Puberty commit

backend/api/github/github.go

@@ -0,0 +1,91 @@
+package github
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+
+	"github.com/juju/errors"
+
+	"github.com/localhots/cmdui/backend/config"
+)
+
+type User struct {
+	ID      uint   `json:"id"`
+	Login   string `json:"login"`
+	Name    string `json:"name"`
+	Picture string `json:"avatar_url"`
+}
+
+const (
+	authorizeURL   = "https://github.com/login/oauth/authorize"
+	accessTokenURL = "https://github.com/login/oauth/access_token"
+	userDetailsURL = "https://api.github.com/user"
+)
+
+func RedirectToLogin(w http.ResponseWriter, r *http.Request) {
+	urlStr := authorizeURL + "?" + url.Values{
+		"client_id": {config.Get().Github.ClientID},
+		"scope":     {"user"},
+	}.Encode()
+	http.Redirect(w, r, urlStr, http.StatusTemporaryRedirect)
+}
+
+func ExchangeCode(ctx context.Context, code string) (accessToken string, err error) {
+	cfg := config.Get()
+	reqBody := bytes.NewBufferString(url.Values{
+		"client_id":     {cfg.Github.ClientID},
+		"client_secret": {cfg.Github.ClientSecret},
+		"code":          {code},
+	}.Encode())
+	req, err := http.NewRequest(http.MethodPost, accessTokenURL, reqBody)
+	if err != nil {
+		return "", errors.Annotate(err, "Failed to create a code exchange request")
+	}
+
+	// Passing client request context
+	req = req.WithContext(ctx)
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return "", errors.Annotate(err, "Failed to perform code exchange request")
+	}
+	defer resp.Body.Close()
+
+	respBody, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "", errors.Annotate(err, "Failed to read access token response")
+	}
+
+	uri, err := url.ParseQuery(string(respBody))
+	if err != nil {
+		return "", errors.Annotate(err, "Failed to parse access token response")
+	}
+
+	return uri.Get("access_token"), nil
+}
+
+func AuthDetails(accessToken string) (User, error) {
+	var u User
+	reqURL := userDetailsURL + "?" + url.Values{
+		"access_token": {accessToken},
+	}.Encode()
+	resp, err := http.Get(reqURL)
+	if err != nil {
+		return u, errors.Annotate(err, "Failed to fetch authenticated user details")
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return u, errors.Annotate(err, "Failed to read authenticated user details")
+	}
+	if err := json.Unmarshal(body, &u); err != nil {
+		return u, errors.Annotate(err, "Failed to parse authenticated user details")
+	}
+
+	return u, nil
+}