Add following and unfollowing

internal/webserver/server.go

@@ -121,6 +121,10 @@ func (app *Application) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		app.ChangeSession(w, r)
 	case "timeline":
 		app.Timeline(w, r)
+	case "follow":
+		app.UserFollow(w, r)
+	case "unfollow":
+		app.UserUnfollow(w, r)
 	default:
 		app.UserFeed(w, r)
 	}
@@ -431,3 +435,50 @@ func parse_form(req *http.Request, result interface{}) error {
 	}
 	return nil
 }
+
+func (app *Application) UserFollow(w http.ResponseWriter, r *http.Request) {
+	app.traceLog.Printf("'UserFollow' handler (path: %q)", r.URL.Path)
+
+	if r.Method != "POST" {
+		http.Error(w, "Method not allowed", 405)
+		return
+	}
+
+	parts := strings.Split(strings.Trim(r.URL.Path, "/"), "/")
+	if len(parts) != 2 {
+		app.error_400_with_message(w, "Bad URL: "+r.URL.Path)
+		return
+	}
+	user, err := app.Profile.GetUserByHandle(scraper.UserHandle(parts[1]))
+	if err != nil {
+		app.error_404(w)
+		return
+	}
+
+	app.Profile.SetUserFollowed(&user, true)
+
+	app.buffered_render_basic_htmx(w, "following-button", user)
+}
+
+func (app *Application) UserUnfollow(w http.ResponseWriter, r *http.Request) {
+	app.traceLog.Printf("'UserUnfollow' handler (path: %q)", r.URL.Path)
+
+	if r.Method != "POST" {
+		http.Error(w, "Method not allowed", 405)
+		return
+	}
+
+	parts := strings.Split(strings.Trim(r.URL.Path, "/"), "/")
+	if len(parts) != 2 {
+		app.error_400_with_message(w, "Bad URL: "+r.URL.Path)
+		return
+	}
+	user, err := app.Profile.GetUserByHandle(scraper.UserHandle(parts[1]))
+	if err != nil {
+		app.error_404(w)
+		return
+	}
+
+	app.Profile.SetUserFollowed(&user, false)
+	app.buffered_render_basic_htmx(w, "following-button", user)
+}

internal/webserver/server_test.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"strings"
 
 	"github.com/andybalholm/cascadia"
 	"github.com/stretchr/testify/assert"
@@ -189,6 +190,55 @@ func TestTweetDetailInvalidNumber(t *testing.T) {
 	require.Equal(resp.StatusCode, 400)
 }
 
+// Follow and unfollow
+// -------------------
+
+func TestFollowUnfollow(t *testing.T) {
+	require := require.New(t)
+	assert := assert.New(t)
+
+	user, err := profile.GetUserByHandle("kwamurai")
+	require.NoError(err)
+	require.False(user.IsFollowed)
+
+	// Follow the user
+	resp := do_request(httptest.NewRequest("POST", "/follow/kwamurai", nil))
+	require.Equal(resp.StatusCode, 200)
+
+	root, err := html.Parse(resp.Body)
+	require.NoError(err)
+	button := cascadia.Query(root, selector("button"))
+	assert.Contains(button.Attr, html.Attribute{Key: "hx-post", Val: "/unfollow/kwamurai"})
+	assert.Equal(strings.TrimSpace(button.FirstChild.Data), "Unfollow")
+
+	user, err = profile.GetUserByHandle("kwamurai")
+	require.NoError(err)
+	require.True(user.IsFollowed)
+
+	// Unfollow the user
+	resp = do_request(httptest.NewRequest("POST", "/unfollow/kwamurai", nil))
+	require.Equal(resp.StatusCode, 200)
+
+	root, err = html.Parse(resp.Body)
+	require.NoError(err)
+	button = cascadia.Query(root, selector("button"))
+	assert.Contains(button.Attr, html.Attribute{Key: "hx-post", Val: "/follow/kwamurai"})
+	assert.Equal(strings.TrimSpace(button.FirstChild.Data), "Follow")
+
+	user, err = profile.GetUserByHandle("kwamurai")
+	require.NoError(err)
+	require.False(user.IsFollowed)
+}
+
+func TestFollowUnfollowPostOnly(t *testing.T) {
+	require := require.New(t)
+	resp := do_request(httptest.NewRequest("GET", "/follow/kwamurai", nil))
+	require.Equal(resp.StatusCode, 405)
+	resp = do_request(httptest.NewRequest("GET", "/unfollow/kwamurai", nil))
+	require.Equal(resp.StatusCode, 405)
+}
+
+
 // Static content
 // --------------
 

internal/webserver/static/styles.css

@@ -400,3 +400,12 @@ input[type="submit"] {
 .retweeted-by-label {
     margin: 0 0.2em;
 }
+
+.user-bio {
+    margin: 1.5em 0;
+}
+
+.followers-followees-container {
+    margin-top: 1em;
+    gap: 4em;
+}

internal/webserver/tpl/includes/following_button.tpl

@@ -0,0 +1,17 @@
+{{define "following-button"}}
+  {{if .IsFollowed}}
+    <button class="following-button"
+      hx-post="/unfollow/{{.Handle}}"
+      hx-swap="outerHTML"
+    >
+      Unfollow
+    </button>
+  {{else}}
+    <button class="following-button"
+      hx-post="/follow/{{.Handle}}"
+      hx-swap="outerHTML"
+    >
+      Follow
+    </button>
+  {{end}}
+{{end}}

internal/webserver/tpl/user_feed.tpl

@@ -8,8 +8,10 @@
     {{end}}
 
     <div class="user-feed-header-info-container">
+      <div class="row">
         {{template "author-info" $user}}
-      <button>{{if $user.IsFollowed}}Unfollow{{else}}Follow{{end}}</button>
+        {{template "following-button" $user}}
+      </div>
       <div class="user-bio">
         <span>{{$user.Bio}}</span>
       </div>