sponsors.go - query whether a GitHub user is your sponsor at a given tier (dollar amount)

sponsors.go

// LICENSE for this file: MIT
// Copyright: Alex Ellis, OpenFaaS Ltd 2020
// You may not remove this notice
package handlers

import (
	"context"
	"encoding/json"
	"os"

	"github.com/shurcooL/githubv4"
	"golang.org/x/oauth2"
)

const minDollars = 25

type SponsorTier struct {
	MonthlyPriceInDollars int
}

// SponsorEntity is the User sponsoring
type SponsorEntity struct {
	// SponsorUser with an annotation that expands the Union for the User type
	SponsorUser SponsorUser `graphql:"... on User"`
}

// Sponsorable is the User receiving the sponsorshop
type Sponsorable struct {
	// SponsorUser with an annotation that expands the Union for the User type
	SponsorUser SponsorUser `graphql:"... on User"`
}

// SponsorUser is a User associated with either side of a
// sponsorship
type SponsorUser struct {
	// Login name of the sponsor.
	Login string
}

// IsSponsoring returns true if the login for the associated
// accessToken has an active sponsorship for the target login of
// the hard-coded dollar amount.
// The accessToken requires the whole "user" scope to read the
// dollar amount.
func IsSponsoring(login, target, accessToken string) (bool, error) {
	// it's not possible to sponsor oneself
	if login == target {
		return true, nil
	}

	src := oauth2.StaticTokenSource(
		&oauth2.Token{AccessToken: accessToken},
	)

	httpClient := oauth2.NewClient(context.Background(), src)
	client := githubv4.NewClient(httpClient)

	var q sponsorships

	ctx := context.Background()
	err := client.Query(ctx, &q, map[string]interface{}{})

	if err != nil {
		return false, err
	}

	// printJSON(q.Viewer.SponsorshipsAsSponsor.Nodes)
	var users []SponsorUser
	for _, node := range q.Viewer.SponsorshipsAsSponsor.Nodes {
		sponsor := node.SponsorEntity.SponsorUser

		if node.Sponsorable.SponsorUser.Login == target &&
			node.Tier.MonthlyPriceInDollars >= minDollars {
			users = append(users, sponsor)
		}
	}

	for _, s := range users {
		if s.Login == login {
			return true, nil
		}
	}

	return false, nil
}

// sponsorships is the query for graphql and it limits
// the search to 100, since most people will not be
// sponsoring more than a few other developers.
type sponsorships struct {
	Viewer struct {
		Login                 string
		SponsorshipsAsSponsor struct {
			Nodes []struct {
				SponsorEntity SponsorEntity
				Sponsorable   Sponsorable
				Tier          SponsorTier
			}
		} `graphql:"sponsorshipsAsSponsor(first: 100)"`
	}
}

// printJSON is from the github.com/shurcooL/githubv4 library
// and prints the response for debugging.
func printJSON(v interface{}) {
	w := json.NewEncoder(os.Stdout)
	w.SetIndent("", "\t")
	err := w.Encode(v)
	if err != nil {
		panic(err)
	}
}