webpush

README

webpush-go

Web Push API Encryption with VAPID support.

go get -u github.com/SherClockHolmes/webpush-go

Example

For a full example, refer to the code in the example directory.

package main

import (
	"encoding/json"

	webpush "github.com/SherClockHolmes/webpush-go"
)

func main() {
	// Decode subscription
	s := &webpush.Subscription{}
	json.Unmarshal([]byte("<YOUR_SUBSCRIPTION>"), s)

	// Send Notification
	resp, err := webpush.SendNotification([]byte("Test"), s, &webpush.Options{
		Subscriber:      "example@example.com",
		VAPIDPublicKey:  "<YOUR_VAPID_PUBLIC_KEY>",
		VAPIDPrivateKey: "<YOUR_VAPID_PRIVATE_KEY>",
		TTL:             30,
	})
	if err != nil {
		// TODO: Handle error
	}
	defer resp.Body.Close()
}

Auth Scheme

Due to inconsistencies in how different browsers have implemented the Web Push protocol, it is necessary to specify which VAPID authentication scheme to use.

• vapid: The original scheme, used by Firefox and other browsers.
• webpush: The modern scheme, used by Chrome.

You can specify the scheme in the Options struct:

&webpush.Options{
    AuthScheme: webpush.WebPush,
    // ... other options
}

If no AuthScheme is specified, it will default to vapid.

Generating VAPID Keys

Use the helper method GenerateVAPIDKeys to generate the VAPID key pair.

privateKey, publicKey, err := webpush.GenerateVAPIDKeys()
if err != nil {
	// TODO: Handle error
}

Development

1. Install Go 1.11+
2. go mod vendor
3. go test

For other language implementations visit:

WebPush Libs

Documentation

Index

• Constants
• Variables
• func GenerateVAPIDKeys() (privateKey, publicKey string, err error)
• func SendNotification(message []byte, s *Subscription, options *Options) (*http.Response, error)
• func SendNotificationWithContext(ctx context.Context, message []byte, s *Subscription, options *Options) (*http.Response, error)
• type AuthScheme
• type HTTPClient
• type Keys
• type Options
• type Subscription
• type Urgency

Constants

const MaxRecordSize uint32 = 4096

Variables

var ErrMaxPadExceeded = errors.New("payload has exceeded the maximum length")

Functions

func GenerateVAPIDKeys

func GenerateVAPIDKeys() (privateKey, publicKey string, err error)

GenerateVAPIDKeys will create a private and public VAPID key pair

func SendNotification

func SendNotification(message []byte, s *Subscription, options *Options) (*http.Response, error)

SendNotification calls SendNotificationWithContext with default context for backwards-compatibility

func SendNotificationWithContext

func SendNotificationWithContext(ctx context.Context, message []byte, s *Subscription, options *Options) (*http.Response, error)

SendNotificationWithContext sends a push notification to a subscription's endpoint Message Encryption for Web Push, and VAPID protocols. FOR MORE INFORMATION SEE RFC8291: https://datatracker.ietf.org/doc/rfc8291

Types

type AuthScheme

type AuthScheme string

AuthScheme is the type for VAPID authentication schemes.

const (
	// Vapid is the original VAPID scheme.
	Vapid AuthScheme = "vapid"
	// WebPush is the modern VAPID scheme.
	WebPush AuthScheme = "webpush"
)

type HTTPClient

type HTTPClient interface {
	Do(*http.Request) (*http.Response, error)
}

HTTPClient is an interface for sending the notification HTTP request / testing

type Keys

type Keys struct {
	Auth   string `json:"auth"`
	P256dh string `json:"p256dh"`
}

Keys are the base64 encoded values from PushSubscription.getKey()

type Options

type Options struct {
	AuthScheme      AuthScheme // VAPID authentication scheme, defaults to "vapid"
	HTTPClient      HTTPClient // Will replace with *http.Client by default if not included
	RecordSize      uint32     // Limit the record size
	Subscriber      string     // Sub in VAPID JWT token
	Topic           string     // Set the Topic header to collapse a pending messages (Optional)
	TTL             int        // Set the TTL on the endpoint POST request
	Urgency         Urgency    // Set the Urgency header to change a message priority (Optional)
	VAPIDPublicKey  string     // VAPID public key, passed in VAPID Authorization header
	VAPIDPrivateKey string     // VAPID private key, used to sign VAPID JWT token
	VapidExpiration time.Time  // optional expiration for VAPID JWT token (defaults to now + 12 hours)
}

Options are config and extra params needed to send a notification

type Subscription

type Subscription struct {
	Endpoint string `json:"endpoint"`
	Keys     Keys   `json:"keys"`
}

Subscription represents a PushSubscription object from the Push API

type Urgency

type Urgency string

Urgency indicates to the push service how important a message is to the user. This can be used by the push service to help conserve the battery life of a user's device by only waking up for important messages when battery is low.

const (
	// UrgencyVeryLow requires device state: on power and Wi-Fi
	UrgencyVeryLow Urgency = "very-low"
	// UrgencyLow requires device state: on either power or Wi-Fi
	UrgencyLow Urgency = "low"
	// UrgencyNormal excludes device state: low battery
	UrgencyNormal Urgency = "normal"
	// UrgencyHigh admits device state: low battery
	UrgencyHigh Urgency = "high"
)