1 files changed, 140 insertions, 0 deletions
diff --git a/modules/hcaptcha/hcaptcha.go b/modules/hcaptcha/hcaptcha.go
new file mode 100644
index 00000000..b970d491
--- /dev/null
+++ b/modules/hcaptcha/hcaptcha.go
@@ -0,0 +1,140 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hcaptcha
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+const verifyURL = "https://hcaptcha.com/siteverify"
+
+// Client is an hCaptcha client
+type Client struct {
+	ctx  context.Context
+	http *http.Client
+
+	secret string
+}
+
+// PostOptions are optional post form values
+type PostOptions struct {
+	RemoteIP string
+	Sitekey  string
+}
+
+// ClientOption is a func to modify a new Client
+type ClientOption func(*Client)
+
+// WithHTTP sets the http.Client of a Client
+func WithHTTP(httpClient *http.Client) func(*Client) {
+	return func(hClient *Client) {
+		hClient.http = httpClient
+	}
+}
+
+// WithContext sets the context.Context of a Client
+func WithContext(ctx context.Context) func(*Client) {
+	return func(hClient *Client) {
+		hClient.ctx = ctx
+	}
+}
+
+// New returns a new hCaptcha Client
+func New(secret string, options ...ClientOption) (*Client, error) {
+	if strings.TrimSpace(secret) == "" {
+		return nil, ErrMissingInputSecret
+	}
+
+	client := &Client{
+		ctx:    context.Background(),
+		http:   http.DefaultClient,
+		secret: secret,
+	}
+
+	for _, opt := range options {
+		opt(client)
+	}
+
+	return client, nil
+}
+
+// Response is an hCaptcha response
+type Response struct {
+	Success     bool        `json:"success"`
+	ChallengeTS string      `json:"challenge_ts"`
+	Hostname    string      `json:"hostname"`
+	Credit      bool        `json:"credit,omitempty"`
+	ErrorCodes  []ErrorCode `json:"error-codes"`
+}
+
+// Verify checks the response against the hCaptcha API
+func (c *Client) Verify(token string, opts PostOptions) (*Response, error) {
+	if strings.TrimSpace(token) == "" {
+		return nil, ErrMissingInputResponse
+	}
+
+	post := url.Values{
+		"secret":   []string{c.secret},
+		"response": []string{token},
+	}
+	if strings.TrimSpace(opts.RemoteIP) != "" {
+		post.Add("remoteip", opts.RemoteIP)
+	}
+	if strings.TrimSpace(opts.Sitekey) != "" {
+		post.Add("sitekey", opts.Sitekey)
+	}
+
+	// Basically a copy of http.PostForm, but with a context
+	req, err := http.NewRequestWithContext(c.ctx, http.MethodPost, verifyURL, strings.NewReader(post.Encode()))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, err
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var response *Response
+	if err := json.Unmarshal(body, &response); err != nil {
+		return nil, err
+	}
+
+	return response, nil
+}
+
+// Verify calls hCaptcha API to verify token
+func Verify(ctx context.Context, response string) (bool, error) {
+	client, err := New(setting.Service.HcaptchaSecret, WithContext(ctx))
+	if err != nil {
+		return false, err
+	}
+
+	resp, err := client.Verify(response, PostOptions{
+		Sitekey: setting.Service.HcaptchaSitekey,
+	})
+	if err != nil {
+		return false, err
+	}
+
+	var respErr error
+	if len(resp.ErrorCodes) > 0 {
+		respErr = resp.ErrorCodes[0]
+	}
+	return resp.Success, respErr
+}