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package hotline
import (
"cmp"
"encoding/binary"
"fmt"
"golang.org/x/crypto/bcrypt"
"io"
"log/slog"
"slices"
"strings"
"sync"
)
// ClientConn represents a client connected to a Server
type ClientConn struct {
Connection io.ReadWriteCloser
RemoteAddr string
ID [2]byte
Icon []byte
flagsMU sync.Mutex
Flags UserFlags
UserName []byte
Account *Account
IdleTime int
Server *Server
Version []byte
Idle bool
AutoReply []byte
transfersMU sync.Mutex
transfers map[int]map[[4]byte]*FileTransfer
logger *slog.Logger
sync.Mutex
}
func (cc *ClientConn) sendAll(t [2]byte, fields ...Field) {
for _, c := range cc.Server.Clients {
cc.Server.outbox <- NewTransaction(t, c.ID, fields...)
}
}
func (cc *ClientConn) handleTransaction(transaction Transaction) {
if handler, ok := TransactionHandlers[transaction.Type]; ok {
cc.logger.Debug("Received Transaction", "RequestType", transaction.Type)
for _, t := range handler(cc, &transaction) {
cc.Server.outbox <- t
}
}
cc.Server.mux.Lock()
defer cc.Server.mux.Unlock()
if transaction.Type != TranKeepAlive {
// reset the user idle timer
cc.IdleTime = 0
// if user was previously idle, mark as not idle and notify other connected clients that
// the user is no longer away
if cc.Idle {
cc.Flags.Set(UserFlagAway, 0)
cc.Idle = false
cc.sendAll(
TranNotifyChangeUser,
NewField(FieldUserID, cc.ID[:]),
NewField(FieldUserFlags, cc.Flags[:]),
NewField(FieldUserName, cc.UserName),
NewField(FieldUserIconID, cc.Icon),
)
}
}
}
func (cc *ClientConn) Authenticate(login string, password []byte) bool {
if account, ok := cc.Server.Accounts[login]; ok {
return bcrypt.CompareHashAndPassword([]byte(account.Password), password) == nil
}
return false
}
// Authorize checks if the user account has the specified permission
func (cc *ClientConn) Authorize(access int) bool {
cc.Lock()
defer cc.Unlock()
if cc.Account == nil {
return false
}
return cc.Account.Access.IsSet(access)
}
// Disconnect notifies other clients that a client has disconnected
func (cc *ClientConn) Disconnect() {
cc.Server.mux.Lock()
delete(cc.Server.Clients, cc.ID)
cc.Server.mux.Unlock()
for _, t := range cc.notifyOthers(NewTransaction(TranNotifyDeleteUser, [2]byte{}, NewField(FieldUserID, cc.ID[:]))) {
cc.Server.outbox <- t
}
if err := cc.Connection.Close(); err != nil {
cc.Server.Logger.Error("error closing client connection", "RemoteAddr", cc.RemoteAddr)
}
}
// notifyOthers sends transaction t to other clients connected to the server
func (cc *ClientConn) notifyOthers(t Transaction) (trans []Transaction) {
cc.Server.mux.Lock()
defer cc.Server.mux.Unlock()
for _, c := range cc.Server.Clients {
if c.ID != cc.ID {
t.clientID = c.ID
trans = append(trans, t)
}
}
return trans
}
// NewReply returns a reply Transaction with fields for the ClientConn
func (cc *ClientConn) NewReply(t *Transaction, fields ...Field) Transaction {
return Transaction{
IsReply: 1,
ID: t.ID,
clientID: cc.ID,
Fields: fields,
}
}
// NewErrReply returns an error reply Transaction with errMsg
func (cc *ClientConn) NewErrReply(t *Transaction, errMsg string) []Transaction {
return []Transaction{
{
clientID: cc.ID,
IsReply: 1,
ID: t.ID,
ErrorCode: [4]byte{0, 0, 0, 1},
Fields: []Field{
NewField(FieldError, []byte(errMsg)),
},
},
}
}
var clientSortFunc = func(a, b *ClientConn) int {
return cmp.Compare(
binary.BigEndian.Uint16(a.ID[:]),
binary.BigEndian.Uint16(b.ID[:]),
)
}
// sortedClients is a utility function that takes a map of *ClientConn and returns a sorted slice of the values.
// The purpose of this is to ensure that the ordering of client connections is deterministic so that test assertions work.
func sortedClients(unsortedClients map[[2]byte]*ClientConn) (clients []*ClientConn) {
for _, c := range unsortedClients {
clients = append(clients, c)
}
slices.SortFunc(clients, clientSortFunc)
return clients
}
const userInfoTemplate = `Nickname: %s
Name: %s
Account: %s
Address: %s
-------- File Downloads ---------
%s
------- Folder Downloads --------
%s
--------- File Uploads ----------
%s
-------- Folder Uploads ---------
%s
------- Waiting Downloads -------
%s
`
func formatDownloadList(fts map[[4]byte]*FileTransfer) (s string) {
if len(fts) == 0 {
return "None.\n"
}
for _, dl := range fts {
s += dl.String()
}
return s
}
func (cc *ClientConn) String() string {
cc.transfersMU.Lock()
defer cc.transfersMU.Unlock()
template := fmt.Sprintf(
userInfoTemplate,
cc.UserName,
cc.Account.Name,
cc.Account.Login,
cc.RemoteAddr,
formatDownloadList(cc.transfers[FileDownload]),
formatDownloadList(cc.transfers[FolderDownload]),
formatDownloadList(cc.transfers[FileUpload]),
formatDownloadList(cc.transfers[FolderUpload]),
"None.\n",
)
return strings.ReplaceAll(template, "\n", "\r")
}
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