Go Examples

Fetch and filter data

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"sort"
)

type Response struct {
	Metadata struct {
		Dataset     string `json:"dataset"`
		RecordCount int    `json:"recordCount"`
	} `json:"metadata"`
	Data []WindowsUpdate `json:"data"`
}

type WindowsUpdate struct {
	OSType         string `json:"OSType"`
	MajorVersion   int    `json:"MajorVersion"`
	WindowsVersion string `json:"WindowsVersion"`
	KBNumber       string `json:"KBNumber"`
	OSBuild        string `json:"OSBuild"`
	FullVersion    string `json:"FullVersion"`
	ReleaseDate    string `json:"ReleaseDate"`
	ReleaseType    string `json:"ReleaseType"`
	IsExpired      bool   `json:"IsExpired"`
	ArticleUrl     string `json:"ArticleUrl"`
}

func main() {
	resp, err := http.Get("https://api.datafornerds.io/v2/microsoft/windows-11-update-history.json")
	if err != nil {
		panic(err)
	}
	defer resp.Body.Close()

	var result Response
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		panic(err)
	}

	fmt.Printf("%s: %d records\n", result.Metadata.Dataset, result.Metadata.RecordCount)

	// Filter to standard releases
	var standard []WindowsUpdate
	for _, u := range result.Data {
		if u.ReleaseType == "Standard" {
			standard = append(standard, u)
		}
	}

	// Sort by date descending and print latest 5
	sort.Slice(standard, func(i, j int) bool {
		return standard[i].ReleaseDate > standard[j].ReleaseDate
	})
	for _, u := range standard[:5] {
		fmt.Printf("  %s  %s  %s\n", u.ReleaseDate, u.KBNumber, u.OSBuild)
	}
}

Conditional requests with ETag

package main

import (
	"fmt"
	"io"
	"net/http"
)

func getIfChanged(url string, etag *string) ([]byte, bool, error) {
	req, _ := http.NewRequest("GET", url, nil)
	if *etag != "" {
		req.Header.Set("If-None-Match", *etag)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, false, err
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusNotModified {
		return nil, false, nil
	}

	*etag = resp.Header.Get("ETag")
	body, err := io.ReadAll(resp.Body)
	return body, true, err
}

func main() {
	url := "https://api.datafornerds.io/v2/microsoft/language-codes.json"
	etag := ""

	data, changed, _ := getIfChanged(url, &etag)
	fmt.Printf("Changed: %v, Size: %d, ETag: %s\n", changed, len(data), etag)

	// Second call - should return 304
	_, changed, _ = getIfChanged(url, &etag)
	fmt.Printf("Changed: %v\n", changed) // false
}

Language code lookup

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
)

func main() {
	resp, _ := http.Get("https://api.datafornerds.io/v2/microsoft/language-codes.json")
	defer resp.Body.Close()

	var result struct {
		Data []struct {
			LanguageCode string `json:"LanguageCode"`
			Description  string `json:"Description"`
			BCP47        string `json:"BCP47"`
		} `json:"data"`
	}
	json.NewDecoder(resp.Body).Decode(&result)

	lookup := make(map[string]string)
	for _, r := range result.Data {
		lookup[r.LanguageCode] = r.BCP47
	}

	fmt.Println(lookup["1033"]) // en-US
}