Captcha Provider

This section analyzes the core source code of the module a-captchasimple to illustrate how to develop a new Captcha Provider

Creating a Captcha Provider

For example, creating a Captcha Provider: imageText within the module a-captchasimple

1. CLI Command

$ vona :create:bean captchaProvider imageText --module=a-captchasimple

2. Menu Command

TIP

Context Menu - [Module Path]: Vona Bean/Captcha Provider

Captcha Provider Definition

export type TypeCaptchaProviderImageTextToken = string;
export type TypeCaptchaProviderImageTextPayload = string;
export type TypeCaptchaProviderImageTextData = ICaptchaProviderData<TypeCaptchaProviderImageTextToken, TypeCaptchaProviderImageTextPayload>;

export type TypeCaptchaProviderImageTextType = 'char' | 'math';
const CaptchaProviderImageTextTypes = ['char', 'math'] as const;
export interface ICaptchaProviderOptionsImageText extends IDecoratorCaptchaProviderOptions {
  type?: TypeCaptchaProviderImageTextType;
  fontPath?: string;
  opts: ConfigObject;
}

@CaptchaProvider<ICaptchaProviderOptionsImageText>({
  opts: {
    size: 4,
    color: true,
  },
})
class CaptchaProviderImageText {
  async create(options) {
    this._confirmFont(options);
    let type = options.type;
    if (!type) {
      type = CaptchaProviderImageTextTypes[getRandomInt(2, 0)];
    }
    const captcha = type === 'char' ? svgCaptcha.create(options.opts) : svgCaptcha.createMathExpr(options.opts);
    return { token: captcha.text, payload: svg64(captcha.data) };
  }

  async verify(
    token,
    tokenInput,
    _options,
  ) {
    return !!tokenInput && !!token && tokenInput.toLowerCase() === token.toLowerCase();
  }
}

• TypeCaptchaProviderImageTextToken: Token type; different providers may have different token types

• TypeCaptchaProviderImageTextPayload: Payload type; different providers may have different payload types

• TypeCaptchaProviderImageTextData: Captcha Data type corresponding to the current provider

• ICaptchaProviderOptionsImageText: Parameters of the current provider. Different providers can offer different parameter configurations. For example, this provider implements image-text Captcha capabilities based on svg-captcha, therefore it provides the following parameters required by svg-captcha: type/fontPath/opts

• create: Creates captcha data

• verify: Verifies the captcha token's correctness

App Config

Captcha Provider parameters can be configured in the App Config

src/backend/config/config/config.ts

// onions
config.onions = {
  captchaProvider: {
    'a-captchasimple:imageText': {
      type: 'char',
      opts: {
        size: 4,
        color: true,
      },
    },
  },
};