Support follow/unfollow actions

Signed-off-by: Shin'ya Minazuki <shinyoukai@laidback.moe>

README.md

@@ -2,7 +2,7 @@
 A [yarn.social](https://yarn.social) client from the future
 
 ## Current status
-* [ ] Follow/Unfollow
+* [X] Follow/Unfollow
 * [X] Login
 * [X] Posting
 * [ ] Timeline

cmd/follow.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"git.laidback.moe/shinyoukai/mikuru"
+	"go.yarn.social/client"
+)
+
+var followCmd = &cobra.Command{
+	Use: "follow <NICK> <URL>",
+	Short: "Track a twtxt.txt feed, located in a Yarn pod or otherwise",
+	Run: func(_ *cobra.Command, args []string) {
+		cli, err := client.NewClient(
+			client.WithURI(mikuru.Config.Host),
+			client.WithToken(mikuru.Config.Token),
+		)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if len(args) != 2 {
+			log.Fatal("Not enough arguments")
+		}
+		nick := args[0]
+		url := args[1]
+
+		observe(cli, nick, url)
+		if err != nil {
+			log.Fatalf("Could not follow %s at %s\n", nick, url)
+		}
+	},
+}
+
+func init() {
+	mikuru.ConfInit()
+	rootCmd.AddCommand(followCmd)
+}
+
+func observe(cli *client.Client, nick, url string) error {
+	err := cli.Follow(nick, url)
+	if err != nil {
+		return err
+	}
+	return nil
+}

cmd/unfollow.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"git.laidback.moe/shinyoukai/mikuru"
+	"go.yarn.social/client"
+)
+
+var unfollowCmd = &cobra.Command{
+	Use: "unfollow <NICK>",
+	Short: "Cease to track a feed",
+	Run: func(_ *cobra.Command, args []string) {
+		cli, err := client.NewClient(
+			client.WithURI(mikuru.Config.Host),
+			client.WithToken(mikuru.Config.Token),
+		)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if len(args) != 1 {
+			log.Fatal("Not enough arguments")
+		}
+		nick := args[0]
+
+		leave_alone(cli, nick)
+		if err != nil {
+			log.Fatalf("Could not unfollow %s\n", nick)
+		}
+	},
+}
+
+func init() {
+	mikuru.ConfInit()
+	rootCmd.AddCommand(unfollowCmd)
+}
+
+func leave_alone(cli *client.Client, nick string) error {
+	err := cli.Unfollow(nick)
+	if err != nil {
+		return err
+	}
+	return nil
+}