made LoginHandler slightly less awful

Signed-off-by: ari melody <ari@arimelody.me>

api/v1/admin/admin.go

@@ -100,64 +100,23 @@ func LoginHandler() http.Handler {
             return
         }
 
-        // let's get an oauth token!
+        auth_token, err := discord.GetOAuthTokenFromCode(code)
-        req, err := http.NewRequest(http.MethodPost, fmt.Sprintf("%s/oauth2/token", discord.API_ENDPOINT),
-            strings.NewReader(url.Values{
-            "client_id": {discord.CLIENT_ID},
-            "client_secret": {discord.CLIENT_SECRET},
-            "grant_type": {"authorization_code"},
-            "code": {code},
-            "redirect_uri": {discord.MY_REDIRECT_URI},
-        }.Encode()))
-        req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
-
-        res, err := http.DefaultClient.Do(req)
         if err != nil {
-            fmt.Printf("Failed to retrieve OAuth token: %s\n", err)
+            fmt.Printf("Failed to retrieve discord access token: %s\n", err)
             w.WriteHeader(500)
             w.Write([]byte("Internal server error"))
             return
         }
 
-        oauth := discord.AccessTokenResponse{}
+        discord_user, err := discord.GetDiscordUserFromAuth(auth_token)
-
-        err = json.NewDecoder(res.Body).Decode(&oauth)
         if err != nil {
-            fmt.Printf("Failed to parse OAuth response data from discord: %s\n", err)
+            fmt.Printf("Failed to retrieve discord user information: %s\n", err)
-            w.WriteHeader(500)
-            w.Write([]byte("Internal server error"))
-            return
-        }
-        res.Body.Close()
-
-        discord_access_token := oauth.AccessToken
-
-        // let's get authorisation information!
-        req, err = http.NewRequest(http.MethodGet, fmt.Sprintf("%s/oauth2/@me", discord.API_ENDPOINT), nil)
-        req.Header.Add("Authorization", "Bearer " + discord_access_token)
-
-        res, err = http.DefaultClient.Do(req)
-        if err != nil {
-            fmt.Printf("Failed to retrieve discord auth information: %s\n", err)
             w.WriteHeader(500)
             w.Write([]byte("Internal server error"))
             return
         }
 
-        auth_info := discord.AuthInfoResponse{}
+        if discord_user.Id != ADMIN_ID_DISCORD {
-
-        err = json.NewDecoder(res.Body).Decode(&auth_info)
-        if err != nil {
-            fmt.Printf("Failed to parse auth information from discord: %s\n", err)
-            w.WriteHeader(500)
-            w.Write([]byte("Internal server error"))
-            return
-        }
-        res.Body.Close()
-
-        discord_user_id := auth_info.User.Id
-        
-        if discord_user_id != ADMIN_ID_DISCORD {
             // TODO: unauthorized user. revoke the token
             w.WriteHeader(401)
             w.Write([]byte("Unauthorized"))
@@ -165,7 +124,7 @@ func LoginHandler() http.Handler {
         }
 
         // login success!
-        session := CreateSession(auth_info.User.Username)
+        session := CreateSession(discord_user.Username)
         sessions = append(sessions, &session)
 
         cookie := http.Cookie{}

discord/discord.go

@@ -1,11 +1,22 @@
 package discord
 
+import (
+    "encoding/json"
+    "errors"
+    "fmt"
+    "net/http"
+    "net/url"
+    "strings"
+)
+
 const API_ENDPOINT = "https://discord.com/api/v10"
 const CLIENT_ID = "1268013769578119208"
+
 // TODO: good GOD change this later please i beg you. we've already broken
 // the rules by doing this at all
 const CLIENT_SECRET = "JUEZnixhN7BxmLIHmbECiKETMP85VT0E"
 const REDIRECT_URI = "https://discord.com/oauth2/authorize?client_id=1268013769578119208&response_type=code&redirect_uri=http%3A%2F%2F127.0.0.1%3A8080%2Fapi%2Fv1%2Fadmin%2Flogin&scope=identify"
+
 // TODO: change before prod
 const MY_REDIRECT_URI = "http://127.0.0.1:8080/api/v1/admin/login"
 
@@ -31,7 +42,10 @@ type (
         }
         Scopes  []string
         Expires string
-        User struct {
+        User    DiscordUser
+    }
+
+    DiscordUser struct {
         Id            string
         Username      string
         Avatar        string
@@ -39,6 +53,53 @@ type (
         GlobalName    string
         PublicFlags   int
     }
-    }
 )
 
+func GetOAuthTokenFromCode(code string) (string, error) {
+    // let's get an oauth token!
+    req, err := http.NewRequest(http.MethodPost, fmt.Sprintf("%s/oauth2/token", API_ENDPOINT),
+    strings.NewReader(url.Values{
+        "client_id":     {CLIENT_ID},
+        "client_secret": {CLIENT_SECRET},
+        "grant_type":    {"authorization_code"},
+        "code":          {code},
+        "redirect_uri":  {MY_REDIRECT_URI},
+    }.Encode()))
+    req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
+
+    res, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return "", errors.New(fmt.Sprintf("Failed while contacting discord API: %s", err))
+    }
+
+    oauth := AccessTokenResponse{}
+
+    err = json.NewDecoder(res.Body).Decode(&oauth)
+    if err != nil {
+        return "", errors.New(fmt.Sprintf("Failed to parse OAuth response data from discord: %s\n", err))
+    }
+    res.Body.Close()
+
+    return oauth.AccessToken, nil
+}
+
+func GetDiscordUserFromAuth(token string) (DiscordUser, error) {
+    // let's get authorisation information!
+    req, err := http.NewRequest(http.MethodGet, fmt.Sprintf("%s/oauth2/@me", API_ENDPOINT), nil)
+    req.Header.Add("Authorization", "Bearer " + token)
+
+    res, err := http.DefaultClient.Do(req)
+    if err != nil {
+        return DiscordUser{}, errors.New(fmt.Sprintf("Failed to retrieve discord auth information: %s\n", err))
+    }
+
+    auth_info := AuthInfoResponse{}
+
+    err = json.NewDecoder(res.Body).Decode(&auth_info)
+    if err != nil {
+        return DiscordUser{}, errors.New(fmt.Sprintf("Failed to parse auth information from discord: %s\n", err))
+    }
+    defer res.Body.Close()
+
+    return auth_info.User, nil
+}