You can consider this post as sort of a public notebook. I started this since I've recently started dabbling with Notion's API and stumbled across some things I wanted to take note of, should I ever run into them again.
Content-Type is important
If you interact with Notion's API, never forget to set the Content-Type
header to application/json. Otherwise you'll get errors that you'll spend
hours debugging. I, for example called the
https://api.notion.com/v1/oauth/token endpoint to exchange an auth code for a
more permanent OAuth token.
And while I sent the following body:
{
grant_type: 'authorization_code',
code: 'temporary auth code you get as request parameter',
redirect_uri: 'where your OAuth callback lives'
}
I always received a 400 error with a message stating I need to send a
grant_type. Turns out that Notion doesn't really parse your request body when
you don't send along Content-Type: application/json, and the error message is
less than ideal.
A better response would've been a 415 Unsupported Media Type error with a message stating that Notion only accepts JSON data.