moth/cmd/mothd/server.go

252 lines
6.9 KiB
Go

package main
import (
"fmt"
"io"
"strconv"
"time"
"github.com/dirtbags/moth/pkg/award"
)
// Category represents a puzzle category.
type Category struct {
Name string
Puzzles []int
}
// ReadSeekCloser defines a struct that can read, seek, and close.
type ReadSeekCloser interface {
io.Reader
io.Seeker
io.Closer
}
// Configuration stores information about server configuration.
type Configuration struct {
Devel bool
}
// StateExport is given to clients requesting the current state.
type StateExport struct {
Config Configuration
Messages string
TeamNames map[string]string
PointsLog award.List
Puzzles map[string][]int
}
// PuzzleProvider defines what's required to provide puzzles.
type PuzzleProvider interface {
Open(cat string, points int, path string) (ReadSeekCloser, time.Time, error)
Inventory() []Category
CheckAnswer(cat string, points int, answer string) (bool, error)
Mothball(cat string, w io.Writer) error
Maintainer
}
// ThemeProvider defines what's required to provide a theme.
type ThemeProvider interface {
Open(path string) (ReadSeekCloser, time.Time, error)
Maintainer
}
// StateProvider defines what's required to provide MOTH state.
type StateProvider interface {
Messages() string
PointsLog() award.List
TeamName(teamID string) (string, error)
SetTeamName(teamID, teamName string) error
AwardPoints(teamID string, cat string, points int) error
LogEvent(msg string)
Maintainer
}
// Maintainer is something that can be maintained.
type Maintainer interface {
// Maintain is the maintenance loop.
// It will only be called once, when execution begins.
// It's okay to just exit if there's no maintenance to be done.
Maintain(updateInterval time.Duration)
}
// MothServer gathers together the providers that make up a MOTH server.
type MothServer struct {
PuzzleProviders []PuzzleProvider
Theme ThemeProvider
State StateProvider
Config Configuration
}
// NewMothServer returns a new MothServer.
func NewMothServer(config Configuration, theme ThemeProvider, state StateProvider, puzzleProviders ...PuzzleProvider) *MothServer {
return &MothServer{
Config: config,
PuzzleProviders: puzzleProviders,
Theme: theme,
State: state,
}
}
// NewHandler returns a new http.RequestHandler for the provided teamID.
func (s *MothServer) NewHandler(participantID, teamID string) MothRequestHandler {
return MothRequestHandler{
MothServer: s,
participantID: participantID,
teamID: teamID,
}
}
// MothRequestHandler provides http.RequestHandler for a MothServer.
type MothRequestHandler struct {
*MothServer
participantID string
teamID string
}
// PuzzlesOpen opens a file associated with a puzzle.
// BUG(neale): Multiple providers with the same category name are not detected or handled well.
func (mh *MothRequestHandler) PuzzlesOpen(cat string, points int, path string) (r ReadSeekCloser, ts time.Time, err error) {
export := mh.exportStateIfRegistered(true)
found := false
for _, p := range export.Puzzles[cat] {
if p == points {
found = true
}
}
if !found {
return nil, time.Time{}, fmt.Errorf("Puzzle does not exist or is locked")
}
// Try every provider until someone doesn't return an error
for _, provider := range mh.PuzzleProviders {
r, ts, err = provider.Open(cat, points, path)
if err != nil {
return r, ts, err
}
}
return
}
// CheckAnswer returns an error if answer is not a correct answer for puzzle points in category cat
func (mh *MothRequestHandler) CheckAnswer(cat string, points int, answer string) error {
correct := false
for _, provider := range mh.PuzzleProviders {
if ok, err := provider.CheckAnswer(cat, points, answer); err != nil {
return err
} else if ok {
correct = true
}
}
if !correct {
return fmt.Errorf("Incorrect answer")
}
msg := fmt.Sprintf("GOOD %s %s %s %d", mh.participantID, mh.teamID, cat, points)
mh.State.LogEvent(msg)
if err := mh.State.AwardPoints(mh.teamID, cat, points); err != nil {
return fmt.Errorf("Error awarding points: %s", err)
}
return nil
}
// ThemeOpen opens a file from a theme.
func (mh *MothRequestHandler) ThemeOpen(path string) (ReadSeekCloser, time.Time, error) {
return mh.Theme.Open(path)
}
// Register associates a team name with a team ID.
func (mh *MothRequestHandler) Register(teamName string) error {
// BUG(neale): Register returns an error if a team is already registered; it may make more sense to return success
if teamName == "" {
return fmt.Errorf("Empty team name")
}
return mh.State.SetTeamName(mh.teamID, teamName)
}
// ExportState anonymizes team IDs and returns StateExport.
// If a teamID has been specified for this MothRequestHandler,
// the anonymized team name for this teamID has the special value "self".
// If not, the puzzles list is empty.
func (mh *MothRequestHandler) ExportState() *StateExport {
return mh.exportStateIfRegistered(false)
}
func (mh *MothRequestHandler) exportStateIfRegistered(override bool) *StateExport {
export := StateExport{}
export.Config = mh.Config
teamName, err := mh.State.TeamName(mh.teamID)
registered := override || (err == nil)
export.Messages = mh.State.Messages()
export.TeamNames = map[string]string{"self": teamName}
// Anonymize team IDs in points log, and write out team names
pointsLog := mh.State.PointsLog()
exportIDs := map[string]string{mh.teamID: "self"}
maxSolved := map[string]int{}
export.PointsLog = make(award.List, len(pointsLog))
for logno, awd := range pointsLog {
if id, ok := exportIDs[awd.TeamID]; ok {
awd.TeamID = id
} else {
exportID := strconv.Itoa(logno)
name, _ := mh.State.TeamName(awd.TeamID)
awd.TeamID = exportID
exportIDs[awd.TeamID] = awd.TeamID
export.TeamNames[exportID] = name
}
export.PointsLog[logno] = awd
// Record the highest-value unlocked puzzle in each category
if awd.Points > maxSolved[awd.Category] {
maxSolved[awd.Category] = awd.Points
}
}
export.Puzzles = make(map[string][]int)
if registered {
// We used to hand this out to everyone,
// but then we got a bad reputation on some secretive blacklist,
// and now the Navy can't register for events.
for _, provider := range mh.PuzzleProviders {
for _, category := range provider.Inventory() {
// Append sentry (end of puzzles)
allPuzzles := append(category.Puzzles, 0)
max := maxSolved[category.Name]
puzzles := make([]int, 0, len(allPuzzles))
for i, val := range allPuzzles {
puzzles = allPuzzles[:i+1]
if !mh.Config.Devel && (val > max) {
break
}
}
export.Puzzles[category.Name] = puzzles
}
}
}
return &export
}
// Mothball generates a mothball for the given category.
func (mh *MothRequestHandler) Mothball(cat string, w io.Writer) error {
var err error
if !mh.Config.Devel {
return fmt.Errorf("Cannot mothball in production mode")
}
for _, provider := range mh.PuzzleProviders {
if err = provider.Mothball(cat, w); err == nil {
return nil
}
}
return err
}