Querystring Parameters in Go's GET Requests

In Go, sending GET requests with querystring parameters can be achieved using http.Client. However, this task may not be as straightforward as it appears.

To overcome this challenge, you can leverage the net/url package. Its Values type provides a convenient mechanism for building querystrings. Consider the following example:

import (
    "fmt"
    "log"
    "net/http"
    "os"
    "net/url"
)

func main() {
    // Create a new request object with an initial URL.
    req, err := http.NewRequest("GET", "http://api.themoviedb.org/3/tv/popular", nil)
    if err != nil {
        log.Print(err)
        os.Exit(1)
    }

    // Get the existing query parameters from the request URL.
    q := req.URL.Query()

    // Add your querystring parameters to the `q` map.
    q.Add("api_key", "key_from_environment_or_flag")
    q.Add("another_thing", "foo & bar")

    // Encode the updated `q` map into a raw querystring and set it in the request.
    req.URL.RawQuery = q.Encode()

    // Retrieve the final URL with the querystring for debugging purposes.
    fmt.Println(req.URL.String())
    // Output:
    // http://api.themoviedb.org/3/tv/popular?another_thing=foo & bar&api_key=key_from_environment_or_flag
}

This code demonstrates how to dynamically build querystring parameters without resorting to string concatenation. The Encode method of url.Values ensures that special characters are properly encoded for transmission.