## Can Goroutines Speed Up File Downloads in Golang?

Parallelize File Downloads in Golang Using Goroutines

Question:

Can we leverage goroutines to download multiple files concurrently?

Code Context:

<code class="go">package main

import (
    "fmt"
    "io"
    "io/ioutil"
    "net/http"
    "net/url"
    "os"
    "path/filepath"
    "sync"
)

// ... (existing Dropbox access token handling code)

var wg sync.WaitGroup

func downloadFile(file File, token TokenResponse) {
    // Acquire WaitGroup counter
    wg.Add(1)
    defer wg.Done() // Release counter when function returns

    downloadURL := fmt.Sprintf("https://api-content.dropbox.com/1/files/dropbox/%s?access_token=%s", file.Path, token.AccessToken)
    resp, err := http.Get(downloadURL)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    filename := filepath.Base(file.Path)
    outFile, err := os.Create(filename)
    if err != nil {
        panic(err)
    }
    defer outFile.Close()

    io.Copy(outFile, resp.Body)
}

func main() {
    // ... (existing Dropbox authorization and file list code)

    // Spawn goroutines for file downloads
    for _, file := range flr.FileList {
        go downloadFile(file, tr)

        if count >= 2 {
            break
        }
    }

    // Wait for all goroutines to complete before exiting
    wg.Wait()
}</code>

This modified code uses a sync.WaitGroup to ensure that the main goroutine doesn't exit until all file downloads are complete. This allows goroutines to download files in parallel, improving performance.

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