s/backend/middleware

middleware/middleware.go

@@ -0,0 +1,109 @@
+// Package middleware implements the TrackerLogic interface by executing
+// a series of middleware hooks.
+package middleware
+
+import (
+	"log"
+	"time"
+
+	"golang.org/x/net/context"
+
+	"github.com/jzelinskie/trakr/bittorrent"
+	"github.com/jzelinskie/trakr/frontend"
+)
+
+type Config struct {
+	AnnounceInterval time.Duration `yaml:"announce_interval"`
+}
+
+var _ frontend.TrackerLogic = &Logic{}
+
+func NewLogic(config Config, peerStore PeerStore, announcePreHooks, announcePostHooks, scrapePreHooks, scrapePostHooks []Hook) *Logic {
+	l := &Logic{
+		announceInterval:  config.AnnounceInterval,
+		peerStore:         peerStore,
+		announcePreHooks:  announcePreHooks,
+		announcePostHooks: announcePostHooks,
+		scrapePreHooks:    scrapePreHooks,
+		scrapePostHooks:   scrapePostHooks,
+	}
+
+	if len(l.announcePreHooks) == 0 {
+		l.announcePreHooks = []Hook{nopHook{}}
+	}
+
+	if len(l.announcePostHooks) == 0 {
+		l.announcePostHooks = []Hook{nopHook{}}
+	}
+
+	if len(l.scrapePreHooks) == 0 {
+		l.scrapePreHooks = []Hook{nopHook{}}
+	}
+
+	if len(l.scrapePostHooks) == 0 {
+		l.scrapePostHooks = []Hook{nopHook{}}
+	}
+
+	return l
+}
+
+// Logic is an implementation of the TrackerLogic that functions by
+// executing a series of middleware hooks.
+type Logic struct {
+	announceInterval  time.Duration
+	peerStore         PeerStore
+	announcePreHooks  []Hook
+	announcePostHooks []Hook
+	scrapePreHooks    []Hook
+	scrapePostHooks   []Hook
+}
+
+// HandleAnnounce generates a response for an Announce.
+func (l *Logic) HandleAnnounce(ctx context.Context, req *bittorrent.AnnounceRequest) (*bittorrent.AnnounceResponse, error) {
+	resp := &bittorrent.AnnounceResponse{
+		Interval: l.announceInterval,
+	}
+	for _, h := range l.announcePreHooks {
+		if err := h.HandleAnnounce(ctx, req, resp); err != nil {
+			return nil, err
+		}
+	}
+
+	return resp, nil
+}
+
+// AfterAnnounce does something with the results of an Announce after it has
+// been completed.
+func (l *Logic) AfterAnnounce(ctx context.Context, req *bittorrent.AnnounceRequest, resp *bittorrent.AnnounceResponse) {
+	for _, h := range l.announcePostHooks {
+		if err := h.HandleAnnounce(ctx, req, resp); err != nil {
+			log.Println("trakr: post-announce hooks failed:", err.Error())
+			return
+		}
+	}
+}
+
+// HandleScrape generates a response for a Scrape.
+func (l *Logic) HandleScrape(ctx context.Context, req *bittorrent.ScrapeRequest) (*bittorrent.ScrapeResponse, error) {
+	resp := &bittorrent.ScrapeResponse{
+		Files: make(map[bittorrent.InfoHash]bittorrent.Scrape),
+	}
+	for _, h := range l.scrapePreHooks {
+		if err := h.HandleScrape(ctx, req, resp); err != nil {
+			return nil, err
+		}
+	}
+
+	return resp, nil
+}
+
+// AfterScrape does something with the results of a Scrape after it has been
+// completed.
+func (l *Logic) AfterScrape(ctx context.Context, req *bittorrent.ScrapeRequest, resp *bittorrent.ScrapeResponse) {
+	for _, h := range l.scrapePostHooks {
+		if err := h.HandleScrape(ctx, req, resp); err != nil {
+			log.Println("trakr: post-scrape hooks failed:", err.Error())
+			return
+		}
+	}
+}