what is r url query golang code example

Example: golang http get query parameters

package main

import (
    "log"
    "net/http"
)

func main() {
    http.HandleFunc("/", handler)
    http.ListenAndServe(":8080", nil)
}

func handler(w http.ResponseWriter, r *http.Request) {

    keys, ok := r.URL.Query()["key"]
    
    if !ok || len(keys[0]) < 1 {
        log.Println("Url Param 'key' is missing")
        return
    }

    // Query()["key"] will return an array of items, 
    // we only want the single item.
    key := keys[0]

    log.Println("Url Param 'key' is: " + string(key))
}