Ref [Authorization Code Flow for Server-side Apps](https://developer.yahoo.com/oauth2/guide/flows_authcode/)
1. 
https://developer.yahoo.com/apps/
```
Application Name: oauth2-rs-demo
Redirect URI(s): https://oauth2-rs.lvh.me/auth/yahoo/callback
API Permissions:
```
```
Client ID: x*96
Client Secret: x*40
```