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https://github.com/entecloud/express-harness
An express.js middleware to validate request before processing
https://github.com/entecloud/express-harness
expressjs lightweight middleware no-dependencies request-middleware typescript validation validator
Last synced: 10 days ago
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An express.js middleware to validate request before processing
- Host: GitHub
- URL: https://github.com/entecloud/express-harness
- Owner: entecloud
- License: mit
- Created: 2020-11-29T18:35:18.000Z (about 4 years ago)
- Default Branch: master
- Last Pushed: 2021-01-03T12:22:54.000Z (about 4 years ago)
- Last Synced: 2024-12-15T14:12:21.050Z (about 2 months ago)
- Topics: expressjs, lightweight, middleware, no-dependencies, request-middleware, typescript, validation, validator
- Language: TypeScript
- Homepage:
- Size: 110 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# express-harness
A fully typed, light-weight, unopinionated and no-dependencies Express.JS middleware that helps with the validation of requests.
In general, as a developer,
- You provide a validation schema that has the following attributes:
- Where to look (_query, body etc.._)
- What to look (_field names_)
- Whether it's required or not
- Defines your own validation logic against this field.
- This middleware will then validate the request with the schema, and if it fails, it'll return the request with `400` (_by default_).
# Installation
```bash
npm i @wunderland/express-harness
```
or
```bash
yarn add @wunderland/express-harness
```
# Examples
## Basic Example
```javascript
import { validateRequest } from "@wunderland/express-harness";
import express from "express";
const app = express();
app.post(
"/",
validateRequest({ body: { user_id: { required: true } } }),
(request, response) => {
return response.status(200).json({ user_id: request.body.user_id });
}
);
```
> Response
```json
{
"error": "Validation for the following fields are failed",
"fields": {
"body": {
"user_id": "user_id is required"
}
}
}
```
## Custom Validation
```javascript
import { validateRequest } from "@wunderland/express-harness";
import express from "express";
const app = express();
app.post(
"/",
validateRequest({
body: {
user_id: {
required: true,
},
age: {
required: false,
validator: (request) => {
const {
body: { age = 5 },
} = request;
if (Number(age) < 10) {
return `You must be at least 10 years old`;
}
return undefined;
},
},
},
}),
(request, response) => {
return response.status(200).json({ user_id: request.body.user_id });
}
);
```
> Response
```json
{
"error": "Validation for the following fields are failed",
"fields": {
"body": {
"age": "You must be at least 10 years old",
"user_id": "user_id is required"
}
}
}
```
# API
`express-harness` exports a named function:
## `validateRequest(schema, [options])`
This `validateRequest` method will validate the express `request` against the specified `schema` and will return a `400` with a default error message (which is configurable through `options`).
### `schema`
The schema is a normal `Object` that has the following type definition:
#### Validation Schema Type
```typescript
type ValidateRequestSchema = {
body?: {
[key: string]: {
required: boolean;
validator?: ValidatorFunction;
};
};
query?: {
[key: string]: {
required: boolean;
validator?: ValidatorFunction;
};
};
files?: {
[key: string]: {
required: boolean;
};
};
params?: {
[key: string]: {
required: boolean;
validator?: ValidatorFunction;
};
};
};
```
### Custom Validation ( `ValidatorFunction` )
You can specify your own validation logic against the fields using this `validator` method.
When specified, this will be invoked with the following argument signature:
```typescript
type ValidatorFunction = (request: Request) => string | undefined;
```
If this validator function returns a string, it'll be treated as an error, and the returned string will be used as the error message. If it's `undefined`, then it'll be considered as no-error.
### `options` `[object]`
Through options, you can configure the _HTTP Error Code_ and format the error response according to your needs. It also does the cleaning of saved files (through `Multer`) in case any of the validation fails (_fail fast_)
```typescript
type ValidateRequestOptions = {
errorCode: number;
formatErrorPayload: (fields: Fields) => any;
cleanupMulter: boolean;
};
```
#### `cleanupMulter`: `[boolean]` (_defaults to `true`_)
Delete the saved files (by `multer`) in case any validation fails.
#### `errorCode` `[number]` (_defaults to `400`_)
The HTTP status code to return on error. You can set any number (although 400 is the preferred).
#### `formatErrorPayload` `[function]` (_defaults to a built-in formatter_)
This is a helper function that'll let you to customize the error response before sending it to the client.
When provided, this function will get invoked with an `object` as its param which has the following signature:
```typescript
type Fields = {
body: { [key: string]: string | undefined };
query: { [key: string]: string | undefined };
params: { [key: string]: string | undefined };
files: { [key: string]: string | undefined };
};
```
# Contribution
There's a pretty high-chance where we might've missed many issues. If you find one, please feel free to fork and submit a patch
# License
This library is licensed under MIT