[](https://github.com/ykurtbas/elixir-finger/actions/workflows/elixir.yml)
# Finger
Finger is a verification library - captcha - to prove hommaannnnnness of a `user`.
Finger achieves this by showing pictures of N hands holding up random fingers and asking users to verify how many fingers am I holding up, which is a task our machine friends suck at!
```elixir
{answer, image} = Finger.generate(N)
```
- `answer` is the string answer to the challenge
- `image` is the binary challenge image to be displayed to the user
You can see the Finger output with the following examples. Please not that rest of the form fields are generated by the application not the library.
The answer would be `2025`
The answer would be `2543`
## Context and Demo
* More detailed blog [post](https://elxsy.com/blog/giving-the-finger-to-those-pesky-bots)
* You can see it in action [on the registration page for elxsy](https://elxsy.com/users/register)
** Please do not sign up if you do not intend to pass the email verification :)
## Dependencies
This library requires the awesome [imagemagick](https://imagemagick.org/) software to be installed on your machine. It is not version dependant.
## Improvements
Lot's of imporevements to be made to the library itself. First elixir and hex package, please bare with me :)
- Maybe fetch the asset paths once rather than everytime?
- Error case improvements
- unit testing System.Cmd
- unit testing Docs
## Installation
Install from Hex
```elixir
def deps do
[
{:finger, "~> 0.1.3"}
]
end
```
## Getting Started
1. Create an `action` to display the image
```elixir
defmodule Elxsy.TestController do
use Elxsy, :controller
...
def test(conn, _params) do
...
render(conn, ....)
end
def finger(conn, _params) do
{answer, image} = Finger.generate()
# store the answer in session or somwhere else on the server side
conn
|> put_session(:fingers, answer)
|> put_resp_content_type("image/jpeg")
|> send_resp(200, image)
end
def verify(conn, params) do
answer = get_session(conn, :fingers)
delete_session(conn, :fingers)
if params["fingers"] === answer do
...
end
end
end
```
2. Add to your routes
```elixir
get "/test/finger.jpg", TestController, :finger
```
3. Add to your template for `test` action
```elixir
...
<img src="<%= Routes.test_path(@conn, :finger) %>" />
<input type="number" name="fingers" placeholder="Please tell me how many fingers are shown in each hand" required="true" />
...
```
4. Verify for the answer in form submission with the `verify` like the example.
## Library
Documentation can be found within the code and methods itself as well as hexdocs but the important highlight.
```
Default number of images is: 4
Minimum number of images is: 2 (inclusive)
Maximum number of images is: 9 (inclusive)
```
## Contribution to the library
Please fork and make necessary changes, raise a pull request.
## Contribution to the picture stack
More the merrier!
- Fork the project
- Please take a _SQUARE_ picture of your hand holding some fingers up - respectfully
- Either facing your palm or back of your hand
- With decent lighting and exposure
- On a mixed background like nature or some furniture with patterns. Please *avoid* clear, flat walls and plain backgrounds.
- Resize to 200x200
- name the picture as `{finger_count}_{YYMMDD}_{github_username}.jpg` ie, if I am showing 2 fingers up, it would be `2_210408_ykurtbas.jpg`
- commit into `assets` folder
- Raise a pull request.
## Bugs or Issues
- Please raise a bug or issue request in the tracker
