games/factorio/modproxy/modportal/modportal.go

package modportal

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"

	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

type Mod struct {
	Name     string    `json:"name"`
	Releases []Release `json:"releases"`
}

type Release struct {
	DownloadURL string   `json:"download_url"`
	FileName    string   `json:"file_name"`
	Info        InfoJSON `json:"info_json"`
	ReleasedAt  string   `json:"released_at"`
	SHA1        string   `json:"sha1"`
	Version     string   `json:"version"`
}

type InfoJSON struct {
	Dependencies    []string `json:"dependencies"`
	FactorioVersion string   `json:"factorio_json"`
}

func GetMod(ctx context.Context, name string) (*Mod, error) {
	url := fmt.Sprintf("https://mods.factorio.com/api/mods/%s", url.PathEscape(name))

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "NewRequest(%q): %v", url, err)
	}

	req = req.WithContext(ctx)
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, status.Errorf(codes.Unavailable, "Do(req{%q}): %v", url, err)
	}
	defer res.Body.Close()

	if res.StatusCode != 200 {
		return nil, status.Errorf(codes.Unavailable, "mod portal responded with code: %d", res.StatusCode)
	}

	mod := &Mod{}
	err = json.NewDecoder(res.Body).Decode(mod)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "could not decode mod portal JSON: %v", err)
	}

	return mod, nil
}

func (m *Mod) ReleaseBySHA1(sha1 string) *Release {
	for _, r := range m.Releases {
		if r.SHA1 == sha1 {
			return &r
		}
	}
	return nil
}

func (m *Mod) ReleaseByVersion(version string) *Release {
	for _, r := range m.Releases {
		if r.Version == version {
			return &r
		}
	}
	return nil
}

func (r *Release) Download(ctx context.Context, username, token string) (io.ReadCloser, error) {
	url := fmt.Sprintf("https://mods.factorio.com/%s?username=%s&token=%s", r.DownloadURL, username, token)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "NewRequest(%q): %v", url, err)
	}

	req = req.WithContext(ctx)
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, status.Errorf(codes.Unavailable, "Do(req{%q}): %v", url, err)
	}
	if res.StatusCode != 200 {
		res.Body.Close()
		return nil, status.Errorf(codes.Unavailable, "mod portal responded with code: %d", res.StatusCode)
	}

	return res.Body, err
}