ntfy/cmd/subscribe.go
2021-12-22 10:21:59 +01:00

252 lines
8.2 KiB
Go

package cmd
import (
"errors"
"fmt"
"github.com/urfave/cli/v2"
"gopkg.in/yaml.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 loadConfigFromFile(filename)
}
u, _ := user.Current()
configFile := defaultClientRootConfigFile
if u.Uid != "0" {
configFile = util.ExpandHome(defaultClientUserConfigFile)
}
if s, _ := os.Stat(configFile); s != nil {
return loadConfigFromFile(configFile)
}
return client.NewConfig(), nil
}
func loadConfigFromFile(filename string) (*client.Config, error) {
b, err := os.ReadFile(filename)
if err != nil {
return nil, err
}
c := client.NewConfig()
if err := yaml.Unmarshal(b, c); err != nil {
return nil, err
}
return c, nil
}