Methods to add recordsdata utilizing minimal APIs in ASP.NET Core

1. Launch the Visible Studio 2022 IDE.
2. Click on on “Create new mission.”
3. Within the “Create new mission” window, choose “ASP.NET Core Internet API” from the listing of templates displayed.
4. Click on Subsequent.
5. Within the “Configure your new mission” window, specify the title and placement for the brand new mission. Optionally test the “Place resolution and mission in the identical listing” test field, relying in your preferences.
6. Click on Subsequent.
7. Within the “Extra Data” window proven subsequent, choose “.NET 9.0 (Commonplace Time period Assist)” because the framework model and uncheck the test field that claims “Use controllers,” as we’ll be utilizing minimal APIs on this mission.
8. Elsewhere within the “Extra Data” window, go away the “Authentication Kind” set to “None” (the default) and ensure the test packing containers “Allow Open API Assist,” “Configure for HTTPS,” and “Allow Docker” stay unchecked. We gained’t be utilizing any of these options right here.
9. Click on Create.

We’ll use this ASP.NET Core Internet API mission to work with the code examples given within the sections beneath.

IFormFile and IFormFileCollection in ASP.NET Core

Within the current variations of ASP.NET Core, minimal APIs present help for importing recordsdata utilizing the IFormFile and IFormFileCollection interfaces. Whereas IFormFile is used to add a single file, IFormFileCollection is used to add a number of recordsdata. The next code snippet illustrates how one can add a single file utilizing IFormFile in your minimal API software.

app.MapPost("/add", async (IFormFile file) =>
{
    var tempFile = Path.GetTempFileName();
    utilizing var fileStream = File.OpenWrite(tempFile);
    await file.CopyToAsync(fileStream);
});

Notice that the File.OpenWrite methodology accepts the trail to a file in your file system as a parameter and returns a FileStream occasion. As its title signifies, a FileStream object gives a Stream for a file, that means a sequence of bytes.

Equally, the next piece of code reveals how one can add a number of recordsdata utilizing the IFormFileCollection interface.

app.MapPost("/upload_multiple_files", async (IFormFileCollection recordsdata) =>
{
    foreach (var file in recordsdata)
    {
        var tempFile = Path.GetTempFileName();
        utilizing var fileStream = File.OpenWrite(tempFile);
        await file.CopyToAsync(fileStream);
    }
});

Usually we’ll need to do extra with a file than merely add it. If we need to parse or manipulate the contents of a file [OK?], we will make the most of the StreamReader class. StreamReader is a high-level class, constructed on prime of FileStream, that enables us to learn the characters from a byte stream. StreamReader may also deal with character encoding (UTF-8, ASCII, and many others.) if wanted.

Let’s say you may have a file that incorporates writer data that you simply need to insert right into a database desk. Assuming every line of textual content within the file represents a special writer file, you can embrace the next code in your Program.cs file to add the contents of the file, line by line, to a minimal API endpoint.

app.MapPost("/writer/add", (IFormFile file,
    [FromServices] IAuthorRepository authorRepository) =>
{
    utilizing var streamReader = new StreamReader(file.OpenReadStream());
    whereas (streamReader.Peek() >= 0)
        authorRepository.Create(streamReader.ReadLine() ?? string.Empty);
});

You may use the previous code snippet to learn a group of writer information represented as JSON, for instance, after which insert these data in a database desk. Notice that I’ve omitted the supply code of the IAuthorRepository interface and its carried out lessons right here for brevity.

Avoiding anti-forgery errors when importing recordsdata

When importing recordsdata in ASP.NET Core, you might typically encounter anti-forgery errors. ASP.NET Core points these errors to warn of cross-site request forgery assaults.

In case your endpoint is protected and it doesn’t require anti-forgery safety, you’ll be able to disable anti-forgery validation for the endpoint by utilizing the DisableAntiforgery methodology, as proven within the following code.