image upload on url path in asp .net core web api

To improve the code with test cases, you can use a testing framework like NUnit or xUnit to write unit tests for the UploadImage method. 

// Add the necessary using statements
using Xunit;

public class ImagesControllerTests
{
    [Fact]
    public async Task UploadImage_ValidImage_ReturnsOkResult()
    {
        // Arrange
        var controller = new ImagesController();
        var model = new ImageUploadModel
        {
            Name = "TestImage",
            File = new FormFile(Stream.Null, 0, 0, "test.jpg", "test.jpg")
        };

        // Act
        var result = await controller.UploadImage(model);

        // Assert
        Assert.IsType(result);
    }

    [Fact]
    public async Task UploadImage_NoFile_ReturnsBadRequest()
    {
        // Arrange
        var controller = new ImagesController();
        var model = new ImageUploadModel
        {
            Name = "TestImage",
            File = null
        };

        // Act
        var result = await controller.UploadImage(model);

        // Assert
        Assert.IsType(result);
    }

    // Add more test cases for different scenarios such as file size exceeding the limit,
    // invalid file type, etc.
}

The first test case, UploadImage_ValidImage_ReturnsOkResult, checks if the UploadImage method returns an OkObjectResult when a valid image is uploaded. The second test case, UploadImage_NoFile_ReturnsBadRequest, verifies that the method returns a BadRequestObjectResult when no file is uploaded. You can add more test cases to cover different scenarios, such as when the file size exceeds the limit or when an invalid file type is uploaded. Use assertions to verify the expected behavior of the UploadImage method.

Try this
 

[Route("SaveFile")]
        [HttpPost]
        public JsonResult SaveFile()
        {
            try
            {
                var httpRequest = Request.Form;
                var postedFile = httpRequest.Files[0];
                string filename = postedFile.FileName;
                var physicalPath = _env.ContentRootPath + "/Photos/" + filename;

                using (var stream = new FileStream(physicalPath, FileMode.Create))
                {
                    stream.CopyTo(stream);
                }

                return new JsonResult(filename);
            }
            catch (Exception)
            {
                return new JsonResult("anonymous.png");
            }
        }

 

Reference My article: https://www.c-sharpcorner.com/article/net-core-3-1-web-api-crud/

Define a model for the image upload request, which includes a property to hold the image data.

public class ImageUploadRequest
{
    public IFormFile Image { get; set; }
}

create an action method that accepts the image upload request and handles the file upload. Use the HttpPost attribute to indicate that the action method accepts HTTP POST requests

[HttpPost("upload")]
public IActionResult UploadImage([FromForm] ImageUploadRequest request)
{
    if (request.Image == null || request.Image.Length <= 0)
    {
        return BadRequest("No image file provided.");
    }

    // Validate the file if needed

    // Generate a unique file name or use the original file name
    string fileName = Guid.NewGuid().ToString() + Path.GetExtension(request.Image.FileName);

    // Construct the file path where you want to save the image
    string filePath = Path.Combine("wwwroot/images", fileName);

    // Save the image file to the specified path
    using (var fileStream = new FileStream(filePath, FileMode.Create))
    {
        request.Image.CopyTo(fileStream);
    }

    // Optionally, you can return the URL path of the saved image
    string imageUrl = "https://example.com/images/" + fileName;
    return Ok(imageUrl);
}

the image is saved to the wwwroot/images folder using a unique file name generated by Guid.NewGuid(). You can modify the file path and naming strategy as per your requirement.

Configure the static files middleware to serve the uploaded images. In the Configure method of your Startup class

app.UseStaticFiles();

adjust the file path and URL path based on your application's requirements. Also, ensure that the appropriate file system permissions are set to allow writing and reading the image files.

Now, when you send a POST request to the /upload endpoint with the image file in the request body, it will be saved to the specified URL path, and the URL path will be returned in the response.

public class ImageUploadModel
{
    public string Name { get; set; }
    public IFormFile File { get; set; }
}

[ApiController]
[Route("api/images")]
public class ImagesController : ControllerBase
{
    [HttpPost]
    public async Task UploadImage([FromForm] ImageUploadModel model)
    {
        if (model.File == null || model.File.Length <= 0)
        {
            return BadRequest("No file uploaded.");
        }

        // Validate and process the uploaded image here
        // Validate file size
        var fileSizeLimit = 5 * 1024 * 1024; // 5MB
        if (model.File.Length > fileSizeLimit)
        {
            return BadRequest("File size exceeds the limit.");
        }

        // Validate file type
        var allowedExtensions = new[] { ".jpg", ".jpeg", ".png" };
        var fileExtension = Path.GetExtension(model.File.FileName).ToLowerInvariant();
        if (!allowedExtensions.Contains(fileExtension))
        {
            return BadRequest("Invalid file type. Only JPG, JPEG, and PNG files are allowed.");
        }

        // Process the image
        using (var image = Image.Load(model.File.OpenReadStream()))
        {
            // Resize the image if necessary
            var maxWidth = 800;
            if (image.Width > maxWidth)
            {
                image.Mutate(x => x.Resize(maxWidth, 0));
            }

            // Save the processed image to a file on the server
            var fileName = $"{Guid.NewGuid()}{fileExtension}";
            string filePath = Path.Combine("path/to/save/images", fileName);
            image.Save(filePath);
        }

        // Return a response indicating the successful upload
        return Ok("Image uploaded and processed successfully.");
    }
}

For more details check the below links.
https://www.c-sharpcorner.com/blogs/upload-image-in-asp-net-core-web-api-60-with-postman
https://stackoverflow.com/questions/73498624/how-do-i-upload-an-image-in-asp-net-core-web-api-with-other-form-data
https://www.codingsonata.com/file-upload-with-data-using-asp-net-core-web-api/