medusa-store/www/apps/docs/content/references/services/classes/MiddlewareService.mdx

---
displayed_sidebar: servicesSidebar
---

import ParameterTypes from "@site/src/components/ParameterTypes"

# MiddlewareService

Orchestrates dynamic middleware registered through the Medusa Middleware API

## Constructors

#### constructor

`**new MiddlewareService**()`

## Properties

<ParameterTypes parameters={[
  {
    "name": "postAuthentication_",
    "type": "[middlewareType](../types/middlewareType.mdx)[]",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  },
  {
    "name": "preAuthentication_",
    "type": "[middlewareType](../types/middlewareType.mdx)[]",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  },
  {
    "name": "preCartCreation_",
    "type": "RequestHandler&#60;ParamsDictionary, any, any, ParsedQs, Record&#60;string, any&#62;&#62;[]",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  },
  {
    "name": "routers",
    "type": "`Record<string, Router[]>`",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

## Methods

#### addPostAuthentication

`**addPostAuthentication**(middleware, options): void`

Adds a middleware function to be called after authentication is completed.

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "middleware",
    "type": "[middlewareHandlerType](../types/middlewareHandlerType.mdx)",
    "description": "the middleware function. Should return a middleware function.",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  },
  {
    "name": "options",
    "type": "`Record<string, unknown>`",
    "description": "the arguments that will be passed to the middleware",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "void",
    "expandable": false,
    "children": []
  }
]} />

___

#### addPreAuthentication

`**addPreAuthentication**(middleware, options): void`

Adds a middleware function to be called before authentication is completed.

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "middleware",
    "type": "[middlewareHandlerType](../types/middlewareHandlerType.mdx)",
    "description": "the middleware function. Should return a middleware function.",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  },
  {
    "name": "options",
    "type": "`Record<string, unknown>`",
    "description": "the arguments that will be passed to the middleware",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "void",
    "expandable": false,
    "children": []
  }
]} />

___

#### addPreCartCreation

`**addPreCartCreation**(middleware): void`

Adds a middleware function to be called before cart creation

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "middleware",
    "type": "RequestHandler&#60;ParamsDictionary, any, any, ParsedQs, Record&#60;string, any&#62;&#62;",
    "description": "the middleware function. Should return a middleware function.",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "",
    "expandable": false,
    "children": []
  }
]} />

___

#### addRouter

`**addRouter**(path, router): void`

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "path",
    "type": "`string`",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  },
  {
    "name": "router",
    "type": "Router",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "",
    "expandable": false,
    "children": []
  }
]} />

___

#### getRouters

`**getRouters**(path): Router[]`

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "path",
    "type": "`string`",
    "description": "",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

Router[]

<ParameterTypes parameters={[
  {
    "name": "Router[]",
    "type": "Router[]",
    "optional": false,
    "defaultValue": "",
    "description": "",
    "expandable": false,
    "children": []
  }
]} />

___

#### usePostAuthentication

`**usePostAuthentication**(app): void`

Adds post authentication middleware to an express app.

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "app",
    "type": "Router",
    "description": "the express app to add the middleware to",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "",
    "expandable": false,
    "children": []
  }
]} />

___

#### usePreAuthentication

`**usePreAuthentication**(app): void`

Adds pre authentication middleware to an express app.

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "app",
    "type": "Router",
    "description": "the express app to add the middleware to",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "",
    "expandable": false,
    "children": []
  }
]} />

___

#### usePreCartCreation

`**usePreCartCreation**(): RequestHandler&#60;ParamsDictionary, any, any, ParsedQs, Record&#60;string, any&#62;&#62;[]`

##### Returns

RequestHandler&#60;ParamsDictionary, any, any, ParsedQs, Record&#60;string, any&#62;&#62;[]

<ParameterTypes parameters={[
  {
    "name": "RequestHandler&#60;ParamsDictionary, any, any, ParsedQs, Record&#60;string, any&#62;&#62;[]",
    "type": "RequestHandler&#60;ParamsDictionary, any, any, ParsedQs, Record&#60;string, any&#62;&#62;[]",
    "optional": false,
    "defaultValue": "",
    "description": "",
    "expandable": false,
    "children": []
  }
]} />

___

#### validateMiddleware\_

`**validateMiddleware_**(fn): void`

Validates a middleware function, throws if fn is not of type function.

##### Parameters

<ParameterTypes parameters={[
  {
    "name": "fn",
    "type": "`unknown`",
    "description": "the middleware function to validate.",
    "optional": false,
    "defaultValue": "",
    "expandable": false,
    "children": []
  }
]} />

##### Returns

`void`

<ParameterTypes parameters={[
  {
    "name": "void",
    "type": "`void`",
    "optional": true,
    "defaultValue": "",
    "description": "nothing if the middleware is a function",
    "expandable": false,
    "children": []
  }
]} />