关于PHPMailer结合oauth2-google中get_oauth_token及redirectURI的技术问询

Let’s break down your questions step by step, since OAuth2 can get a bit tangled when mixing different libraries:

1. Does PHPMailer use get_oauth_token.php with theLeague’s OAuth client? #

No—the standalone get_oauth_token.php script that comes with PHPMailer is a simple, self-contained tool meant to help developers manually grab an initial refresh token. It’s a quick way to walk through the authorization code flow once to get the long-lived refresh token you need for PHPMailer.

When you use thephpleague/oauth2-google, that library handles the entire authorization flow on its own:

• It generates the authorization URL to redirect users to Google’s login
• It captures the authorization code after the user grants access
• It exchanges that code for an access token and refresh token

You don’t need to use PHPMailer’s get_oauth_token.php at all in this setup—it’s redundant because theLeague’s library already implements the same flow (but more robustly).

2. Redirect URI Logic with thephpleague/oauth2-google #

Your observations about the redirect URI are spot-on, let’s clarify the details:

• Mandatory Google Console Configuration: No matter which library you use, you must pre-configure your redirect URI in the Google Developer Console. Google will reject any authorization requests or token exchanges that use an unregistered URI.
• Automatic vs. Explicit URI Setting: TheLeague’s AbstractProvider does have logic to auto-set the redirect URI to the current request’s URL if you don’t specify it in the provider’s constructor options. However, relying on auto-setting is risky—especially if you’re working across different environments (local dev vs. production) with different domain names. It’s always better to explicitly define the redirect URI when initializing the Google Provider to avoid mismatches.
• How the URI is used:
  1. When you call getAuthorizationUrl() on the provider, it includes the redirect URI in the request to Google’s authorization endpoint.
  2. After the user grants access, Google redirects back to this exact URI with an authorization code appended.
  3. When you exchange the authorization code for tokens via getAccessToken('authorization_code', ['code' => $code]), the library automatically sends the same redirect URI to Google’s token endpoint. Google validates that this matches the one used in the initial authorization request (and that it’s registered in your console) before issuing tokens.

3. Why PHPMailer’s Examples Don’t Include get_oauth_token.php as a Redirect URI #

PHPMailer’s official examples focus on the usage of OAuth tokens within PHPMailer itself—not the full authorization flow to obtain those tokens. The examples assume you’ve already acquired a refresh token (whether via PHPMailer’s script, theLeague’s library, or another method). That’s why they don’t reference get_oauth_token.php as a redirect URI—it’s unrelated to how PHPMailer consumes the tokens.

Quick Recap #

• Use get_oauth_token.php only if you want a quick, one-off way to get a refresh token without integrating theLeague’s library.
• When using thephpleague/oauth2-google, let that library handle the full authorization flow, and make sure your redirect URI is registered in Google’s Console (preferably set explicitly in your code).
• PHPMailer only needs your refresh token (plus client ID/secret) to automatically fetch new access tokens when needed—you don’t need to pass it any redirect URI or handle the authorization flow directly.

内容的提问来源于stack exchange，提问作者decomplexity