Replace publicroomsapi with a combination of clientapi/roomserver/currentstateserver (#1174)

* Use content_value instead of membership

* Fix build

* Replace publicroomsapi with a combination of clientapi/roomserver/currentstateserver

- All public rooms paths are now handled by clientapi
- Requests to (un)publish rooms are sent to the roomserver via `PerformPublish`
  which are stored in a new `published_table.go`
- Requests for public rooms are handled in clientapi by:
    * Fetch all room IDs which are published using `QueryPublishedRooms` on the roomserver.
    * Apply pagination parameters to the slice.
    * Do a `QueryBulkStateContent` request to the currentstateserver to pull out
      required state event *content* (not entire events).
    * Aggregate and return the chunk.

Mostly but not fully implemented (DB queries on currentstateserver are missing)

* Fix pq query

* Make postgres work

* Make sqlite work

* Fix tests

* Unbreak pagination tests

* Linting

currentstateserver/storage/tables/interface.go

@@ -19,26 +19,61 @@ import (
 	"database/sql"
 
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/tidwall/gjson"
 )
 
-var MembershipToEnum = map[string]int{
-	gomatrixserverlib.Invite: 1,
-	gomatrixserverlib.Join:   2,
-	gomatrixserverlib.Leave:  3,
-	gomatrixserverlib.Ban:    4,
-}
-var EnumToMembership = map[int]string{
-	1: gomatrixserverlib.Invite,
-	2: gomatrixserverlib.Join,
-	3: gomatrixserverlib.Leave,
-	4: gomatrixserverlib.Ban,
-}
-
 type CurrentRoomState interface {
 	SelectStateEvent(ctx context.Context, roomID, evType, stateKey string) (*gomatrixserverlib.HeaderedEvent, error)
 	SelectEventsWithEventIDs(ctx context.Context, txn *sql.Tx, eventIDs []string) ([]gomatrixserverlib.HeaderedEvent, error)
-	UpsertRoomState(ctx context.Context, txn *sql.Tx, event gomatrixserverlib.HeaderedEvent, membershipEnum int) error
+	// UpsertRoomState stores the given event in the database, along with an extracted piece of content.
+	// The piece of content will vary depending on the event type, and table implementations may use this information to optimise
+	// lookups e.g membership lookups. The mapped value of `contentVal` is outlined in ExtractContentValue. An empty `contentVal`
+	// means there is nothing to store for this field.
+	UpsertRoomState(ctx context.Context, txn *sql.Tx, event gomatrixserverlib.HeaderedEvent, contentVal string) error
 	DeleteRoomStateByEventID(ctx context.Context, txn *sql.Tx, eventID string) error
 	// SelectRoomIDsWithMembership returns the list of room IDs which have the given user in the given membership state.
-	SelectRoomIDsWithMembership(ctx context.Context, txn *sql.Tx, userID string, membershipEnum int) ([]string, error)
+	SelectRoomIDsWithMembership(ctx context.Context, txn *sql.Tx, userID string, membership string) ([]string, error)
+	SelectBulkStateContent(ctx context.Context, roomIDs []string, tuples []gomatrixserverlib.StateKeyTuple, allowWildcards bool) ([]StrippedEvent, error)
+}
+
+// StrippedEvent represents a stripped event for returning extracted content values.
+type StrippedEvent struct {
+	RoomID       string
+	EventType    string
+	StateKey     string
+	ContentValue string
+}
+
+// ExtractContentValue from the given state event. For example, given an m.room.name event with:
+//    content: { name: "Foo" }
+// this returns "Foo".
+func ExtractContentValue(ev *gomatrixserverlib.HeaderedEvent) string {
+	content := ev.Content()
+	key := ""
+	switch ev.Type() {
+	case gomatrixserverlib.MRoomCreate:
+		key = "creator"
+	case gomatrixserverlib.MRoomCanonicalAlias:
+		key = "alias"
+	case gomatrixserverlib.MRoomHistoryVisibility:
+		key = "history_visibility"
+	case gomatrixserverlib.MRoomJoinRules:
+		key = "join_rule"
+	case gomatrixserverlib.MRoomMember:
+		key = "membership"
+	case gomatrixserverlib.MRoomName:
+		key = "name"
+	case "m.room.avatar":
+		key = "url"
+	case "m.room.topic":
+		key = "topic"
+	case "m.room.guest_access":
+		key = "guest_access"
+	}
+	result := gjson.GetBytes(content, key)
+	if !result.Exists() {
+		return ""
+	}
+	// this returns the empty string if this is not a string type
+	return result.Str
 }