scenario is given:
I obtain a link from a third party program. This link can be a UNC-path, direct link to PDF/JPG/TIF-files, such as "www.certainServer.de/test.pdf", as well as link to programs on the server, which return a special file type, such as "www.certainServer.de/test.aspx".
I open the file like this
Process.Start(_path)
If the link is like "www.certainServer.de/test.aspx" the returned file is automatically downloaded to the deposited download folder.
Is there a opportunity to retrieve the downloaded file or the path to the downloaded file?
The returned Process-object from the Process.Start()-Method doesn't seem to be helpful.
Process.Start does not necessarily download a file. It simply starts a process. You just as easily could start Notepad, which has no side effects (except, of course, what you do with notepad once it's started). If the process you start (in your case, calling a web page) has external effects, the process engine knows nothing about it.
It sounds like you know where the file is supposed to be deposited, so you could use something like a FileSystemWatcher to be alerted when a new file is added (which doesn't necessarily mean it came from your process, though) or get a list of files before and after the process is run.
But there's nothing inherent to System.Process to definitively know what that process did.
Another option might be to call the URL from your code (using WebClient or something similar) and capturing the result (which might be a file, or just a web page, depending on the URL). It's not as general as starting a process and letting the default browser handle the download, but it would capture the results more definitively.
I have a quick question.
I am using the "video" tag on my web page to display video from my server say "/videos/myvideo.mp4
Video is playing fine.
The issues is when I try to delete the video from some other code (server side)
via File.Delete(physical path) I am getting "File in use" error.
Is this a known issue?
How can I delete the video physically if someone is playing that video on his page at the same time?
I have had a similar problem when trying to rename a file, using C# on Windows 7. I do have a feeling that the problem is not as severe now as it was when I wrote that code. I don't know if some Windows 7 patch has fixed it.
Some things to try:
Ensure your OS is fully patched.
Ensure the file is Close'd before attempting the delete.
Set any variables that use the file to null.
Dispose any variables that use the file.
If you are absolutely sure nothing is holding the file open, you
might need to write a loop to keep trying the Delete, say every few
seconds. (Horrible fudge, it was the only thing that worked for me.)
I have an issue with the background transfer service:
I am trying to download a file from onedrive using BackgroundDownloader, the transfer seems to be effective (some bytes are transfered), but the transfer seems to never end, and at the end the file downloaded size is 0 bytes.
In addition, the transfer never ends because if I launch a second transfer, it never starts (except if i switch the network connectivity (wifi on/off)).
I have tried the same link in the background transfer sample from MS, it gets the same behavior. However I have used the same link in IE, and the transfer goes well.
I have tried with many files (mp3), the result is the same. I have also added:
download.CostPolicy = BackgroundTransferCostPolicy.Always;
but still same result. I have also tried on wifi, debug, release.
Any idea why the file would not be saved? (I have enough space on the SD card of course)
If no answer is found, does anyone know a good implementation of this background transfer service that I could use instead of the official one?
I have read a similar post, but i just cant figure out the problem.
I have changed the windows permissions and changed routes.
When i try to save a file it throws me the exception:
Access to the path **** denied.
string route="D:\\";
FileStream fs = new FileStream(route, FileMode.Create); <--here is the problem
StreamWriter write = new StreamWriter(fs);
patient person = new patient();
patient.name = textBox1.Text;
patient.name2 = textBox2.Text;
You are trying to create a FileStream object for a directory (folder). Specify a file name (e.g. #"D:\test.txt") and the error will go away.
By the way, I would suggest that you use the StreamWriter constructor that takes an Encoding as its second parameter, because otherwise you might be in for an unpleasant surprise when trying to read the saved file later (using StreamReader).
Did you try specifing some file name?
eg:
string route="D:\\somefilename.txt";
tl;dr version: Make sure you are not trying to open a file marked in the file system as Read-Only in Read/Write mode.
I have come across this error in my travels trying to read in an XML file.
I have found that in some circumstances (detailed below) this error would be generated for a file even though the path and file name are correct.
File details:
The path and file name are valid, the file exists
Both the service account and the logged in user have Full Control permissions to the file and the full path
The file is marked as Read-Only
It is running on Windows Server 2008 R2
The path to the file was using local drive letters, not UNC path
When trying to read the file programmatically, the following behavior was observed while running the exact same code:
When running as the logged in user, the file is read with no error
When running as the service account, trying to read the file generates the Access Is Denied error with no details
In order to fix this, I had to change the method call from the default (Opening as RW) to opening the file as RO. Once I made that one change, it stopped throwing an error.
I had this issue for longer than I would like to admit.
I simply just needed to run VS as an administrator, rookie mistake on my part...
Hope this helps someone <3
If your problem persist with all those answers, try to change the file attribute to:
File.SetAttributes(yourfile, FileAttributes.Normal);
You do not have permissions to access the file.
Please be sure whether you can access the file in that drive.
string route= #"E:\Sample.text";
FileStream fs = new FileStream(route, FileMode.Create);
You have to provide the file name to create.
Please try this, now you can create.
TLDR : On my end, it had something to do with AVAST ! => Whitelist your application.
All of a sudden, I also got this UnauthorizedAccessException problem in the windows WPF program I'm writing. None of the solutions worked - except I couldn't figure out how to elevate my application to full privileges (not using VS) while at the same time, being already on the administrator account, I didn't feel the need to dig that deep in permission concerns.
The files are image files (jpg, psd, webp, etc.) I wasn't trying to open/write a directory, it has always been a valid path to a file, and I needed to write to the file, FileAccess.ReadWrite was inevitable. The files (and any of their parent directory) were not readonly (I even checked by code prior calling new FileStream(path, mode, access, share) via FileInfo.IsReadOnly) - so what happenned all of a sudden ???
Thinking about : I had an had drive crash, so I unpacked a backup of my solution code from another drive. In the meantime, I added codes in my application to PInvoke APIs to directly read hard drive sectors physical bytes as well as USB plug/unplug monitoring.
I started to get the Exception when I added those, but even though I temporarly removed the related codes from the application, I still got the UnauthorizedAccessException.
Then I remembered one thing I've done long ago, a painstaking similar issue where I wanted my application to communicate sensible data via Wifi, which was to add the executable among AVAST exceptions, and the assembly directory aswell (My app was already among the authorized apps through firewall)
Just did it for my application in AVAST settings, AND THE EXCEPTION IS GONE !!! Two whole days I'm lurking StackOverflow and the web to get moving on, FINALLY !
Details : I can't pinpoint exactly what AVAST didn't like in my application as the only changes I made :
Retrieved then launched the backup code - it worked like a charm, files (images) opens/write without problems (3 days ago)
Added USB detection (3 days ago - Just tested the code, didn't tried to open an image)
Added PInvoke physical drive direct read (2 days ago - FileStream, and the logic to define where/how to scan the damaged drive - Just tested the code, didn't tried to open an image)
Added image format detection starting from Jpg/Jfif.. 2 days ago, got the exception upon testing the code.
While searching for solutions, added an Image Gallery WPF UserControl to diplay pictures based on their signature and check which files gives the exception : almost all of them (some files opens/write okay - why ???)
Tried everything I've found on SO (since the last 2 days) until I opened AVAST settings and whitelist my application.
... now I can move on into adding a bunch of file signatures to retrieve as many datas as I could.
If this may help those who like me, aren't failing on the "I'm passing a directory path instead that of a file", yet, have no time to learn exactly why antiviruses think our own code is a malware.
Just Using the below worked for me on OSX.
var path = "TempForTest";