FileHelpers | NET library to read/write data | CSV Processing library

I have an API method that streams uploaded files directly to disk to be scanned with a virus checker. Some of these files can be quite large, so IFormFile is a no go:

Any single buffered file exceeding 64 KB is moved from memory to a temp file on disk. Source: https://docs.microsoft.com/en-us/aspnet/core/mvc/models/file-uploads?view=aspnetcore-3.1

I have a working example that uses multipart/form-data and a really nice NuGet package that takes out the headache when working with multipart/form-data, and it works well, however I want to add a file header signature check, to make sure that the file type defined by the client is actually what they say it is. I can't rely on the file extension to do this securely, but I can use the file header signature to make it at least a bit more secure. Since I'm am streaming directly to disk, how can I extract the first bytes as it's going through the file stream?

This answer shows a nice way to use CsvHelper with generic F# option types. How do you do the same thing with FileHelpers?

I cannot figure out how to make the generic OptionConverter work. Consider the following test.csv:

I am thinking of something like a config, xml, or JSON file. But I have not found any such solution. Perhaps FileHelpers doesn't have this functionality outside of the compiled assembly, but this is a long shot in the dark. The situation is that I have several files to read from and/or to write to, that quite often change structures slightly; and also the need to add new ones to interact with when new customers are acquired. I have used the FileHelpers library succesfully before, but for the sake of not having to recompile a rather large application every time a customer changes their file structure, or a new one starts doing business with us, I need to be able to add, remove, or alter the FileHelpers structure class of a CSV, Excel, or TXT file (depending on customer needs), rather dynamically. Any guidance will be appreciated.

I have a datetime as string 2020-05-14T13:37:49.000+0000, I need convert to DateTime using C#.

Which is the valid format ? yyyy-MM-ddTHH:mm:ss.FFFZ wrong for me

I am creating an API endpoint for uploading large files. These should not be buffered in memory (at least not in their entirety), and will be streamed directly to the DB or to disk.

There are official Microsoft docs on streaming uploads to DB, but it does not show how to ensure in an unbuffered way that you don't read files larger than the limit. (The code in the sample repo has a helper that checks this by reading the entire file into memory, which defeats the purpose of streaming in the first place.)

Is there a (preferably simple) way to make the streaming fail when it reads more bytes than some specified limit? Are there perhaps other ways to ensure that users can't upload too large files?

I am attempting to write a check in my Cake build script to pull in a file from BuildParameters and check if the file contents are empty -- if contents are empty, throw an exception and quit the build.

I am attempting to use FileReadText from the FileHelpers namespace but for some reason I cannot get my build to recognize the file command. I am following the syntax and documentation found here: https://cakebuild.net/api/Cake.FileHelpers/FileHelperAliases/97F5679A

Here is the code I am trying in build.cake:

I am having trouble accessing files saved in getApplicationDocumentsDirectory on android only, I keep locale, theme and assets files stored there and when booting up the app those files are always inaccessible and as a result the app does not load, I tried using shared_prefs to track a first load scenario to use the files in assets/ and then later use the ones download but that seems to be an unreliable fix as at 2nd run they also inaccessible.

The only thing that seems to work reliable is the theme.json, but both copy functions run through the same helpers so what copies the theme over is what copies the locale over. Theme is loaded up in main.dart but the locale is loaded up with EasylocaLizationDelegate and if the files are in Document storage it can never load them up.

None of these issues are present on iOS, does anyone know of any special tricks to make this work for android, I have tried google but not really sure what to search for.

I upgraded my .net core 2.2 web api to .net core 3.1. I am now able to run it from console using dotnet myapi.dll, however when I try to host it on ISS, I get following exception.

I have installed AspNetCore Module V2 and this module is throwing exception and I am not able to understand the missing part.

Autofac.Core.DependencyResolutionException: An exception was thrown while activating ?:Microsoft.Extensions.Hosting.IHostedService[] -> Microsoft.AspNetCore.Hosting.GenericWebHostService -> Microsoft.AspNetCore.Server.IIS.Core.IISHttpServer. ---> Autofac.Core.DependencyResolutionException: An exception was thrown while invoking the constructor 'Void .ctor(Microsoft.AspNetCore.Server.IIS.Core.IISNativeApplication, Microsoft.Extensions.Hosting.IHostApplicationLifetime, Microsoft.AspNetCore.Authentication.IAuthenticationSchemeProvider, Microsoft.Extensions.Options.IOptions``1[Microsoft.AspNetCore.Builder.IISServerOptions], Microsoft.Extensions.Logging.ILogger

Following is my Program.cs