api: add github oauth

Closes https://gitlab.com/commento/commento/issues/20
2019-01-30 21:15:16 -05:00
parent 24d76c2fb6
commit 55f24b2de2
8 changed files with 200 additions and 1 deletions
--- a/api/oauth_github_callback.go
+++ b/api/oauth_github_callback.go
@@ -0,0 +1,115 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"golang.org/x/oauth2"
+	"io/ioutil"
+	"net/http"
+)
+
+func githubGetPrimaryEmail(accessToken string) (string, error) {
+	resp, err := http.Get("https://api.github.com/user/emails?access_token=" + accessToken)
+	defer resp.Body.Close()
+
+	contents, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return "",  errorCannotReadResponse
+	}
+
+	user := []map[string]interface{}{}
+	if err := json.Unmarshal(contents, &user); err != nil {
+		logger.Errorf("error unmarshaling github user: %v", err)
+		return "", errorInternal
+	}
+
+	nonPrimaryEmail := ""
+	for _, email := range(user) {
+		nonPrimaryEmail = email["email"].(string)
+		if email["primary"].(bool) {
+			return email["email"].(string), nil
+		}
+	}
+
+	return nonPrimaryEmail, nil
+}
+
+func githubCallbackHandler(w http.ResponseWriter, r *http.Request) {
+	commenterToken := r.FormValue("state")
+	code := r.FormValue("code")
+
+	_, err := commenterGetByCommenterToken(commenterToken)
+	if err != nil && err != errorNoSuchToken {
+		fmt.Fprintf(w, "Error: %s\n", err.Error())
+		return
+	}
+
+	token, err := githubConfig.Exchange(oauth2.NoContext, code)
+	if err != nil {
+		fmt.Fprintf(w, "Error: %s", err.Error())
+		return
+	}
+
+	email, err := githubGetPrimaryEmail(token.AccessToken)
+	if err != nil {
+		fmt.Fprintf(w, "Error: %s", err.Error())
+		return
+	}
+
+	resp, err := http.Get("https://api.github.com/user?access_token=" + token.AccessToken)
+	defer resp.Body.Close()
+
+	contents, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Fprintf(w, "Error: %s", errorCannotReadResponse.Error())
+		return
+	}
+
+	user := make(map[string]interface{})
+	if err := json.Unmarshal(contents, &user); err != nil {
+		fmt.Fprintf(w, "Error: %s", errorInternal.Error())
+		return
+	}
+
+	if email == "" {
+		if user["email"] == nil {
+			fmt.Fprintf(w, "Error: no email address returned by Github")
+			return
+		}
+
+		email = user["email"].(string)
+	}
+
+	c, err := commenterGetByEmail("github", email)
+	if err != nil && err != errorNoSuchCommenter {
+		fmt.Fprintf(w, "Error: %s", err.Error())
+		return
+	}
+
+	var commenterHex string
+
+	// TODO: in case of returning users, update the information we have on record?
+	if err == errorNoSuchCommenter {
+		var link string
+		if val, ok := user["html_url"]; ok {
+			link = val.(string)
+		} else {
+			link = "undefined"
+		}
+
+		commenterHex, err = commenterNew(email, user["name"].(string), link, user["avatar_url"].(string), "github", "")
+		if err != nil {
+			fmt.Fprintf(w, "Error: %s", err.Error())
+			return
+		}
+	} else {
+		commenterHex = c.CommenterHex
+	}
+
+	if err := commenterSessionUpdate(commenterToken, commenterHex); err != nil {
+		fmt.Fprintf(w, "Error: %s", err.Error())
+		return
+	}
+
+	fmt.Fprintf(w, "<html><script>window.parent.close()</script></html>")
+}