This program helps you download files in multiple chunks to help parallelize the download. This only works if the server supports partial requests from the client for file downloads. Typically, servers advertise this using the Accept-Ranges HTTP response header. Clients can use the Range HTTP request header to indicate what part of the object it wishes to fetch. The code checks for such support, and then follows up with requests for multiple different chunks in parallel and rearranges them locally to reconstitute the file.

Build the program using go build main.go

By default, the program downloads the recent golang binary release for linux (https://go.dev/dl/go1.20.3.linux-amd64.tar.gz). But it can take a URL (--url) as an input and also an optional --output to specify the file path. The user can also customize the number of chunks to download in parallel using the -parallel flag, the default is 10.

Running the program:

• Provide your own URL:

  ./main --url="https://go.dev/dl/go1.20.3.windows-amd64.zip"

• Provide your own URL and desired output file path:

  ./main --url="https://go.dev/dl/go1.20.3.windows-amd64.zip" --output=downloads/windows-amd64-archive.zip

• Provide your own URL, desired output file path, and desired number of chunks:

  ./main --url="https://go.dev/dl/go1.20.3.windows-amd64.zip" --output=downloads/windows-amd64-archive.zip --parallel=20