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package events
import (
"context"
"errors"
"slices"
"strings"
"time"
)
const (
CapabilitySubscribe = "events.subscribe"
CapabilityDeliver = "events.deliver"
HandlerKind = "EventHandler"
RecordWatchKind = "AtprotoRecordWatch"
ScopeAll = "*"
)
var ErrFutureCursor = errors.New("events: the cursor is past the source's newest event")
type Op struct {
Action string
Path string
CID string
Prev string
}
type Event struct {
Source string
Seq int64
Repo string
Commit string
Rev string
Time time.Time
Ops []Op
ServerFilter *ServerFilter
}
type ServerFilterSupport string
const (
ServerFilterSupported ServerFilterSupport = "true"
ServerFilterUnsupported ServerFilterSupport = "false"
ServerFilterUnknown ServerFilterSupport = "unknown"
MaxServerFilterCollections = 100
MaxServerFilterDIDs = 10000
WantedCollectionsParam = "wantedCollections"
WantedDIDsParam = "wantedDids"
ServerFilterInfoName = "ServerFilter"
collectionWildcard = ".*"
logDIDs = 10
)
func MatchCollection(patterns []string, collection string) bool {
for _, p := range patterns {
p = strings.TrimSpace(p)
if prefix, ok := strings.CutSuffix(p, collectionWildcard); ok {
if strings.HasPrefix(collection, prefix+".") {
return true
}
continue
}
if p == collection {
return true
}
}
return false
}
type ServerFilter struct {
Collections []string
DIDs []string
Supported ServerFilterSupport
}
func (f *ServerFilter) Gapless() bool {
return f != nil && f.Supported == ServerFilterSupported
}
type Filter struct {
Collections []string
DIDs []string
Cursor *int64
}
type Stream interface {
Next(ctx context.Context) (Event, error)
Close() error
}
type SavedCursor struct {
Cursor int64
SavedAt time.Time
}
type CursorStore interface {
Load(workspace, name, uid string) (SavedCursor, bool)
Save(workspace, name, uid string, cursor int64) error
}
type Source interface {
Subscribe(ctx context.Context, filter Filter) (Stream, error)
}
type Sink interface {
Deliver(ctx context.Context, event Event) error
}
func (f Filter) Scope() []string {
var out []string
for _, v := range append(append([]string(nil), f.Collections...), f.DIDs...) {
if v = strings.TrimSpace(v); v != "" && !slices.Contains(out, v) {
out = append(out, v)
}
}
if len(out) == 0 {
return []string{ScopeAll}
}
return out
}
func (f Filter) ServerParams() (collections, dids []string) {
collections, dids = trimmedUnique(f.Collections), trimmedUnique(f.DIDs)
if len(collections) > MaxServerFilterCollections {
collections = nil
}
if len(dids) > MaxServerFilterDIDs {
dids = nil
}
return collections, dids
}
func LogDIDs(dids []string) []string {
if len(dids) > logDIDs {
return dids[:logDIDs]
}
return dids
}
func trimmedUnique(in []string) []string {
var out []string
seen := map[string]bool{}
for _, v := range in {
if v = strings.TrimSpace(v); v != "" && !seen[v] {
seen[v] = true
out = append(out, v)
}
}
return out
}
func (f Filter) Narrow(e Event) Event {
if len(f.DIDs) > 0 && !slices.ContainsFunc(f.DIDs, func(d string) bool { return strings.TrimSpace(d) == e.Repo }) {
e.Ops = nil
return e
}
if len(f.Collections) == 0 {
return e
}
kept := make([]Op, 0, len(e.Ops))
for _, op := range e.Ops {
collection, _, _ := strings.Cut(op.Path, "/")
if MatchCollection(f.Collections, collection) {
kept = append(kept, op)
}
}
e.Ops = kept
return e
}
