Error connecting to localhost during Gmail API setup in Go

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1

I’m trying to set up the Gmail API in Go but I’m running into issues. When I follow the quickstart guide and try to get the token from the web, I keep getting an error. The browser says it can’t reach the site and localhost refuses to connect.

Here’s what I’ve tried:

func getTokenFromWeb() {
    // ... other code ...
    authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline)
    fmt.Printf("Go to this URL: %v\n", authURL)
    // ... rest of the function ...
}

When I paste the generated URL into my browser, it just gives me an ERR_CONNECTION_REFUSED error.

Oddly enough, the Python version of this quickstart works fine for me. I can even use the token from the Python version in my Go code and it works. It’s just the web token retrieval in Go that’s causing problems.

Any ideas on what might be going wrong here? Is there a step I’m missing or something I need to configure differently for Go?

2

I’ve dealt with this exact problem before. The issue likely lies in how your local server is set up to handle the OAuth flow. Make sure you’ve implemented a proper HTTP server to catch the callback from Google.

Here’s a crucial step you might be missing:

http.HandleFunc("/callback", handleCallback)
go http.ListenAndServe(":8080", nil)

This sets up a server to listen on port 8080 and handle the callback. Also, double-check your Google Cloud Console. Ensure http://localhost:8080/callback is listed as an authorized redirect URI.

If it still doesn’t work, try clearing your browser cache or using an incognito window. Sometimes cached data can interfere with the OAuth process.

Lastly, verify no other applications are using port 8080 on your machine. You can change the port if needed, just remember to update it in your Google Cloud Console too.

3

yo, i had the same headache. make sure ur actually running the local server when u try to connect. add smthin like this:

http.HandleFunc(“/”, handleCallback)
go http.ListenAndServe(“:8080”, nil)

Also check ur firewall, sometimes it blocks localhost stuff. if that dont work, try a diff port maybe?

4

I encountered a similar issue when setting up the Gmail API in Go. The problem often stems from the local server not being properly initialized to handle the OAuth callback.

Here’s what worked for me:

Make sure you’ve implemented a local server to handle the callback. You need to set up a simple HTTP server that listens on a specific port (usually 8080) to catch the authorization code.

Try adding this to your code:

http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
    code := r.URL.Query().Get("code")
    // Handle the code...
})
go http.ListenAndServe(":8080", nil)

Also, double-check your Google Cloud Console settings. Ensure that http://localhost:8080 is listed as an authorized redirect URI for your OAuth 2.0 Client ID.

If you’re still having trouble, you might want to try using a different port or checking if any other applications are using port 8080. Sometimes, firewall settings can also interfere with localhost connections.

Hope this helps you resolve the issue!