Overleaf/services/web/app/coffee/Features/Captcha/CaptchaMiddleware.coffee

request = require 'request'
logger = require 'logger-sharelatex'
Settings = require 'settings-sharelatex'

module.exports = CaptchaMiddleware =
	validateCaptcha: (action) ->
		return (req, res, next) ->
			if !Settings.recaptcha?.siteKey?
				return next()
			inviteAndCaptchaDisabled = action == 'invite' and Settings.recaptcha.disabled.invite
			registerAndCaptchaDisabled = action == 'register' and Settings.recaptcha.disabled.register
			if inviteAndCaptchaDisabled or registerAndCaptchaDisabled
				return next()
			response = req.body['g-recaptcha-response']
			options =
				form:
					secret: Settings.recaptcha.secretKey
					response: response
				json: true
			request.post "https://www.google.com/recaptcha/api/siteverify", options, (error, response, body) ->
				return next(error) if error?
				if !body?.success
					logger.warn {statusCode: response.statusCode, body: body}, 'failed recaptcha siteverify request'
					return res.status(400).send({errorReason:"cannot_verify_user_not_robot", message:
						{text:"Sorry, we could not verify that you are not a robot. Please check that Google reCAPTCHA is not being blocked by an ad blocker or firewall."}
					})
				else
					return next()