Get a URL Parameter from a Request

· 175 words · 1 minute read
#get #http #key #parameter #query #request #router #single #slide #string #url

Often it’s important to read off the parameters sent through from the request. If it’s a GET request these will lie within the url itself and can be read using the request’s URL property. It’s important to note that when getting the parameters in this way it will always return an array (or slice?).

Our example below will act a little like an echo server, we listen for any requests and log the result of key if it’s present.

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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))
}

Example when calling localhost:8080/?key=hello%20golangcode.com:

Showing Print of Url Param

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Author:  Edd Turtle

Edd is the Lead Developer at Hoowla, a prop-tech startup, where he spends much of his time working on production-ready Go and PHP code. He loves coding, but also enjoys cycling and camping in his spare time.

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