Complete the steps described in the rest of this page to create a simple Go
command-line application that makes requests to the Google Apps Script API.
Prerequisites
To run this quickstart, you need the following prerequisites:
package main
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"google.golang.org/api/option"
"google.golang.org/api/script/v1"
)
// Retrieve a token, saves the token, then returns the generated client.
func getClient(config *oauth2.Config) *http.Client {
// The file token.json stores the user's access and refresh tokens, and is
// created automatically when the authorization flow completes for the first
// time.
tokFile := "token.json"
tok, err := tokenFromFile(tokFile)
if err != nil {
tok = getTokenFromWeb(config)
saveToken(tokFile, tok)
}
return config.Client(context.Background(), tok)
}
// Request a token from the web, then returns the retrieved token.
func getTokenFromWeb(config *oauth2.Config) *oauth2.Token {
authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
fmt.Printf("Go to the following link in your browser then type the "+
"authorization code: \n%v\n", authURL)
var authCode string
if _, err := fmt.Scan(&authCode); err != nil {
log.Fatalf("Unable to read authorization code: %v", err)
}
tok, err := config.Exchange(context.TODO(), authCode)
if err != nil {
log.Fatalf("Unable to retrieve token from web: %v", err)
}
return tok
}
// Retrieves a token from a local file.
func tokenFromFile(file string) (*oauth2.Token, error) {
f, err := os.Open(file)
if err != nil {
return nil, err
}
defer f.Close()
tok := &oauth2.Token{}
err = json.NewDecoder(f).Decode(tok)
return tok, err
}
// Saves a token to a file path.
func saveToken(path string, token *oauth2.Token) {
fmt.Printf("Saving credential file to: %s\n", path)
f, err := os.OpenFile(path, 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)
}
func main() {
ctx := context.Background()
b, err := ioutil.ReadFile("credentials.json")
if err != nil {
log.Fatalf("Unable to read client secret file: %v", err)
}
// If modifying these scopes, delete your previously saved token.json.
config, err := google.ConfigFromJSON(b, "https://www.googleapis.com/auth/script.projects")
if err != nil {
log.Fatalf("Unable to parse client secret file to config: %v", err)
}
client := getClient(config)
srv, err := script.NewService(ctx, option.WithHTTPClient(client))
if err != nil {
log.Fatalf("Unable to retrieve Script client: %v", err)
}
req := script.CreateProjectRequest{Title: "My Script"}
createRes, err := srv.Projects.Create(&req).Do()
if err != nil {
// The API encountered a problem.
log.Fatalf("The API returned an error: %v", err)
}
content := &script.Content{
ScriptId: createRes.ScriptId,
Files: []*script.File{{
Name: "hello",
Type: "SERVER_JS",
Source: "function helloWorld() {\n console.log('Hello, world!');}",
}, {
Name: "appsscript",
Type: "JSON",
Source: "{\"timeZone\":\"America/New_York\",\"exceptionLogging\":" +
"\"CLOUD\"}",
}},
}
updateContentRes, err := srv.Projects.UpdateContent(createRes.ScriptId,
content).Do()
if err != nil {
// The API encountered a problem.
log.Fatalf("The API returned an error: %v", err)
}
log.Printf("https://script.google.com/d/%v/edit", updateContentRes.ScriptId)
}
Step 3: Run the sample
Build and run the sample using the following command from your working
directory:
go run quickstart.go
The first time you run the sample, it prompts you to authorize access:
Browse to the provided URL in your web browser.
If you're not already signed in to your Google account, you're
prompted to sign in. If you're signed in to multiple Google accounts, you
are asked to select one account to use for authorization.
Click the Accept button.
Copy the code you're given, paste it into the command-line prompt, and press
Enter.
Notes
Authorization information is stored on the file system, so subsequent
executions don't prompt for authorization.
The authorization flow in this example is designed for a command-line
application. For information on how to perform authorization in a web
application, see
Using OAuth 2.0 for Web Server Applications .
Troubleshooting
This section describes some common issues that you may encounter while
attempting to run this quickstart and suggests possible solutions.
This app isn't verified
If the OAuth consent screen displays the warning "This app isn't verified," your
app is requesting scopes that provide access to sensitive user data. If your
application uses sensitive scopes, your app must go through the
verification process
to remove that warning and other limitations. During the development phase, you
can continue past this warning by selecting Advanced > Go to {Project Name}
(unsafe).
File not found error for credentials.json
When running the sample, you might receive a file not found or no such file error regarding credentials.json.
This error occurs when you have not authorized the desktop application credentials
as detailed in the Prerequisites section above. To learn how to create credentials
for a desktop application, go to Create credentials.
Once you create the credentials, make sure the downloaded JSON file is saved as
credentials.json. Then move the file to your working directory with the rest of the
sample quickstart code.
