recaptcha

# Recaptcha
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A simple Elixir package for implementing [reCAPTCHA] in Elixir applications.
[reCAPTCHA]: http://www.google.com/recaptcha
## Migration from 1.x
### Breaking Changes
1. Template functionality is now in a separate module: `Recaptcha.Template`. Please note: in future templating may move to a Phoenix specific package.
2. `verify` API has changed, see the code for documentation of the new API.
Most other questions about 2.x should be answered by looking over the documentation and the code. Please raise an issue
if you have any problems with migrating.
## Installation
Add `:recaptcha` to your `mix.exs` dependencies:
```elixir
  defp deps do
    [
      {:recaptcha, "~> 3.0"},
    ]
  end
```
List `:recaptcha` as an application dependency:
```elixir
  def application do
    [
      extra_applications: [:recaptcha]
    ]
  end
```
Run `mix do deps.get, compile`
## Config
By default the public and private keys are loaded via the `RECAPTCHA_PUBLIC_KEY` and `RECAPTCHA_PRIVATE_KEY` environment variables.
```elixir
config :recaptcha,
  public_key: {:system, "RECAPTCHA_PUBLIC_KEY"},
  secret: {:system, "RECAPTCHA_PRIVATE_KEY"}
```
### JSON Decoding
By default `reCaptcha` will use `Jason` to decode JSON responses, this can be changed as such:
```elixir
config :recaptcha, :json_library, Poison
```
## Usage
### Render the Widget
Use `raw` (if you're using Phoenix.HTML) and `Recaptcha.Template.display/1` methods to render the captcha widget.
For recaptcha with checkbox:
```html
<form name="someform" method="post" action="/somewhere">
  ...
  <%= raw Recaptcha.Template.display %>
  ...
</form>
```
For invisible recaptcha:
```html
<form name="someform" method="post" action="/somewhere">
  ...
  <%= raw Recaptcha.Template.display(size: "invisible") %>
</form>
  ...
```
To change the position of the invisible recaptcha, use an option badge. See https://developers.google.com/recaptcha/docs/invisible on the date-badge.
Since recaptcha loads JavaScript code asynchronously, you cannot immediately submit the captcha form.
If you have logic that needs to know if the captcha code has already been loaded (for example disabling submit button until fully loaded), it is possible to pass in a JS-callback that will be called once the captcha has finished loading.
This can be done as follows:
```html
<form name="someform" method="post" action="/somewhere">
  ...
  <%= raw Recaptcha.Template.display(onload: "myOnLoadCallback") %>
</form>
  ...
```
And then in your JS code:
```javascript
function myOnLoadCallback() {
  // perform extra actions here
}
```
`display` method accepts additional options as a keyword list, the options are:
Option                  | Action                                                 | Default
:---------------------- | :----------------------------------------------------- | :------------------------
`noscript`              | Renders default noscript code provided by google       | `false`
`public_key`            | Sets key to the `data-sitekey` reCaptcha div attribute | Public key from the config file
`hl`                    | Sets the language of the reCaptcha                     | en
### Verify API
Recaptcha provides the `verify/2` method. Below is an example using a Phoenix controller action:
```elixir
def create(conn, params) do
  case Recaptcha.verify(params["g-recaptcha-response"]) do
    {:ok, response} -> do_something
    {:error, errors} -> handle_error
  end
end
```
`verify` method sends a `POST` request to the reCAPTCHA API and returns 2 possible values:
`{:ok, %Recaptcha.Response{challenge_ts: timestamp, hostname: host}}` -> The captcha is valid, see the [documentation](https://developers.google.com/recaptcha/docs/verify#api-response) for more details.
`{:error, errors}` -> `errors` contains atomised versions of the errors returned by the API, See the [error documentation](https://developers.google.com/recaptcha/docs/verify#error-code-reference) for more details. Errors caused by timeouts in HTTPoison or Jason encoding are also returned as atoms. If the recaptcha request succeeds but the challenge is failed, a `:challenge_failed` error is returned.
`verify` method also accepts a keyword list as the third parameter with the following options:
Option                  | Action                                                 | Default
:---------------------- | :----------------------------------------------------- | :------------------------
`timeout`               | Time to wait before timeout                            | 5000 (ms)
`secret`                | Private key to send as a parameter of the API request  | Private key from the config file
`remote_ip`             | Optional. The user's IP address, used by reCaptcha     | no default
## Testing
In order to test your endpoints you should set the secret key to the following value in order to receive a positive result from all queries to the Recaptcha engine.
```elixir
config :recaptcha,
  secret: "6LeIxAcTAAAAAGG-vFI1TnRWxMZNFuojJ4WifJWe"
```
Setting up tests without network access can be done also. When configured as such a positive or negative result can be generated locally.
```elixir
config :recaptcha,
  http_client: Recaptcha.Http.MockClient,
  secret: "6LeIxAcTAAAAAGG-vFI1TnRWxMZNFuojJ4WifJWe"
  {:ok, _details} = Recaptcha.verify("valid_response")
  {:error, _details} = Recaptcha.verify("invalid_response")
```
## Contributing
Check out [CONTRIBUTING.md](/CONTRIBUTING.md) if you want to help.
## Copyright and License
Copyright (c) 2016 Samuel Seay
This library is released under the MIT License. See the [LICENSE.md](./LICENSE.md) file
for further details.