Why is `x-goog-api-key` used instead of the `Authorization` header?

[kernusr]

client/src/Factory.php

Lines 120 to 122 in 6dca9a5

	if ($this->apiKey !== null) {
	$this->headers['x-goog-api-key'] = trim($this->apiKey);
	}

Why not replace this code with the one below

if ($this->apiKey !== null) {
        $this->headers['Authorization'] = 'Bearer ' . trim($this->apiKey);
}

This approach is described in the documentation from Google https://ai.google.dev/gemini-api/docs/oauth#curl

For example, I use a proxy to access gemini api and it requires authorization only using the Authorization header. And most likely I'm not alone in this problem.

[Plytas]

@kernusr I don't think this is the same. I've tried it out locally and I get

Gemini\Exceptions\TransporterException  Client error: `POST https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash-exp:streamGenerateContent` resulted in a `401 Unauthorized` response.

The page you linked uses OAuth access tokens and not API key.

[Plytas]

However, this approach works if you acquire needed scopes and use access token. It might be a good addition to the package to provide alternative authentication methods. This would open up a possibility to let your clients authenticate via OAuth and perform LLM generation on their behalf.

What do you think @aydinfatih?

@kernusr would you be willing to open up a PR?

[kernusr]

However, this approach works if you acquire needed scopes and use access token. It might be a good addition to the package to provide alternative authentication methods. This would open up a possibility to let your clients authenticate via OAuth and perform LLM generation on their behalf.

What do you think @aydinfatih?

@kernusr would you be willing to open up a PR?

I have a few options that I could suggest:

1. Just install the 2nd header, along with `x-goog-api-key``

if ($this->apiKey !== null) {
        $this->headers['x-goog-api-key'] = trim($this->apiKey); 
        $this->headers['Authorization'] = 'Bearer ' . trim($this->apiKey);
}

But I'm not sure what kind of detrimental impact this might have in different scenarios.

2. Add the $oauthKey property and the withOauthKey() method to the \Gemini\Factory class
   This way, the static call of the instance with Gemini::client() will become inapplicable for users with Oauth Authentification.
   It will be possible to obtain a client instance only through the Factory:

$client = Gemini::factory()
    ->withOauthKey('sk-****')
    ->make();

[kernusr]

I am more inclined to the second option, as it guarantees more transparent behavior.
If you help me with the choice, I will gladly contribute

[Plytas]

I'm not a maintainer of this package, so I can only give my opinion. I also think that 2nd option would be better, with method name being withAccessToken().

[kernusr]

withAccessToken

Oh yeah! That's more accurate! Thanks for the tip.

[Plytas]

Closing due to inactivity. @kernusr feel free to re-open if this is something you still need.