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.
Related
I recently had a new project assigned to me (I'm new to C# and I'm a junior). It makes use of a Microsoft access database file (.accdb file)
I've imported the project into Visual Studio but I can't for the life of me run the code. Initially I had file register issues, and I think I managed to resolve that by getting the IT teams to install a "2007 Office System Driver: Data Connectivity Components" driver from the Microsoft website.
Bow the error says:
System.Data.OleDb.OleDbExceptions: 'Cannot open database''. It may not be a database that your application recognizes, or the file may be corrupt.'
The team I'm trying to help only has one dev (working from a different country) who is the main person to handle the code. It works on her side, but she doesn't really have the experience to help me troubleshoot this.
I tried sending her my database file, for her to swap her file for mine, and she said it was still working, so it sounds like the issue might not be to do with the file?
Could I get any help if possible? So far my only approach is to keep googling the error.
But the only resolutions I see are from people who have database files nearing their file size limit (2GB). My database file is just 1MB.
The database file is password protected (the password happens to be in the code). I opened the database file (Microsoft access opens) and entered the password and I had no issue accessing the data)
Out of luck, I managed to find the right article to help me!
The issue with Microsoft access database files is only one user can really use then at a time I believe.
I saw a forum about potential locks made by other users. I googled how to remove locks but it seems that it might not be a lock issue (Microsoft creates a lock file which I dont have).
Regardless, I assumed that the issue is still somewhat similar. Since I had access to the database in Microsoft Access, I decided to open a new database, then go to external data tab and click on access to import EVERYTHING from the other file. Then I just renamed to old file and give my new file the original name.
I reran the code and it worked!
I dont know why the other dev had no issue opening the file. My assumption is that because she is the only developer her laptop is already 'set up' in some way to run everything as normal, whereas if someone new tried (or if something happens and she has to re-open the code on a new laptop) they would have to try and replicate the 'set up' or try and work from scratch
Hope this helps
I'm trying to create software that will add a computer to an Active Directory domain. One criteria I need to meet is the machine must be added to the proper OU. In order to do this I have a set list of site locations with addresses (this is how we determine OU). This list is currently in the form of an ACCDB file, and I want to include this within the application as the Access list will not be changed.
Everything I see wants the DB file to be connected to in a different location such as server or on the local machine. My preference is to use the DB file as a reference or something inside the program's .exe file itself. I may be missing something horribly obvious, but it's been messing with me for a couple days so I'm reaching out for help.
To clarify, this software MUST be self contained (no installer). It must also be able to determine the proper OU to join to the domain (no access to shares until the PC joins the domain). It must also be user-friendly enough to avoid mistakes, meaning I want to avoid copying distributing multiple files that must go to a correct location. This is why I want to embed the ACCDB file into the application for on the fly use.
Things get much easier because this is static data. You don't have to worry about persisting this data, reclaiming changes into your program, or users accidentally deleting something, etc. You will be able to just use an embedded resource in your application. In the link, follow the examples using the image file. Text file examples will corrupt your database.
However, there is still a trick to doing this. The problem is the Access engine included with Windows will not be able to open the database as a resource, and so you will need to save this file to the local hard drive. The good news is its not as bad as it seems, because your program can do this as needed, and make sure it's right, rather than asking the user to put a file in a specific place.
As for where to put the file when you extract it... the safest and best place is the Application Data folder. You can easily get the path for this folder by checking the results of this call:
Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)
This will give you a path where standard privilege users do have write access, no matter which user.
In summary:
Embed the ACCDB as a resource.
When your program runs, get the Application Data path using the Environment object.
Open a FileStream for writing to a file based on the path from #2
Open the embedded resource as a Stream object in C#
Copy the stream from #4 to the stream from #3. Make sure to use a mechanism intended for binary data, rather than text.
Close/Dispose your streams, so no locks remain on the file. This is as simple as putting using blocks in the right places.
Open a normal Access connection to the file you just made, using any of the thousands of tutorials or examples available on the web as a guide.
In this way, you only need to distribute the final .exe file, and users won't need any special permissions to use the database. You don't have to worry if a user deletes your file; it's still embedded in the application, which will recreate it if needed every time it starts up.
The downside is a clever user may be able to manipulate the database to end up in an undesirable OU. If you need to worry about this, you should consider having the program check a web service, rather than using embedded data. Anything you embed can ultimately be altered by an end user. A web service is also nice because you can update your mapping data as your organization evolves, without needing to rebuild or redistribute the program.
I am looking for a few pointers to reaching am adequate solution to a problem/feature I need to implement/rectify in my asp.net mvc application.
My application is a LAN only interface that is run over a webserver. In this application there is a page that displays a bunch of files/folders.
I need to be able to store a set of attributes\properties about these files, and those props\attrs need to be independent of their location on the fileserver. This is my main issue, as I could easily link them to the db with the path as the primary key, but alas then as soon as the file moves their link to the db would be lost.
The types of files that need to be displayed unfortunately could be anything. .txt, .exe, media etc etc. So that provides a limiting option also from using something like the tagsharp lib.
One approach i was considering was simply storing a key somehow in the file itself, or with an ADS ( i have no experience in doing this, but am presently trying to research its potentiality).
Does anybody have any experience with this issue, and can recommend a simple approach. I am hoping i do not need to implement an ADS approach as what ive been reading so far is a little bit over my head and im not sure C# will handle the streams adequately for my needs.
Opinion based. Proposal anyway: what about an additional file which is found by a naming convention?
MyDocument.doxc
MyDomument.docx.properties
MyMovie.mp4
MyMovie.mp4.properties
When moving / renaming files, make sure you move / rename the properties file the same.
First of all thanks for taking a moment to reply.
I had considered the possibility of using a separate file. The problem is that the users of the filesystem ( which may or may not include users of the lan application ) need to be able to move/copy files independent of db application.
Therefore if a user moves a file in windows explorer, I need it to automatically move those additional properties with it. Unfortunately I cant rely on users to move those additional files on their own volition, and I cant ask users to only use the application to move files ( if i were to generate code for the program to do this ).
I need to show list of file from Remote Server. For this I already fetch the details of Remote server using Self Hosted Web Service. i.e. I fetch remote server file name and full path as JSON String and then show the information in TreeView [WPF]. Now I need to show the icons of these files. For this I think I Can use the icon within the client desktop application and I found 2 solution
http://www.codeproject.com/Articles/2532/Obtaining-and-managing-file-and-folder-icons-using#_rating
and
WPF's
System.Drawing.Icon.ExtractAssociatedIcon
However I love the solution from Later part but it doesn't work for given file name[i.e. file should present in system, which is not the case with me]. I try to run above code's sample, and Icon shown by it are not really very good or clean. So, Is there better way to extract/get Associated file Icon for extension in C#, WPF.
Thanks.
I search more and found the CodeProject's Article is only suggested way of extracting Icon. Though I am still experimenting it and in last 2 hours I am not able to show Icon in my Treeview though object seems filled correctly for me.
EDIT Solution Found: See my post below.
We are writing a library that reads in a TIF file from a scanner. Basically, its a scantron. We are examining the form and reading values from it.
Currently we have a windows test app, and we give it a filepath as a string ("c:\testing\image.tif"). It loads up the tif, reads the document correctly and parses the values.
We also have an ASP.NET web application. We have a test page that does exactly what the windows app does, we hand it an identical string, and i calls the same function on the same class from the same library. It however does NOT read the form correctly. We have verified that it does it fact load up the tif file, and it is actually filled with data (pixels we expect to be white/black are white/black when we examine the Bitmap obect in the immediate window of Visual Studio).
The specific problem is in a library called DataMatrix we use to scan a bar-code off the document. This function is supposed to return a List<string>, each of which is a barcode the library found on the document. In the windows app, this function (DataMatrixDecoder.DecodeBarcode(bitmap)) correctly returns with a Count=1. When using the asp.net app, this returns with Count=0.
Because its the exact same image file, I cannot imagine the problem is in DataMatrix. I can only assume its something with ASP.NET or something.
This isn't even my project, but another guy and I are helping our coworker figure this out, and we are just pulling our hair out. All signs indicate that ASP.NET is correctly loading and handing the image off disk to the "processor" class (which is a class library that uses the DataMatrix stuff, we are not doing ANY code in ASP.NET except for opening/handing the file to the function.).
Does anyone have any ideas as to what it might be, or different things we can check?
I'm not even sure what kind of information to give so I tried to say it all, if you have any questions please ask I'd be more than happy to elaborate on anything. Thanks.
edit:
this is the code on the ascx.cs code-behind, in a button-click event:
if (formReader.ReadTIFF(#"c:\testing\image.tif"))
{
messages.Controls.Add(HtmlHelper.DivSuccess("Read successful."));
}
The formReader class then open the file with a FileStream, and uses that to create a Bitmap. The ASP.NET application is not actually opening the file at all (we were uploading it through a FormUpload control, but after experiencing problems we dummied it down to this). This is the most perplexing thing, that it works in the windows app but not from this web site. ASP.NET has full permissions on that folder to do whatever it wants. It can open the image fine, and the bitmap it creates from the FileStream is the actual image.
edit: Also, the ReadTIFF function right now copies the FileStream into a MemoryStream, ensuring its a not a problem streaming from disk (the entire file is in memory).
How are you passing the filepath to the web application?
It is possible that the function which Decodes might be swallowing some exception.
Use reflector to examine the library (if you have not written it).
I agree. It seems your problem is most probably related to User rights on the directory where you're trying to access the files from. Try giving your Web users the Full access rights on the source directory.
EDIT
Solution Found: The problem was that the open file dialog was changing the CurrentWorkingDirectory. The reason the website never worked, was because the Environment.CurrentDirectory was set incorrectly. When I manually set the CurrentDirectory to the websites' bin folder, parsing works correctly.
Small update. Using the Windows App, and selecting the file via OpenFileDialog, will cause the barcode decoder to fail. Technically, I am using the exact same string to hand to the parser ("c:\testing\image.tif"), yet when I use the OpenFileDialog to get the string, the decoder fails. Is there a clue in this?
update: In fact, even if I don't use the string the OpenFileDialog gives me, if I just open the file dialog at all, it will fail. I don't get this. It's something simple. I need to debug the C++ DataMatrix library, really.