Add stub RSS Service. Add DefaultService. Add Poller interface.

`DefaultService` serves as a useful no-op service to cut down on bloat when
implementing new Services. This means we can add more methods more freely to
the interface of `Service` without bogging down the Service implementation.

`Poller` is an interface which contains a polling interval and a function to
invoke. This will be used for RSS feeds.

Implemented a stub `RSSService`.

src/github.com/matrix-org/go-neb/database/db.go

@@ -125,6 +125,19 @@ func (d *ServiceDB) LoadServicesForUser(serviceUserID string) (services []types.
 	return
 }
 
+// LoadServicesByType loads all the bot services configured for a given type.
+// Returns an empty list if there aren't any services configured.
+func (d *ServiceDB) LoadServicesByType(serviceType string) (services []types.Service, err error) {
+	err = runTransaction(d.db, func(txn *sql.Tx) error {
+		services, err = selectServicesByTypeTxn(txn, serviceType)
+		if err != nil {
+			return err
+		}
+		return nil
+	})
+	return
+}
+
 // StoreService stores a service into the database either by inserting a new
 // service or updating an existing service. Returns the old service if there
 // was one.

src/github.com/matrix-org/go-neb/database/schema.go

@@ -231,6 +231,33 @@ func selectServicesForUserTxn(txn *sql.Tx, userID string) (srvs []types.Service,
 	return
 }
 
+const selectServicesByTypeSQL = `
+SELECT service_id, service_user_id, service_json FROM services WHERE service_type=$1 ORDER BY service_id
+`
+
+func selectServicesByTypeTxn(txn *sql.Tx, serviceType string) (srvs []types.Service, err error) {
+	rows, err := txn.Query(selectServicesByTypeSQL, serviceType)
+	if err != nil {
+		return
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var s types.Service
+		var serviceID string
+		var serviceUserID string
+		var serviceJSON []byte
+		if err = rows.Scan(&serviceID, &serviceUserID, &serviceJSON); err != nil {
+			return
+		}
+		s, err = types.CreateService(serviceID, serviceType, serviceUserID, serviceJSON)
+		if err != nil {
+			return
+		}
+		srvs = append(srvs, s)
+	}
+	return
+}
+
 const deleteServiceSQL = `
 DELETE FROM services WHERE service_id = $1
 `

src/github.com/matrix-org/go-neb/services/echo/echo.go

@@ -4,20 +4,18 @@ import (
 	"github.com/matrix-org/go-neb/matrix"
 	"github.com/matrix-org/go-neb/plugin"
 	"github.com/matrix-org/go-neb/types"
-	"net/http"
 	"strings"
 )
 
 type echoService struct {
+	types.DefaultService
 	id            string
 	serviceUserID string
 }
 
-func (e *echoService) ServiceUserID() string                                          { return e.serviceUserID }
-func (e *echoService) ServiceID() string                                              { return e.id }
-func (e *echoService) ServiceType() string                                            { return "echo" }
-func (e *echoService) Register(oldService types.Service, client *matrix.Client) error { return nil }
-func (e *echoService) PostRegister(oldService types.Service)                          {}
+func (e *echoService) ServiceUserID() string { return e.serviceUserID }
+func (e *echoService) ServiceID() string     { return e.id }
+func (e *echoService) ServiceType() string   { return "echo" }
 func (e *echoService) Plugin(cli *matrix.Client, roomID string) plugin.Plugin {
 	return plugin.Plugin{
 		Commands: []plugin.Command{
@@ -30,9 +28,6 @@ func (e *echoService) Plugin(cli *matrix.Client, roomID string) plugin.Plugin {
 		},
 	}
 }
-func (e *echoService) OnReceiveWebhook(w http.ResponseWriter, req *http.Request, cli *matrix.Client) {
-	w.WriteHeader(200) // Do nothing
-}
 
 func init() {
 	types.RegisterService(func(serviceID, serviceUserID, webhookEndpointURL string) types.Service {

src/github.com/matrix-org/go-neb/services/giphy/giphy.go

@@ -31,6 +31,7 @@ type giphySearch struct {
 }
 
 type giphyService struct {
+	types.DefaultService
 	id            string
 	serviceUserID string
 	APIKey        string // beta key is dc6zaTOxFJmzC
@@ -39,10 +40,6 @@ type giphyService struct {
 func (s *giphyService) ServiceUserID() string { return s.serviceUserID }
 func (s *giphyService) ServiceID() string     { return s.id }
 func (s *giphyService) ServiceType() string   { return "giphy" }
-func (s *giphyService) OnReceiveWebhook(w http.ResponseWriter, req *http.Request, cli *matrix.Client) {
-}
-func (s *giphyService) Register(oldService types.Service, client *matrix.Client) error { return nil }
-func (s *giphyService) PostRegister(oldService types.Service)                          {}
 
 func (s *giphyService) Plugin(client *matrix.Client, roomID string) plugin.Plugin {
 	return plugin.Plugin{

src/github.com/matrix-org/go-neb/services/github/github.go

@@ -11,7 +11,6 @@ import (
 	"github.com/matrix-org/go-neb/realms/github"
 	"github.com/matrix-org/go-neb/services/github/client"
 	"github.com/matrix-org/go-neb/types"
-	"net/http"
 	"regexp"
 	"strconv"
 	"strings"
@@ -23,6 +22,7 @@ var ownerRepoIssueRegex = regexp.MustCompile(`(([A-z0-9-_]+)/([A-z0-9-_]+))?#([0
 var ownerRepoRegex = regexp.MustCompile(`^([A-z0-9-_]+)/([A-z0-9-_]+)$`)
 
 type githubService struct {
+	types.DefaultService
 	id            string
 	serviceUserID string
 	RealmID       string
@@ -180,9 +180,6 @@ func (s *githubService) Plugin(cli *matrix.Client, roomID string) plugin.Plugin
 		},
 	}
 }
-func (s *githubService) OnReceiveWebhook(w http.ResponseWriter, req *http.Request, cli *matrix.Client) {
-	w.WriteHeader(400)
-}
 
 // Register will create webhooks for the repos specified in Rooms
 //
@@ -212,8 +209,6 @@ func (s *githubService) Register(oldService types.Service, client *matrix.Client
 	return nil
 }
 
-func (s *githubService) PostRegister(oldService types.Service) {}
-
 // defaultRepo returns the default repo for the given room, or an empty string.
 func (s *githubService) defaultRepo(roomID string) string {
 	logger := log.WithFields(log.Fields{

src/github.com/matrix-org/go-neb/services/github/github_webhook.go

@@ -6,7 +6,6 @@ import (
 	"github.com/google/go-github/github"
 	"github.com/matrix-org/go-neb/database"
 	"github.com/matrix-org/go-neb/matrix"
-	"github.com/matrix-org/go-neb/plugin"
 	"github.com/matrix-org/go-neb/services/github/client"
 	"github.com/matrix-org/go-neb/services/github/webhook"
 	"github.com/matrix-org/go-neb/types"
@@ -17,10 +16,11 @@ import (
 )
 
 type githubWebhookService struct {
+	types.DefaultService
 	id                 string
 	serviceUserID      string
 	webhookEndpointURL string
-	ClientUserID       string // optional; required for webhooks
+	ClientUserID       string
 	RealmID            string
 	SecretToken        string
 	Rooms              map[string]struct { // room_id => {}
@@ -33,9 +33,6 @@ type githubWebhookService struct {
 func (s *githubWebhookService) ServiceUserID() string { return s.serviceUserID }
 func (s *githubWebhookService) ServiceID() string     { return s.id }
 func (s *githubWebhookService) ServiceType() string   { return "github-webhook" }
-func (s *githubWebhookService) Plugin(cli *matrix.Client, roomID string) plugin.Plugin {
-	return plugin.Plugin{}
-}
 func (s *githubWebhookService) OnReceiveWebhook(w http.ResponseWriter, req *http.Request, cli *matrix.Client) {
 	evType, repo, msg, err := webhook.OnReceiveRequest(req, s.SecretToken)
 	if err != nil {

src/github.com/matrix-org/go-neb/services/jira/jira.go

@@ -24,6 +24,7 @@ var issueKeyRegex = regexp.MustCompile("([A-z]+)-([0-9]+)")
 var projectKeyRegex = regexp.MustCompile("^[A-z]+$")
 
 type jiraService struct {
+	types.DefaultService
 	id                 string
 	serviceUserID      string
 	webhookEndpointURL string
@@ -38,10 +39,9 @@ type jiraService struct {
 	}
 }
 
-func (s *jiraService) ServiceUserID() string                 { return s.serviceUserID }
-func (s *jiraService) ServiceID() string                     { return s.id }
-func (s *jiraService) ServiceType() string                   { return "jira" }
-func (s *jiraService) PostRegister(oldService types.Service) {}
+func (s *jiraService) ServiceUserID() string { return s.serviceUserID }
+func (s *jiraService) ServiceID() string     { return s.id }
+func (s *jiraService) ServiceType() string   { return "jira" }
 func (s *jiraService) Register(oldService types.Service, client *matrix.Client) error {
 	// We only ever make 1 JIRA webhook which listens for all projects and then filter
 	// on receive. So we simply need to know if we need to make a webhook or not. We

src/github.com/matrix-org/go-neb/services/rss/rss.go

@@ -0,0 +1,35 @@
+package services
+
+import (
+	"github.com/matrix-org/go-neb/matrix"
+	"github.com/matrix-org/go-neb/types"
+)
+
+type rssService struct {
+	types.DefaultService
+	id            string
+	serviceUserID string
+	ClientUserID  string              `json:"client_user_id"`
+	Rooms         map[string]struct { // room_id => {}
+		Feeds map[string]struct { // URL => { }
+			PollIntervalMs int `json:"poll_interval_ms"`
+		} `json:"feeds"`
+	} `json:"rooms"`
+}
+
+func (s *rssService) ServiceUserID() string { return s.serviceUserID }
+func (s *rssService) ServiceID() string     { return s.id }
+func (s *rssService) ServiceType() string   { return "rss" }
+
+// Register will check the liveness of each RSS feed given. If all feeds check out okay, no error is returned.
+func (s *rssService) Register(oldService types.Service, client *matrix.Client) error { return nil }
+
+func init() {
+	types.RegisterService(func(serviceID, serviceUserID, webhookEndpointURL string) types.Service {
+		r := &rssService{
+			id:            serviceID,
+			serviceUserID: serviceUserID,
+		}
+		return r
+	})
+}

src/github.com/matrix-org/go-neb/types/types.go

@@ -40,6 +40,12 @@ type BotOptions struct {
 	Options     map[string]interface{}
 }
 
+// Poller represents a thing that can be polled at a given rate.
+type Poller interface {
+	IntervalSecs() int
+	OnPoll()
+}
+
 // A Service is the configuration for a bot service.
 type Service interface {
 	ServiceUserID() string
@@ -57,6 +63,32 @@ type Service interface {
 	// concurrent modifications to this service whilst this function executes. This lifecycle hook should be used to clean
 	// up resources which are no longer needed (e.g. removing old webhooks).
 	PostRegister(oldService Service)
+	// Return a Poller object if you wish to be invoked every N seconds.
+	Poller() Poller
+}
+
+// DefaultService NO-OPs the implementation of optional Service interface methods. Feel free to override them.
+type DefaultService struct {
+	Service
+}
+
+// Plugin returns no plugins.
+func (s *DefaultService) Plugin(cli *matrix.Client, roomID string) plugin.Plugin {
+	return plugin.Plugin{}
+}
+
+// Register does nothing and returns no error.
+func (s *DefaultService) Register(oldService Service, client *matrix.Client) error { return nil }
+
+// PostRegister does nothing.
+func (s *DefaultService) PostRegister(oldService Service) {}
+
+// Poller returns no poller.
+func (s *DefaultService) Poller() Poller { return nil }
+
+// OnReceiveWebhook does nothing but 200 OK the request.
+func (s *DefaultService) OnReceiveWebhook(w http.ResponseWriter, req *http.Request, cli *matrix.Client) {
+	w.WriteHeader(200) // Do nothing
 }
 
 var baseURL = ""