announce.go; fmt nitpicks

server/announce.go

@@ -0,0 +1,111 @@
+// Copyright 2013 The Chihaya Authors. All rights reserved.
+// Use of this source code is governed by the BSD 2-Clause license,
+// which can be found in the LICENSE file.
+
+package server
+
+import (
+	"errors"
+	"net/http"
+	"path"
+	"strconv"
+
+	"github.com/chihaya/chihaya/config"
+)
+
+// announce represents all of the data from an announce request.
+type announce struct {
+	Compact    bool
+	Downloaded uint64
+	Event      string
+	IP         string
+	Infohash   string
+	Left       uint64
+	NumWant    int
+	Passkey    string
+	PeerID     string
+	Port       uint64
+	Uploaded   uint64
+}
+
+// newAnnounce parses an HTTP request and generates an Announce.
+func newAnnounce(r *http.Request, conf *config.Config) (*announce, error) {
+	pq, err := parseQuery(r.URL.RawQuery)
+	if err != nil {
+		return nil, err
+	}
+
+	compact := pq.Params["compact"] == "1"
+	downloaded, downloadedErr := pq.getUint64("downloaded")
+	event, _ := pq.Params["event"]
+	infohash, _ := pq.Params["info_hash"]
+	ip, _ := requestedIP(r, pq)
+	left, leftErr := pq.getUint64("left")
+	numWant := requestedPeerCount(conf.DefaultNumWant, pq)
+	passkey, _ := path.Split(r.URL.Path)
+	peerID, _ := pq.Params["peer_id"]
+	port, portErr := pq.getUint64("port")
+	uploaded, uploadedErr := pq.getUint64("uploaded")
+
+	if downloadedErr != nil ||
+		infohash == "" ||
+		leftErr != nil ||
+		peerID == "" ||
+		portErr != nil ||
+		uploadedErr != nil ||
+		ip == "" {
+		return nil, errors.New("malformed request")
+	}
+
+	return &announce{
+		Compact:    compact,
+		Downloaded: downloaded,
+		Event:      event,
+		IP:         ip,
+		Left:       left,
+		NumWant:    numWant,
+		Passkey:    passkey,
+		PeerID:     peerID,
+		Port:       port,
+		Uploaded:   uploaded,
+	}, nil
+}
+
+func requestedPeerCount(fallback int, pq *parsedQuery) int {
+	if numWantStr, exists := pq.Params["numWant"]; exists {
+		numWant, err := strconv.Atoi(numWantStr)
+		if err != nil {
+			return fallback
+		}
+		return numWant
+	}
+
+	return fallback
+}
+
+func requestedIP(r *http.Request, pq *parsedQuery) (string, error) {
+	if ip, ok := pq.Params["ip"]; ok {
+		return ip, nil
+	}
+
+	if ip, ok := pq.Params["ipv4"]; ok {
+		return ip, nil
+	}
+
+	if xRealIPs, ok := pq.Params["X-Real-Ip"]; ok {
+		return string(xRealIPs[0]), nil
+	}
+
+	portIndex := len(r.RemoteAddr) - 1
+	for ; portIndex >= 0; portIndex-- {
+		if r.RemoteAddr[portIndex] == ':' {
+			break
+		}
+	}
+
+	if portIndex != -1 {
+		return r.RemoteAddr[0:portIndex], nil
+	}
+
+	return "", errors.New("failed to parse IP address")
+}