Golang download file

You can contribute to this page on GitHub or just let us know in the comments below - Thanks for reading! Golang Code. Get url if err! Create filepath if err! Copy out , resp. The simplest way to download a file is using grab. It accepts two parameters; a destination file path and the source URL. Get uses grab. It will follow redirect responses from remote servers and use a corporate proxy if configured on the host system.

Essentially, grab. Get is a wrapper for grab. You may specify an existing or non-existing file path as the destination or you may specify an existing directory. If a directory is given as the destination, grab will determine the filename using Content-Disposition headers if they are returned by the remote server or extract a filename from the source URL. If either of these features fails, an error is returned which can be identified using grab.

If the destination filename exists, grab assumes it is a complete or partially complete download and will resume downloading from the end of the file if supported by the remote server.

Otherwise the file will be overwritten. Get and all other download functions return a grab. Response which includes context about the downloaded file; including the path where the file was saved. Get is a blocking, synchronous operation, which means that the function does not return a response until the download is complete or encounters an error. The first is wget. The main reasons I use wget is that it has a lot of useful features like recursive downloading of a website.

So you could simply do:. You can select the number of levels using -l flag. Replace the with any number, or you can use 0 to infinitely loop through and download a whole website. Also, the links on the webpages downloaded still point to the original. You can just mirror the entire website using -m , and the -r, -k and -l flags will be automated.

Is there a way to download a large file using Go that will store the content directly into a file instead of storing it all in memory before writing it to a file? Because the file is so big, storing it all in memory before writing it to a file is going to use up all the memory. The http. Response's Body is a Reader, so you can use any functions that take a Reader, to, e. In this specific case, io. Copy does the gruntwork for you.

The answer selected above using io. Copy is exactly what you need, but if you are interested in additional features like resuming broken downloads, auto-naming files, checksum validation or monitoring progress of multiple downloads, checkout the grab package. Here is a sample.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How can I efficiently download a large file using Go? Ask Question. Asked 9 years, 4 months ago. Active 3 years ago. Viewed 74k times.