implement recaptcha on login

Former-commit-id: d7495b6fff4a99a8d155a3be87b15535a74a1305 [formerly 5b3a544447cca0d1cdcb6c87ca94f450a5493506] [formerly b4de1a4f5d4dd295c98366ede2b87bf2cb7918f9 [formerly 002f8066c794c9c440ec437743f6ddfa864f976b]]
Former-commit-id: c0e5d38111a99f8e3e71fb5db86e19b7ba44ec48 [formerly 1b5e454263ba64ced95c6d4b51f5f32e66f74758]
Former-commit-id: cfb17a53fc86d0071fba91503502444f5f10a0c7

http/auth.go

@@ -1,8 +1,11 @@
 package http
 
 import (
+	"bytes"
 	"encoding/json"
+	"fmt"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 
@@ -11,6 +14,45 @@ import (
 	fm "github.com/hacdias/filemanager"
 )
 
+type cred struct {
+	Password  string `json:"password"`
+	Username  string `json:"username"`
+	Recaptcha string `json:"recaptcha"`
+}
+
+// recaptcha checks the recaptcha code.
+func recaptcha(secret string, response string) (bool, error) {
+	api := "https://www.google.com/recaptcha/api/siteverify"
+
+	body := url.Values{}
+	body.Set("secret", secret)
+	body.Add("response", response)
+
+	client := &http.Client{}
+	resp, err := client.Post(api, "application/x-www-form-urlencoded", bytes.NewBufferString(body.Encode()))
+	if err != nil {
+		return false, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return false, nil
+	}
+
+	var data struct {
+		Success     bool        `json:"success"`
+		ChallengeTS time.Time   `json:"challenge_ts"`
+		Hostname    string      `json:"hostname"`
+		ErrorCodes  interface{} `json:"error-codes"`
+	}
+
+	err = json.NewDecoder(resp.Body).Decode(&data)
+	if err != nil {
+		return false, err
+	}
+
+	return data.Success, nil
+}
+
 // authHandler proccesses the authentication for the user.
 func authHandler(c *fm.Context, w http.ResponseWriter, r *http.Request) (int, error) {
 	// NoAuth instances shouldn't call this method.
@@ -19,7 +61,7 @@ func authHandler(c *fm.Context, w http.ResponseWriter, r *http.Request) (int, er
 	}
 
 	// Receive the credentials from the request and unmarshal them.
-	var cred fm.User
+	var cred cred
 	if r.Body == nil {
 		return http.StatusForbidden, nil
 	}
@@ -29,6 +71,19 @@ func authHandler(c *fm.Context, w http.ResponseWriter, r *http.Request) (int, er
 		return http.StatusForbidden, nil
 	}
 
+	// If ReCaptcha is enabled, check the code.
+	if len(c.ReCaptchaSecret) > 0 {
+		ok, err := recaptcha(c.ReCaptchaSecret, cred.Recaptcha)
+		if err != nil {
+			fmt.Println(err)
+			return http.StatusForbidden, err
+		}
+
+		if !ok {
+			return http.StatusForbidden, nil
+		}
+	}
+
 	// Checks if the user exists.
 	u, err := c.Store.Users.GetByUsername(cred.Username, c.NewFS)
 	if err != nil {

http/http.go

@@ -226,10 +226,13 @@ func renderFile(c *fm.Context, w http.ResponseWriter, file string) (int, error)
 	w.Header().Set("Content-Type", contentType+"; charset=utf-8")
 
 	data := map[string]interface{}{
-		"BaseURL": c.RootURL(),
-		"NoAuth":  c.NoAuth,
-		"Version": fm.Version,
-		"CSS":     template.CSS(c.CSS),
+		"BaseURL":         c.RootURL(),
+		"NoAuth":          c.NoAuth,
+		"Version":         fm.Version,
+		"CSS":             template.CSS(c.CSS),
+		"ReCaptcha":       c.ReCaptchaKey != "" && c.ReCaptchaSecret != "",
+		"ReCaptchaKey":    c.ReCaptchaKey,
+		"ReCaptchaSecret": c.ReCaptchaSecret,
 	}
 
 	if c.StaticGen != nil {