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Exemplos de código Go

Os exemplos de código a seguir, que usam a biblioteca de cliente de APIs do Google para Go, estão disponíveis para YouTube Data API. Você pode fazer o download desses exemplos de código na pasta go do repositório de exemplos de código das APIs do YouTube no GitHub (link em inglês).

Autorizar uma solicitação

Este exemplo de código executa a autorização OAuth 2.0 verificando a presença de um arquivo local que contém credenciais de autorização. Se o arquivo não estiver presente, o script abrirá um navegador e aguardará uma resposta, e salva localmente as credenciais retornadas.

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"os/user"
	"path/filepath"
	"runtime"

	"golang.org/x/net/context"
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
)

// This variable indicates whether the script should launch a web server to
// initiate the authorization flow or just display the URL in the terminal
// window. Note the following instructions based on this setting:
// * launchWebServer = true
//   1. Use OAuth2 credentials for a web application
//   2. Define authorized redirect URIs for the credential in the Google APIs
//      Console and set the RedirectURL property on the config object to one
//      of those redirect URIs. For example:
//      config.RedirectURL = "http://localhost:8090"
//   3. In the startWebServer function below, update the URL in this line
//      to match the redirect URI you selected:
//         listener, err := net.Listen("tcp", "localhost:8090")
//      The redirect URI identifies the URI to which the user is sent after
//      completing the authorization flow. The listener then captures the
//      authorization code in the URL and passes it back to this script.
// * launchWebServer = false
//   1. Use OAuth2 credentials for an installed application. (When choosing
//      the application type for the OAuth2 client ID, select "Other".)
//   2. Set the redirect URI to "urn:ietf:wg:oauth:2.0:oob", like this:
//      config.RedirectURL = "urn:ietf:wg:oauth:2.0:oob"
//   3. When running the script, complete the auth flow. Then copy the
//      authorization code from the browser and enter it on the command line.
const launchWebServer = false

const missingClientSecretsMessage = `
Please configure OAuth 2.0
To make this sample run, you need to populate the client_secrets.json file
found at:
   %v
with information from the {{ Google Cloud Console }}
{{ https://cloud.google.com/console }}
For more information about the client_secrets.json file format, please visit:
https://developers.google.com/api-client-library/python/guide/aaa_client_secrets
`

// getClient uses a Context and Config to retrieve a Token
// then generate a Client. It returns the generated Client.
func getClient(scope string) *http.Client {
	ctx := context.Background()
	
	b, err := ioutil.ReadFile("client_secret.json")
	if err != nil {
		log.Fatalf("Unable to read client secret file: %v", err)
	}
	
	// If modifying the scope, delete your previously saved credentials
	// at ~/.credentials/youtube-go.json
	config, err := google.ConfigFromJSON(b, scope)
	if err != nil {
		log.Fatalf("Unable to parse client secret file to config: %v", err)
	}
	
	// Use a redirect URI like this for a web app. The redirect URI must be a
	// valid one for your OAuth2 credentials.
	config.RedirectURL = "http://localhost:8090"
	// Use the following redirect URI if launchWebServer=false in oauth2.go
	// config.RedirectURL = "urn:ietf:wg:oauth:2.0:oob"
	
	cacheFile, err := tokenCacheFile()
	if err != nil {
		log.Fatalf("Unable to get path to cached credential file. %v", err)
	}
	tok, err := tokenFromFile(cacheFile)
	if err != nil {
		authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
		if launchWebServer {
			fmt.Println("Trying to get token from web")
			tok, err = getTokenFromWeb(config, authURL)
		} else {
			fmt.Println("Trying to get token from prompt")
			tok, err = getTokenFromPrompt(config, authURL)
		}
		if err == nil {
			saveToken(cacheFile, tok)
		}
	}
	return config.Client(ctx, tok)
}

// startWebServer starts a web server that listens on http://localhost:8080.
// The webserver waits for an oauth code in the three-legged auth flow.
func startWebServer() (codeCh chan string, err error) {
	listener, err := net.Listen("tcp", "localhost:8090")
	if err != nil {
		return nil, err
	}
	codeCh = make(chan string)

	go http.Serve(listener, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		code := r.FormValue("code")
		codeCh <- code // send code to OAuth flow
		listener.Close()
		w.Header().Set("Content-Type", "text/plain")
		fmt.Fprintf(w, "Received code: %v\r\nYou can now safely close this browser window.", code)
	}))

	return codeCh, nil
}

// openURL opens a browser window to the specified location.
// This code originally appeared at:
//   http://stackoverflow.com/questions/10377243/how-can-i-launch-a-process-that-is-not-a-file-in-go
func openURL(url string) error {
	var err error
	switch runtime.GOOS {
	case "linux":
		err = exec.Command("xdg-open", url).Start()
	case "windows":
		err = exec.Command("rundll32", "url.dll,FileProtocolHandler", "http://localhost:4001/").Start()
	case "darwin":
		err = exec.Command("open", url).Start()
	default:
		err = fmt.Errorf("Cannot open URL %s on this platform", url)
	}
	return err
}

// Exchange the authorization code for an access token
func exchangeToken(config *oauth2.Config, code string) (*oauth2.Token, error) {
	tok, err := config.Exchange(oauth2.NoContext, code)
	if err != nil {
		log.Fatalf("Unable to retrieve token %v", err)
	}
	return tok, nil
}

// getTokenFromPrompt uses Config to request a Token and prompts the user
// to enter the token on the command line. It returns the retrieved Token.
func getTokenFromPrompt(config *oauth2.Config, authURL string) (*oauth2.Token, error) {
	var code string
	fmt.Printf("Go to the following link in your browser. After completing " +
		"the authorization flow, enter the authorization code on the command " +
		"line: \n%v\n", authURL)

	if _, err := fmt.Scan(&code); err != nil {
		log.Fatalf("Unable to read authorization code %v", err)
	}
	fmt.Println(authURL)
	return exchangeToken(config, code)
}

// getTokenFromWeb uses Config to request a Token.
// It returns the retrieved Token.
func getTokenFromWeb(config *oauth2.Config, authURL string) (*oauth2.Token, error) {
	codeCh, err := startWebServer()
	if err != nil {
		fmt.Printf("Unable to start a web server.")
		return nil, err
	}

	err = openURL(authURL)
	if err != nil {
		log.Fatalf("Unable to open authorization URL in web server: %v", err)
	} else {
		fmt.Println("Your browser has been opened to an authorization URL.",
			" This program will resume once authorization has been provided.\n")
		fmt.Println(authURL)
	}

	// Wait for the web server to get the code.
	code := <-codeCh
	return exchangeToken(config, code)
}

// tokenCacheFile generates credential file path/filename.
// It returns the generated credential path/filename.
func tokenCacheFile() (string, error) {
	usr, err := user.Current()
	if err != nil {
		return "", err
	}
	tokenCacheDir := filepath.Join(usr.HomeDir, ".credentials")
	os.MkdirAll(tokenCacheDir, 0700)
	return filepath.Join(tokenCacheDir,
		url.QueryEscape("youtube-go.json")), err
}

// tokenFromFile retrieves a Token from a given file path.
// It returns the retrieved Token and any read error encountered.
func tokenFromFile(file string) (*oauth2.Token, error) {
	f, err := os.Open(file)
	if err != nil {
		return nil, err
	}
	t := &oauth2.Token{}
	err = json.NewDecoder(f).Decode(t)
	defer f.Close()
	return t, err
}

// saveToken uses a file path to create a file and store the
// token in it.
func saveToken(file string, token *oauth2.Token) {
	fmt.Println("trying to save token")
	fmt.Printf("Saving credential file to: %s\n", file)
	f, err := os.OpenFile(file, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		log.Fatalf("Unable to cache oauth token: %v", err)
	}
	defer f.Close()
	json.NewEncoder(f).Encode(token)
}
oauth2.go

Listar playlists

Este exemplo de código chama o método playlists.list da API. Use sinalizações de linha de comando para defina os parâmetros que você quer usar na solicitação, conforme mostrado nos exemplos a seguir:

# Retrieve playlists for a specified channel
go run playlists.go oauth.go errors.go --channelId=UC_x5XG1OV2P6uZZ5FSM9Ttw

# Retrieve authenticated user's playlists
go run playlists.go oauth.go errors.go --mine=true

package main

import (
        "flag"
        "fmt"
        "log"

        "google.golang.org/api/youtube/v3"
)

var (
        method = flag.String("method", "list", "The API method to execute. (List is the only method that this sample currently supports.")

        channelId       = flag.String("channelId", "", "Retrieve playlists for this channel. Value is a YouTube channel ID.")
        hl    = flag.String("hl", "", "Retrieve localized resource metadata for the specified application language.")
        maxResults    = flag.Int64("maxResults", 5, "The maximum number of playlist resources to include in the API response.")
        mine    = flag.Bool("mine", false, "List playlists for authenticated user's channel. Default: false.")
        onBehalfOfContentOwner    = flag.String("onBehalfOfContentOwner", "", "Indicates that the request's auth credentials identify a user authorized to act on behalf of the specified content owner.")
        pageToken    = flag.String("pageToken", "", "Token that identifies a specific page in the result set that should be returned.")
        part    = flag.String("part", "snippet", "Comma-separated list of playlist resource parts that API response will include.")
        playlistId       = flag.String("playlistId", "", "Retrieve information about this playlist.")
)

func playlistsList(service *youtube.Service, part string, channelId string, hl string, maxResults int64, mine bool, onBehalfOfContentOwner string, pageToken string, playlistId string) *youtube.PlaylistListResponse {
        call := service.Playlists.List(part)
        if channelId != "" {
                call = call.ChannelId(channelId)
        }
        if hl != "" {
                call = call.Hl(hl)
        }
        call = call.MaxResults(maxResults)
        if mine != false {
                call = call.Mine(true)
        }
        if onBehalfOfContentOwner != "" {
                call = call.OnBehalfOfContentOwner(onBehalfOfContentOwner)
        }
        if pageToken != "" {
                call = call.PageToken(pageToken)
        }
        if playlistId != "" {
                call = call.Id(playlistId)
        }
        response, err := call.Do()
        handleError(err, "")
        return response
}

func main() {
        flag.Parse()

        if *channelId == "" && *mine == false && *playlistId == "" {
                log.Fatalf("You must either set a value for the channelId or playlistId flag or set the mine flag to 'true'.")
        }
        client := getClient(youtube.YoutubeReadonlyScope)

        service, err := youtube.New(client)
        if err != nil {
                log.Fatalf("Error creating YouTube client: %v", err)
        }

        response := playlistsList(service, "snippet,contentDetails", *channelId, *hl, *maxResults, *mine, *onBehalfOfContentOwner, *pageToken, *playlistId)

        for _, playlist := range response.Items {
                playlistId := playlist.Id
                playlistTitle := playlist.Snippet.Title

                // Print the playlist ID and title for the playlist resource.
                fmt.Println(playlistId, ": ", playlistTitle)
        }
}
playlists.go

Recuperar meus envios

Este exemplo de código chama o método playlistItems.list da API para recuperar uma lista de vídeos enviados ao canal associado à solicitação. O código também chama a função channels.list com o parâmetro mine definido como true para recuperar o ID da playlist que identifica os vídeos enviados do canal.

package main

import (
	"fmt"
	"log"

	"google.golang.org/api/youtube/v3"
)

// Retrieve playlistItems in the specified playlist
func playlistItemsList(service *youtube.Service, part string, playlistId string, pageToken string) *youtube.PlaylistItemListResponse {
	call := service.PlaylistItems.List(part)
	call = call.PlaylistId(playlistId)
	if pageToken != "" {
		call = call.PageToken(pageToken)
	}
	response, err := call.Do()
	handleError(err, "")
	return response
}

// Retrieve resource for the authenticated user's channel
func channelsListMine(service *youtube.Service, part string) *youtube.ChannelListResponse {
	call := service.Channels.List(part)
	call = call.Mine(true)
	response, err := call.Do()
	handleError(err, "")
	return response
}

func main() {
	client := getClient(youtube.YoutubeReadonlyScope)
	service, err := youtube.New(client)
	
	if err != nil {
		log.Fatalf("Error creating YouTube client: %v", err)
	}

	response := channelsListMine(service, "contentDetails")

	for _, channel := range response.Items {
		playlistId := channel.ContentDetails.RelatedPlaylists.Uploads
		
		// Print the playlist ID for the list of uploaded videos.
		fmt.Printf("Videos in list %s\r\n", playlistId)

		nextPageToken := ""
		for {
			// Retrieve next set of items in the playlist.
			playlistResponse := playlistItemsList(service, "snippet", playlistId, nextPageToken)
			
			for _, playlistItem := range playlistResponse.Items {
				title := playlistItem.Snippet.Title
				videoId := playlistItem.Snippet.ResourceId.VideoId
				fmt.Printf("%v, (%v)\r\n", title, videoId)
			}

			// Set the token to retrieve the next page of results
			// or exit the loop if all results have been retrieved.
			nextPageToken = playlistResponse.NextPageToken
			if nextPageToken == "" {
				break
			}
			fmt.Println()
		}
	}
}
my_uploads.go

Pesquisar por palavra-chave

Este exemplo de código chama o método search.list da API para recuperar os resultados da pesquisa associados a uma palavra-chave específica.

package main

import (
	"flag"
	"fmt"
	"log"
	"net/http"

	"google.golang.org/api/googleapi/transport"
	"google.golang.org/api/youtube/v3"
)

var (
	query      = flag.String("query", "Google", "Search term")
	maxResults = flag.Int64("max-results", 25, "Max YouTube results")
)

const developerKey = "YOUR DEVELOPER KEY"

func main() {
	flag.Parse()

	client := &http.Client{
		Transport: &transport.APIKey{Key: developerKey},
	}

	service, err := youtube.New(client)
	if err != nil {
		log.Fatalf("Error creating new YouTube client: %v", err)
	}

	// Make the API call to YouTube.
	call := service.Search.List("id,snippet").
		Q(*query).
		MaxResults(*maxResults)
	response, err := call.Do()
	handleError(err, "")

	// Group video, channel, and playlist results in separate lists.
	videos := make(map[string]string)
	channels := make(map[string]string)
	playlists := make(map[string]string)

	// Iterate through each item and add it to the correct list.
	for _, item := range response.Items {
		switch item.Id.Kind {
		case "youtube#video":
			videos[item.Id.VideoId] = item.Snippet.Title
		case "youtube#channel":
			channels[item.Id.ChannelId] = item.Snippet.Title
		case "youtube#playlist":
			playlists[item.Id.PlaylistId] = item.Snippet.Title
		}
	}

	printIDs("Videos", videos)
	printIDs("Channels", channels)
	printIDs("Playlists", playlists)
}

// Print the ID and title of each result in a list as well as a name that
// identifies the list. For example, print the word section name "Videos"
// above a list of video search results, followed by the video ID and title
// of each matching video.
func printIDs(sectionName string, matches map[string]string) {
	fmt.Printf("%v:\n", sectionName)
	for id, title := range matches {
		fmt.Printf("[%v] %v\n", id, title)
	}
	fmt.Printf("\n\n")
}
search_by_keyword.go

Enviar um vídeo

Este exemplo de código chama o método videos.insert da API para fazer upload de um vídeo para o canal associadas à solicitação.

package main

import (
	"flag"
	"fmt"
	"log"
	"os"
	"strings"

	"google.golang.org/api/youtube/v3"
)

var (
	filename    = flag.String("filename", "", "Name of video file to upload")
	title       = flag.String("title", "Test Title", "Video title")
	description = flag.String("description", "Test Description", "Video description")
	category    = flag.String("category", "22", "Video category")
	keywords    = flag.String("keywords", "", "Comma separated list of video keywords")
	privacy     = flag.String("privacy", "unlisted", "Video privacy status")
)

func main() {
	flag.Parse()

	if *filename == "" {
		log.Fatalf("You must provide a filename of a video file to upload")
	}

	client := getClient(youtube.YoutubeUploadScope)

	service, err := youtube.New(client)
	if err != nil {
		log.Fatalf("Error creating YouTube client: %v", err)
	}

	upload := &youtube.Video{
		Snippet: &youtube.VideoSnippet{
			Title:       *title,
			Description: *description,
			CategoryId:  *category,
		},
		Status: &youtube.VideoStatus{PrivacyStatus: *privacy},
	}

	// The API returns a 400 Bad Request response if tags is an empty string.
	if strings.Trim(*keywords, "") != "" {
		upload.Snippet.Tags = strings.Split(*keywords, ",")
	}

	call := service.Videos.Insert("snippet,status", upload)

	file, err := os.Open(*filename)
	defer file.Close()
	if err != nil {
		log.Fatalf("Error opening %v: %v", *filename, err)
	}

	response, err := call.Media(file).Do()
	handleError(err, "")
	fmt.Printf("Upload successful! Video ID: %v\n", response.Id)
}
upload_video.go