vercel/packages/edge/docs/README.md

@vercel/edge

Table of contents

Interfaces

• ExtraResponseInit
• Geo
• ModifiedRequest

Variables

• CITY_HEADER_NAME
• COUNTRY_HEADER_NAME
• IP_HEADER_NAME
• LATITUDE_HEADER_NAME
• LONGITUDE_HEADER_NAME
• REGION_HEADER_NAME
• REQUEST_ID_HEADER_NAME

Functions

• geolocation
• ipAddress
• json
• next
• rewrite

Variables

CITY_HEADER_NAME

• Const CITY_HEADER_NAME: "x-vercel-ip-city"

City of the original client IP as calculated by Vercel Proxy.

Defined in

packages/edge/src/edge-headers.ts:4

---

COUNTRY_HEADER_NAME

• Const COUNTRY_HEADER_NAME: "x-vercel-ip-country"

Country of the original client IP as calculated by Vercel Proxy.

Defined in

packages/edge/src/edge-headers.ts:8

---

IP_HEADER_NAME

• Const IP_HEADER_NAME: "x-real-ip"

Client IP as calcualted by Vercel Proxy.

Defined in

packages/edge/src/edge-headers.ts:12

---

LATITUDE_HEADER_NAME

• Const LATITUDE_HEADER_NAME: "x-vercel-ip-latitude"

Latitude of the original client IP as calculated by Vercel Proxy.

Defined in

packages/edge/src/edge-headers.ts:16

---

LONGITUDE_HEADER_NAME

• Const LONGITUDE_HEADER_NAME: "x-vercel-ip-longitude"

Longitude of the original client IP as calculated by Vercel Proxy.

Defined in

packages/edge/src/edge-headers.ts:20

---

REGION_HEADER_NAME

• Const REGION_HEADER_NAME: "x-vercel-ip-country-region"

Country region of the original client IP calculated by Vercel Proxy.

See docs.

Defined in

packages/edge/src/edge-headers.ts:26

---

REQUEST_ID_HEADER_NAME

• Const REQUEST_ID_HEADER_NAME: "x-vercel-id"

The request ID for each request generated by Vercel Proxy.

Defined in

packages/edge/src/edge-headers.ts:30

Functions

geolocation

▸ geolocation(request): Geo

Returns the location information for the incoming request.

See

• CITY_HEADER_NAME
• COUNTRY_HEADER_NAME
• REGION_HEADER_NAME
• LATITUDE_HEADER_NAME
• LONGITUDE_HEADER_NAME

Parameters

Name	Type	Description
request	Request	The incoming request object which provides the geolocation data

Returns

Geo

Defined in

packages/edge/src/edge-headers.ts:106

---

ipAddress

▸ ipAddress(request): string | undefined

Returns the IP address of the request from the headers.

See

IP_HEADER_NAME

Parameters

Name	Type	Description
request	Request	The incoming request object which provides the IP

Returns

string | undefined

Defined in

packages/edge/src/edge-headers.ts:77

---

json

▸ json(data, init?): Response

Builds a response object from a serializable JavaScript object:

• sets the 'Content-Type' response header to 'application/json'
• sets the response body from provided data

See

https://fetch.spec.whatwg.org/#dom-response-json

Example

Building a JSON response

import { json } from '@vercel/edge';

const response = json(
  { notification: { success: true, content: 'worked' } },
  { headers: { 'x-custom': '1' } }
);

Parameters

Name	Type	Description
data	any	serialized data
init?	ResponseInit	optional custom response status, statusText and headers

Returns

Response

Defined in

packages/edge/src/response.ts:19

---

next

▸ next(init?): Response

Returns a Response that instructs the system to continue processing the request.

Example

No-op middleware

import { next } from '@vercel/edge';

export default function middleware(_req: Request) {
  return next();
}

Example

Add response headers to all requests

import { next } from '@vercel/edge';

export default function middleware(_req: Request) {
  return next({
    headers: { 'x-from-middleware': 'true' },
  });
}

Parameters

Name	Type	Description
init?	ExtraResponseInit	Additional options for the response

Returns

Response

Defined in

packages/edge/src/middleware-helpers.ts:145

---

rewrite

▸ rewrite(destination, init?): Response

Returns a response that rewrites the request to a different URL.

Example

Rewrite all feature-flagged requests from `/:path*` to `/experimental/:path*`

import { rewrite, next } from '@vercel/edge';

export default async function middleware(req: Request) {
  const flagged = await getFlag(req, 'isExperimental');
  if (flagged) {
    const url = new URL(req.url);
    url.pathname = `/experimental{url.pathname}`;
    return rewrite(url);
  }

  return next();
}

Example

JWT authentication for `/api/:path*` requests

import { rewrite, next } from '@vercel/edge';

export default function middleware(req: Request) {
  const auth = checkJwt(req.headers.get('Authorization'));
  if (!checkJwt) {
    return rewrite(new URL('/api/error-unauthorized', req.url));
  }
  const url = new URL(req.url);
  url.searchParams.set('_userId', auth.userId);
  return rewrite(url);
}

export const config = { matcher: '/api/users/:path*' };

Parameters

Name	Type	Description
destination	string | URL	new URL to rewrite the request to
init?	ExtraResponseInit	Additional options for the response

Returns

Response

Defined in

packages/edge/src/middleware-helpers.ts:101