feat: added captcha serving service to haproxy

scripts/hcaptcha.lua

@@ -0,0 +1,51 @@
+hcaptcha = {}
+
+local url = require("net.url")
+local https = require("ssl.https")
+local json = require("json")
+
+function hcaptcha.view(applet)
+    local hcaptcha_secret = os.getenv("HCAPTCHA_SECRET")
+    local hcaptcha_sitekey = os.getenv("HCAPTCHA_SITEKEY")
+
+    local response
+    if applet.method == "GET" then
+        response =
+            [[
+        <form method="POST">
+        <div class="h-captcha" data-sitekey="%s"></div>
+        <script src="https://hcaptcha.com/1/api.js" async defer></script>
+        <input type="submit" value="Submit">
+        </form>
+        ]]
+        response = string.format(response, hcaptcha_sitekey)
+    elseif applet.method == "POST" then
+        local parsed_body = url.parseQuery(applet.receive(applet))
+
+        if parsed_body["h-captcha-response"] then
+            local url =
+                string.format(
+                "https://hcaptcha.com/siteverify?secret=%s&response=%s",
+                hcaptcha_secret,
+                parsed_body["h-captcha-response"]
+            )
+            local body, code, headers, status = https.request(url)
+            local api_response = json:decode(body)
+
+            if api_response.success == true then
+                print("HCAPTCHA SUCCESSFULLY PASSED")
+                print("... success captcha flow goes here ...")
+            else
+                print("HCAPTCHA FAILED", body)
+            end
+        end
+
+        response = "Thank you for submitting"
+    end
+
+    applet:set_status(200)
+    applet:add_header("content-type", "text/html")
+    applet:add_header("content-length", string.len(response))
+    applet:start_response()
+    applet:send(response)
+end