feat(coderd): add webpush package (#17091)

* Adds `codersdk.ExperimentWebPush` (`web-push`)
* Adds a `coderd/webpush` package that allows sending native push
notifications via `github.com/SherClockHolmes/webpush-go`
* Adds database tables to store push notification subscriptions.
* Adds an API endpoint that allows users to subscribe/unsubscribe, and
send a test notification (404 without experiment, excluded from API docs)
* Adds server CLI command to regenerate VAPID keys (note: regenerating
the VAPID keypair requires deleting all existing subscriptions)

---------

Co-authored-by: Kyle Carberry <kyle@carberry.com>

coderd/webpush.go

@@ -0,0 +1,160 @@
+package coderd
+
+import (
+	"database/sql"
+	"errors"
+	"net/http"
+	"slices"
+
+	"github.com/coder/coder/v2/coderd/database"
+	"github.com/coder/coder/v2/coderd/database/dbtime"
+	"github.com/coder/coder/v2/coderd/httpapi"
+	"github.com/coder/coder/v2/coderd/httpmw"
+	"github.com/coder/coder/v2/coderd/rbac"
+	"github.com/coder/coder/v2/coderd/rbac/policy"
+	"github.com/coder/coder/v2/codersdk"
+)
+
+// @Summary Create user webpush subscription
+// @ID create-user-webpush-subscription
+// @Security CoderSessionToken
+// @Accept json
+// @Tags Notifications
+// @Param request body codersdk.WebpushSubscription true "Webpush subscription"
+// @Param user path string true "User ID, name, or me"
+// @Router /users/{user}/webpush/subscription [post]
+// @Success 204
+// @x-apidocgen {"skip": true}
+func (api *API) postUserWebpushSubscription(rw http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	user := httpmw.UserParam(r)
+	if !api.Experiments.Enabled(codersdk.ExperimentWebPush) {
+		httpapi.ResourceNotFound(rw)
+		return
+	}
+
+	var req codersdk.WebpushSubscription
+	if !httpapi.Read(ctx, rw, r, &req) {
+		return
+	}
+
+	if err := api.WebpushDispatcher.Test(ctx, req); err != nil {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to test webpush subscription",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
+	if _, err := api.Database.InsertWebpushSubscription(ctx, database.InsertWebpushSubscriptionParams{
+		CreatedAt:         dbtime.Now(),
+		UserID:            user.ID,
+		Endpoint:          req.Endpoint,
+		EndpointAuthKey:   req.AuthKey,
+		EndpointP256dhKey: req.P256DHKey,
+	}); err != nil {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to insert push notification subscription.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
+	rw.WriteHeader(http.StatusNoContent)
+}
+
+// @Summary Delete user webpush subscription
+// @ID delete-user-webpush-subscription
+// @Security CoderSessionToken
+// @Accept json
+// @Tags Notifications
+// @Param request body codersdk.DeleteWebpushSubscription true "Webpush subscription"
+// @Param user path string true "User ID, name, or me"
+// @Router /users/{user}/webpush/subscription [delete]
+// @Success 204
+// @x-apidocgen {"skip": true}
+func (api *API) deleteUserWebpushSubscription(rw http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	user := httpmw.UserParam(r)
+
+	if !api.Experiments.Enabled(codersdk.ExperimentWebPush) {
+		httpapi.ResourceNotFound(rw)
+		return
+	}
+
+	var req codersdk.DeleteWebpushSubscription
+	if !httpapi.Read(ctx, rw, r, &req) {
+		return
+	}
+
+	// Return NotFound if the subscription does not exist.
+	if existing, err := api.Database.GetWebpushSubscriptionsByUserID(ctx, user.ID); err != nil && errors.Is(err, sql.ErrNoRows) {
+		httpapi.Write(ctx, rw, http.StatusNotFound, codersdk.Response{
+			Message: "Webpush subscription not found.",
+		})
+		return
+	} else if idx := slices.IndexFunc(existing, func(s database.WebpushSubscription) bool {
+		return s.Endpoint == req.Endpoint
+	}); idx == -1 {
+		httpapi.Write(ctx, rw, http.StatusNotFound, codersdk.Response{
+			Message: "Webpush subscription not found.",
+		})
+		return
+	}
+
+	if err := api.Database.DeleteWebpushSubscriptionByUserIDAndEndpoint(ctx, database.DeleteWebpushSubscriptionByUserIDAndEndpointParams{
+		UserID:   user.ID,
+		Endpoint: req.Endpoint,
+	}); err != nil {
+		if errors.Is(err, sql.ErrNoRows) {
+			httpapi.Write(ctx, rw, http.StatusNotFound, codersdk.Response{
+				Message: "Webpush subscription not found.",
+			})
+			return
+		}
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to delete push notification subscription.",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
+	rw.WriteHeader(http.StatusNoContent)
+}
+
+// @Summary Send a test push notification
+// @ID send-a-test-push-notification
+// @Security CoderSessionToken
+// @Tags Notifications
+// @Param user path string true "User ID, name, or me"
+// @Success 204
+// @Router /users/{user}/webpush/test [post]
+// @x-apidocgen {"skip": true}
+func (api *API) postUserPushNotificationTest(rw http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	user := httpmw.UserParam(r)
+
+	if !api.Experiments.Enabled(codersdk.ExperimentWebPush) {
+		httpapi.ResourceNotFound(rw)
+		return
+	}
+
+	// We need to authorize the user to send a push notification to themselves.
+	if !api.Authorize(r, policy.ActionCreate, rbac.ResourceNotificationMessage.WithOwner(user.ID.String())) {
+		httpapi.Forbidden(rw)
+		return
+	}
+
+	if err := api.WebpushDispatcher.Dispatch(ctx, user.ID, codersdk.WebpushMessage{
+		Title: "It's working!",
+		Body:  "You've subscribed to push notifications.",
+	}); err != nil {
+		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
+			Message: "Failed to send test notification",
+			Detail:  err.Error(),
+		})
+		return
+	}
+
+	rw.WriteHeader(http.StatusNoContent)
+}