UploadStream 3.1.1

Optimise multi-part streaming file upload performance, offering 10x improvement in performance, and reduced memory allocation (10%-40%).

By default dotnet model form model binding loads the entire stream into memory using IFormFile - this is non-ideal for large files where processing of the stream should occur during streaming rather then buffering entire file(s) to memory/disk.

This package allows upload streams to be asynchronously processed via a delegate while maintaining generic model binding functionality with ModelState validation.

Usage

[HttpPost("upload")]
public async Task<IActionResult> Upload() {
    // returns a generic typed model, alternatively non-generic overload if no model binding is required
    MyModel model = await this.StreamFiles<MyModel>(async formFile => {
        // implement processing of stream as required via an IFormFile interface
        using (var stream = formfile.OpenReadStream())
            await ...
    });
    // ModelState is still validated from model
    if(!ModelState.IsValid)
        ...
}

Results

Results are normalised in comparison to default dotnet IFormFile model binding, the UploadStream package offers around 10x performance improvement and 10%-40% improvement in memory allocation.

Out of interest a comparison to file uploads via a base64 model was performed, interestingly this actually offers improved performance (1.5x - 2.5x) with a cost of increased memory allocations (0.3x - 0.1x) and increased memory heap trashing (gc gen1/gen2).

| Alias | File sizes | StreamFiles (us/alloc) | Base64 (us/alloc) |
|------ |-----------:|-----------------------:|------------------:|
|    Xs |    5.94 KB |          1.14x / 1.23x |     1.16x / 1.44x |
|    Sm |  106.53 KB |          3.98x / 1.43x |     2.85x / 0.30x |
|    Md |  865.37 KB |          8.66x / 1.24x |     2.36x / 0.09x |
|    Lg |    6.04 MB |          9.86x / 1.09x |     1.97x / 0.11x |
|    Xl |   21.91 MB |          9.16x / 1.08x |     1.72x / 0.14x |