Files
Gitea/services/context/captcha.go
lif 4ed43c2a32 fix: Improve image captcha contrast for dark mode (#36265)
## Summary
This PR fixes #36255

The image captcha was using random colors which often resulted in poor
contrast against dark backgrounds, making it difficult or impossible for
users to read in dark mode.

## Changes
- Added a custom color palette to the image captcha configuration in
`services/context/captcha.go`
- The palette uses high-contrast colors (bright red, blue, green,
yellow, purple, and dark blue-gray) that provide good visibility in both
light and dark themes
- This improves accessibility and user experience without changing any
existing functionality

## Testing
- Builds successfully
- All existing tests pass
- The color palette is properly supported by the upstream
`gitea.com/go-chi/captcha` library

---
Generated with Claude Code

---------

Signed-off-by: majiayu000 <1835304752@qq.com>
Co-authored-by: silverwind <me@silverwind.io>
2026-01-24 05:41:51 +00:00

104 lines
3.2 KiB
Go

// Copyright 2020 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package context
import (
"fmt"
"image/color"
"sync"
"code.gitea.io/gitea/modules/cache"
"code.gitea.io/gitea/modules/hcaptcha"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/mcaptcha"
"code.gitea.io/gitea/modules/recaptcha"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/templates"
"code.gitea.io/gitea/modules/turnstile"
"gitea.com/go-chi/captcha"
)
var (
imageCaptchaOnce sync.Once
cpt *captcha.Captcha
)
// GetImageCaptcha returns global image captcha
func GetImageCaptcha() *captcha.Captcha {
imageCaptchaOnce.Do(func() {
cpt = captcha.NewCaptcha(captcha.Options{
SubURL: setting.AppSubURL,
// Use a color palette with high contrast colors suitable for both light and dark modes
// These colors provide good visibility and readability in both themes
ColorPalette: color.Palette{
color.RGBA{R: 234, G: 67, B: 53, A: 255}, // Bright red
color.RGBA{R: 66, G: 133, B: 244, A: 255}, // Medium blue
color.RGBA{R: 52, G: 168, B: 83, A: 255}, // Green
color.RGBA{R: 251, G: 188, B: 5, A: 255}, // Yellow/gold
color.RGBA{R: 171, G: 71, B: 188, A: 255}, // Purple
},
})
cpt.Store = cache.GetCache().ChiCache()
})
return cpt
}
// SetCaptchaData sets common captcha data
func SetCaptchaData(ctx *Context) {
if !setting.Service.EnableCaptcha {
return
}
ctx.Data["EnableCaptcha"] = setting.Service.EnableCaptcha
ctx.Data["RecaptchaURL"] = setting.Service.RecaptchaURL
ctx.Data["Captcha"] = GetImageCaptcha()
ctx.Data["CaptchaType"] = setting.Service.CaptchaType
ctx.Data["RecaptchaSitekey"] = setting.Service.RecaptchaSitekey
ctx.Data["HcaptchaSitekey"] = setting.Service.HcaptchaSitekey
ctx.Data["McaptchaSitekey"] = setting.Service.McaptchaSitekey
ctx.Data["McaptchaURL"] = setting.Service.McaptchaURL
ctx.Data["CfTurnstileSitekey"] = setting.Service.CfTurnstileSitekey
}
const (
gRecaptchaResponseField = "g-recaptcha-response"
hCaptchaResponseField = "h-captcha-response"
mCaptchaResponseField = "m-captcha-response"
cfTurnstileResponseField = "cf-turnstile-response"
)
// VerifyCaptcha verifies Captcha data
// No-op if captchas are not enabled
func VerifyCaptcha(ctx *Context, tpl templates.TplName, form any) {
if !setting.Service.EnableCaptcha {
return
}
var valid bool
var err error
switch setting.Service.CaptchaType {
case setting.ImageCaptcha:
valid = GetImageCaptcha().VerifyReq(ctx.Req)
case setting.ReCaptcha:
valid, err = recaptcha.Verify(ctx, ctx.Req.Form.Get(gRecaptchaResponseField))
case setting.HCaptcha:
valid, err = hcaptcha.Verify(ctx, ctx.Req.Form.Get(hCaptchaResponseField))
case setting.MCaptcha:
valid, err = mcaptcha.Verify(ctx, ctx.Req.Form.Get(mCaptchaResponseField))
case setting.CfTurnstile:
valid, err = turnstile.Verify(ctx, ctx.Req.Form.Get(cfTurnstileResponseField))
default:
ctx.ServerError("Unknown Captcha Type", fmt.Errorf("unknown Captcha Type: %s", setting.Service.CaptchaType))
return
}
if err != nil {
log.Debug("Captcha Verify failed: %v", err)
}
if !valid {
ctx.Data["Err_Captcha"] = true
ctx.RenderWithErr(ctx.Tr("form.captcha_incorrect"), tpl, form)
}
}