package cmd import ( "errors" "fmt" "github.com/urfave/cli/v2" "heckel.io/ntfy/client" "heckel.io/ntfy/util" "log" "os" "os/exec" "os/user" "strings" ) var cmdSubscribe = &cli.Command{ Name: "subscribe", Aliases: []string{"sub"}, Usage: "Subscribe to one or more topics on a ntfy server", UsageText: "ntfy subscribe [OPTIONS..] [TOPIC]", Action: execSubscribe, Flags: []cli.Flag{ &cli.StringFlag{Name: "config", Aliases: []string{"c"}, Usage: "client config file"}, &cli.StringFlag{Name: "since", Aliases: []string{"s"}, Usage: "return events since `SINCE` (Unix timestamp, or all)"}, &cli.BoolFlag{Name: "from-config", Aliases: []string{"C"}, Usage: "read subscriptions from config file (service mode)"}, &cli.BoolFlag{Name: "poll", Aliases: []string{"p"}, Usage: "return events and exit, do not listen for new events"}, &cli.BoolFlag{Name: "scheduled", Aliases: []string{"sched", "S"}, Usage: "also return scheduled/delayed events"}, &cli.BoolFlag{Name: "verbose", Aliases: []string{"v"}, Usage: "print verbose output"}, }, Description: `Subscribe to a topic from a ntfy server, and either print or execute a command for every arriving message. There are 3 modes in which the command can be run: ntfy subscribe TOPIC This prints the JSON representation of every incoming message. It is useful when you have a command that wants to stream-read incoming JSON messages. Unless --poll is passed, this command stays open forever. Examples: ntfy subscribe mytopic # Prints JSON for incoming messages for ntfy.sh/mytopic ntfy sub home.lan/backups # Subscribe to topic on different server ntfy sub --poll home.lan/backups # Just query for latest messages and exit ntfy subscribe TOPIC COMMAND This executes COMMAND for every incoming messages. The message fields are passed to the command as environment variables: Variable Aliases Description --------------- --------------- ----------------------------------- $NTFY_ID $id Unique message ID $NTFY_TIME $time Unix timestamp of the message delivery $NTFY_TOPIC $topic Topic name $NTFY_MESSAGE $message, $m Message body $NTFY_TITLE $title, $t Message title $NTFY_PRIORITY $priority, $p Message priority (1=min, 5=max) $NTFY_TAGS $tags, $ta Message tags (comma separated list) Examples: ntfy sub mytopic 'notify-send "$m"' # Execute command for incoming messages ntfy sub topic1 /my/script.sh # Execute script for incoming messages ntfy subscribe --from-config Service mode (used in ntfy-client.service). This reads the config file (/etc/ntfy/client.yml or ~/.config/ntfy/client.yml) and sets up subscriptions for every topic in the "subscribe:" block (see config file). Examples: ntfy sub --from-config # Read topics from config file ntfy sub --config=/my/client.yml --from-config # Read topics from alternate config file The default config file for all client commands is /etc/ntfy/client.yml (if root user), or ~/.config/ntfy/client.yml for all other users.`, } func execSubscribe(c *cli.Context) error { // Read config and options conf, err := loadConfig(c) if err != nil { return err } cl := client.New(conf) since := c.String("since") poll := c.Bool("poll") scheduled := c.Bool("scheduled") fromConfig := c.Bool("from-config") topic := c.Args().Get(0) command := c.Args().Get(1) if !fromConfig { conf.Subscribe = nil // wipe if --from-config not passed } var options []client.SubscribeOption if since != "" { options = append(options, client.WithSince(since)) } if poll { options = append(options, client.WithPoll()) } if scheduled { options = append(options, client.WithScheduled()) } if topic == "" && len(conf.Subscribe) == 0 { return errors.New("must specify topic, type 'ntfy subscribe --help' for help") } // Execute poll or subscribe if poll { return doPoll(c, cl, conf, topic, command, options...) } return doSubscribe(c, cl, conf, topic, command, options...) } func doPoll(c *cli.Context, cl *client.Client, conf *client.Config, topic, command string, options ...client.SubscribeOption) error { for _, s := range conf.Subscribe { // may be nil if err := doPollSingle(c, cl, s.Topic, s.Command, options...); err != nil { return err } } if topic != "" { if err := doPollSingle(c, cl, topic, command, options...); err != nil { return err } } return nil } func doPollSingle(c *cli.Context, cl *client.Client, topic, command string, options ...client.SubscribeOption) error { messages, err := cl.Poll(topic, options...) if err != nil { return err } for _, m := range messages { printMessageOrRunCommand(c, m, command) } return nil } func doSubscribe(c *cli.Context, cl *client.Client, conf *client.Config, topic, command string, options ...client.SubscribeOption) error { commands := make(map[string]string) // Subscription ID -> command for _, s := range conf.Subscribe { // May be nil topicOptions := append(make([]client.SubscribeOption, 0), options...) for filter, value := range s.If { topicOptions = append(topicOptions, client.WithFilter(filter, value)) } subscriptionID := cl.Subscribe(s.Topic, topicOptions...) commands[subscriptionID] = s.Command } if topic != "" { subscriptionID := cl.Subscribe(topic, options...) commands[subscriptionID] = command } for m := range cl.Messages { command, ok := commands[m.SubscriptionID] if !ok { continue } printMessageOrRunCommand(c, m, command) } return nil } func printMessageOrRunCommand(c *cli.Context, m *client.Message, command string) { if m.Event != client.MessageEvent { return } if command != "" { runCommand(c, command, m) } else { fmt.Fprintln(c.App.Writer, m.Raw) } } func runCommand(c *cli.Context, command string, m *client.Message) { if err := runCommandInternal(c, command, m); err != nil { fmt.Fprintf(c.App.ErrWriter, "Command failed: %s\n", err.Error()) } } func runCommandInternal(c *cli.Context, command string, m *client.Message) error { scriptFile, err := createTmpScript(command) if err != nil { return err } defer os.Remove(scriptFile) verbose := c.Bool("verbose") if verbose { log.Printf("[%s] Executing: %s (for message: %s)", collapseTopicURL(m.TopicURL), command, m.Raw) } cmd := exec.Command("sh", "-c", scriptFile) cmd.Stdin = c.App.Reader cmd.Stdout = c.App.Writer cmd.Stderr = c.App.ErrWriter cmd.Env = envVars(m) return cmd.Run() } func createTmpScript(command string) (string, error) { scriptFile := fmt.Sprintf("%s/ntfy-subscribe-%s.sh.tmp", os.TempDir(), util.RandomString(10)) script := fmt.Sprintf("#!/bin/sh\n%s", command) if err := os.WriteFile(scriptFile, []byte(script), 0700); err != nil { return "", err } return scriptFile, nil } func envVars(m *client.Message) []string { env := os.Environ() env = append(env, envVar(m.ID, "NTFY_ID", "id")...) env = append(env, envVar(m.Topic, "NTFY_TOPIC", "topic")...) env = append(env, envVar(fmt.Sprintf("%d", m.Time), "NTFY_TIME", "time")...) env = append(env, envVar(m.Message, "NTFY_MESSAGE", "message", "m")...) env = append(env, envVar(m.Title, "NTFY_TITLE", "title", "t")...) env = append(env, envVar(fmt.Sprintf("%d", m.Priority), "NTFY_PRIORITY", "priority", "prio", "p")...) env = append(env, envVar(strings.Join(m.Tags, ","), "NTFY_TAGS", "tags", "tag", "ta")...) return env } func envVar(value string, vars ...string) []string { env := make([]string, 0) for _, v := range vars { env = append(env, fmt.Sprintf("%s=%s", v, value)) } return env } func loadConfig(c *cli.Context) (*client.Config, error) { filename := c.String("config") if filename != "" { return client.LoadConfig(filename) } u, _ := user.Current() configFile := defaultClientRootConfigFile if u.Uid != "0" { configFile = util.ExpandHome(defaultClientUserConfigFile) } if s, _ := os.Stat(configFile); s != nil { return client.LoadConfig(configFile) } return client.NewConfig(), nil }