To handle large downloads safely, you should stream the body directly to a file using resp.WriteTo() or a similar streaming approach.
FastHTTP is the go-to Go package for high-performance networking, often touted for being up to 10x faster than the standard net/http library. While it excels at handling thousands of small-to-medium requests per second with zero memory allocations in hot paths, downloading large files requires specific techniques to avoid overwhelming your RAM. Serving Files for Download fasthttp download file
func main() { fs := &fasthttp.FS{ Root: "./download_dir", // Your files go here GenerateIndexPages: true, AcceptByteRange: true, } fsHandler := fs.NewRequestHandler() fasthttp.ListenAndServe(":8080", func(ctx *fasthttp.RequestCtx) { fsHandler(ctx) }) } Use code with caution. Downloading Files as a Client To handle large downloads safely, you should stream
The most efficient way to serve files with FastHTTP is using the built-in FS (File System) handler. This handler is pre-optimized to handle: Serving Files for Download func main() { fs := &fasthttp
When using the fasthttp.Client to download files, the default client.Do() method reads the entire response body into memory. For massive files, this can lead to memory exhaustion.
: Allows clients to resume interrupted downloads.
func DownloadLargeFile(url string, destPath string) error { req := fasthttp.AcquireRequest() req.SetRequestURI(url) resp := fasthttp.AcquireResponse() // Perform the request if err := fasthttp.Do(req, resp); err != nil { return err } // Open destination file f, err := os.Create(destPath) if err != nil { return err } defer f.Close() // Write the response body directly to the file stream _, err = resp.BodyWriteTo(f) return err } Use code with caution. Performance & Limitations