https://github.com/willfarrell/middy-ajv
A faster and leaner alternative to @middy/validator
https://github.com/willfarrell/middy-ajv
Last synced: 10 months ago
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A faster and leaner alternative to @middy/validator
- Host: GitHub
- URL: https://github.com/willfarrell/middy-ajv
- Owner: willfarrell
- License: mit
- Created: 2021-06-05T23:39:13.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2022-10-15T03:51:33.000Z (over 3 years ago)
- Last Synced: 2025-04-01T15:48:03.159Z (11 months ago)
- Language: JavaScript
- Homepage:
- Size: 95.7 KB
- Stars: 2
- Watchers: 2
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Middy AJV
AJV middleware for the middy framework, the stylish Node.js middleware engine for AWS Lambda
This middleware automatically validates incoming events and outgoing responses against custom
schemas defined with the [JSON schema syntax](http://json-schema.org/).
If an incoming event fails validation a `BadRequest` error is raised.
If an outgoing response fails validation a `InternalServerError` error is
raised.
This middleware can be used in combination with
[`httpErrorHandler`](#httperrorhandler) to automatically return the right
response to the user.
It can also be used in combination with [`httpcontentnegotiation`](#httpContentNegotiation) to load localised translations for the error messages (based on the currently requested language). This feature uses internally [`ajv-i18n`](http://npm.im/ajv-i18n) module, so reference to this module for options and more advanced use cases. By default the language used will be English (`en`), but you can redefine the default language by passing it in the `ajvOptions` options with the key `defaultLanguage` and specifying as value one of the [supported locales](https://www.npmjs.com/package/ajv-i18n#supported-locales).
Also, this middleware accepts an object with plugins to be applied to customize the internal `ajv` instance.
## Install
To install this middleware you can use NPM:
```bash
npm install --save middy-ajv
```
Requires: @middy/core:>=2.0.0
## Options
- `eventSchema` (function) (default `undefined`): The JSON schema compiled ajv validator that will be used
to validate the input (`request.event`) of the Lambda handler.
- `contextSchema` (function) (default `undefined`): The JSON schema object or compiled ajv validator that will be used
to validate the input (`request.context`) of the Lambda handler. Has additional support for `typeof` keyword to allow validation of `"typeof":"function"`.
- `responseSchema` (function) (default `undefined`): The JSON schema compiled ajv validator that will be used
to validate the output (`request.response`) of the Lambda handler.
- `availableLanguages` (object) (optional): Error messages can be returned in multiple languages using [`ajv-i18n`](https://www.npmjs.com/package/ajv-i18n). Language is selected based on `event.preferredLanguage` set by `@middy/http-content-negotiation`. Should be in the format: `{ 'en': require('ajv-i18n/localize/en') }`.
- `defaultLanguage` (string) (default: `en`): The default language to use when `availableLanguages` is provided and `event.preferredLanguage` is not supported.
NOTES:
- At least one of `eventSchema` or `responseSchema` is required.
## Sample usage
Example for validation using precompiled schema:
```javascript
import middy from '@middy/core'
import validator from 'middy-ajv'
const handler = middy((event, context) => {
return {}
})
const eventSchema = require('schema.js')
handler.use(validator({ eventSchema }))
// invokes the handler, note that property foo is missing
const event = {
body: JSON.stringify({something: 'somethingelse'})
}
handler(event, {}, (err, res) => {
t.is(err.message,'Event object failed validation')
})
```
## Build step
### Folder Structure
```shell
{project}
|-- handlers
| |-- {endpoint}
| | |-- index.js
| | |-- schema.event.json
| | |-- schema.context.json
| | |-- schema.response.json
```
### Install
```shell
$ npm install -D ajv-cli
```
### Run
```shell
# or write your own
npx middy-ajv
```
After the compile script has been run on the `endpoint` folder, it will contain `schema.event.js`, `schema.context.js`, `schema.response.js` and `index.js`.
## Middy documentation and examples
For more documentation and examples, refers to the main [Middy monorepo on GitHub](https://github.com/middyjs/middy) or [Middy official website](https://middy.js.org).
## Contributing
Everyone is very welcome to contribute to this repository. Feel free to [raise issues](https://github.com/middyjs/middy/issues) or to [submit Pull Requests](https://github.com/middyjs/middy/pulls).
## License
Licensed under [MIT License](LICENSE). Copyright (c) 2017-2021 will Farrell and the [Middy team](https://github.com/middyjs/middy/graphs/contributors).
