jansvabik/fiber-recaptcha

package recaptcha

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "net/http"
    "net/url"

    "github.com/gofiber/fiber/v2"
)

// request is a structure for extracting g-recaptcha-response field from request
type request struct {
    GRecaptchaResponse string `json:"g-recaptcha-response" form:"g-recaptcha-response"`
}

// googleResponse is a structure with Google validation response data
type googleResponse struct {
    Success    bool     `json:"success"`
    Hostname   string   `json:"hostname"`
    ErrorCodes []string `json:"error-codes"`
}

// SecretKey stores the secret key for your reCAPTCHA. You can get your keys
// here: https://www.google.com/recaptcha/admin/
var SecretKey string

// validates sends the request to the Google API server and gets the results
// about the whole recaptcha process, that means the boolean value which is
// then returned from this function to be processed
func validate(grr string, ip string) (bool, error) {
    // google validation request data
    postURL := "https://www.google.com/recaptcha/api/siteverify"
    postStr := url.Values{
        "secret":   {SecretKey},
        "response": {grr},
        "remoteip": {ip},
    }

    // validity check
    responsePost, err := http.PostForm(postURL, postStr)
    if err != nil {
        return false, err
    }
    defer responsePost.Body.Close()
    body, err := ioutil.ReadAll(responsePost.Body)
    if err != nil {
        return false, err
    }

    // unmarshal the response and test the success
    gres := googleResponse{}
    json.Unmarshal(body, &gres)
    if !gres.Success {
        return false, nil
    }

    return true, nil
}

// Middleware is a fiber middleware for validating recaptchas
func Middleware(c *fiber.Ctx) error {
    // g-recaptcha-response field extraction and testing
    req := request{}
    c.BodyParser(&req)
    if req.GRecaptchaResponse == "" {
        c.Locals("recaptchaSuccess", false)
        return c.Next()
    }

    // get the google validation success value (true = success)
    ok, err := validate(req.GRecaptchaResponse, c.IP())
    if err != nil {
        fmt.Println(err.Error())
    }

    // store the result and execute the next method in router
    c.Locals("recaptchaSuccess", ok)
    return c.Next()
}