TypeError: Cannot read properties of undefined (reading 'access_token')

[imunderwater]

When working with GitHub OAuth2, everything seems to work fine initially. However, when the auth server redirects to the client callback, an error is thrown indicating: TypeError: Cannot read properties of undefined (reading 'access_token'). I tested it with other libraries, such as simple-oauth2, and it works fine. This issue appears to be related to oauth2-client and seems to be a bug that needs to be fixed.

[imunderwater]

OAuth2Token should be of type unknown, we don't know what is the response format that the provider return.

@evert can you check this issue please

[evert]

Please share your code so I can reproduce this issue! Redact any secrets. I want to see your config + it would also be helpful to see an example of the url you're parsing (also redact any tokens)

[imunderwater]

  const client = new OAuth2Client({
    authorizationEndpoint,
    tokenEndpoint,
    clientSecret,
    clientId,
  });
  async function createAuthorizationUri(
    state: string,
    redirect_uri,
  ): Promise<string> {
    const authorizationUri = await client.authorizationCode.getAuthorizeUri({
      redirectUri: redirect_uri,
      state: state,
      scope: ["read:user"],
    });

    return authorizationUri;
  }

  async function validateAuthorizationCode(code: string, redirect_uri): Promise<object> {
      const token = await client.authorizationCode.getToken({ code, redirect_uri });
     return token;
}

its the same code that i got google auth working, but instead for github doesn't work (it throws an error)

[evert]

Could you share the configuration values you're using?

[imunderwater]

sorry for the late reply
@evert here it is.

const client = new OAuth2Client({
    authorizationEndpoint: "https://github.com/login/oauth/authorize",
    tokenEndpoint: "https://github.com/login/oauth/access_token",
    clientSecret,
    clientId,
  });

as the Github oauth documentation.

[evert]

I started testing this, and at the very least this line is wrong (Typescript should error on this):

  const token = await client.authorizationCode.getToken({ code, redirect_uri });

Note that redirect_uri should be redirectUri. After that fix I was able to replicate the issue.

So it looks like Github actually 2 bugs, not this library. The issue is that Github replies with a application/x-www-form-urlencoded, when it should reply with application/json. This is non-standard behavior. Luckily it seems that adding an Accept header fixes this and doesn't have any real drawbacks.

A second issue is that Github responds with 200 OK for error =(. Pretty bad! But I can add a workaround for this too.

[evert]

I also submitted a bug report here: https://github.com/orgs/community/discussions/135818

Lastly, i think the feedback in this library could be a bit better: TypeError: Cannot read properties of undefined (reading 'access_token) is not a great error for this kind of thing!

[imunderwater]

I understand. Given that it works fine with other libraries, do you think the issue lies on oauth2-client or GitHub (or both?) Should I try adding an Accept header to the request?

[evert]

It's 100% a Github issue, but adding the Accept header will fix the issue for you (although errors will not yet be correctly processed). I do intend to add these workarounds to this library as well so in the future it's not an issue.

[imunderwater]

@evert It would be great if you could add these workarounds to avoid writing extra code. the application/json should be the default for oauth2-client, by adding that this issue will be fixed.

this line should be achieved on the getToken function too

If these headers are the default, the Accept header should be included here

[imunderwater]

one more thing OAuth2Token should be keys of unknown, We don't know the response format coming from the token endpoint.

[evert]

@evert It would be great if you could add these workarounds to avoid writing extra code. the application/json should be the default for oauth2-client, by adding that this issue will be fixed.

Yes, as I said I intend to add these workarounds.

one more thing OAuth2Token should be keys of unknown, We don't know the response format coming from the token endpoint.

OAuth2 is a standard format. We definitely do know what the format will be.

[imunderwater]

@evert how can i get the id_token from the google oauth that the auth server return?

[evert]

OpenID Connect support is out of scope for this library. I've started thinking a bit more about dealing with arbitrary properties here #145 but not sure yet how I will deal with that. Changing a type to unknown wouldn't do anything in this case.

[imunderwater]

Obtaining the actual response form is useful. I need to use the id_token and scoop, but it's not possible to do so.
it would be great if you could achieve that as well.

[imunderwater]

hey @evert, any update on extra parameters or the Accept method?, i really need this for my project.

[evert]

No update. I will get to it when I can. In the meantime you can:

1. monkeypatch this
2. fork and change it
3. submit a pull request to help move this along. If no tests failed after making this change, add a test.

if you're in a hurry 1) is probably the quickest, and you can just remove that again when this is changed in a future release.

[evert]

2 fixes are in, #152 and #153. Closing this! Thanks for the bug report.