From b91074ba9f523e3b2cbd31ed1915430c8c65502c Mon Sep 17 00:00:00 2001
From: Přemysl Eric Janouch <p@janouch.name>
Date: Tue, 26 Dec 2023 02:24:06 +0100
Subject: Indicate faulty requests better

---
 main.go           | 11 +++++++++--
 public/gallery.js | 26 ++++++++++++++++++++------
 public/style.css  |  1 +
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/main.go b/main.go
index c78f01e..04bc307 100644
--- a/main.go
+++ b/main.go
@@ -813,10 +813,14 @@ func handleAPIInfo(w http.ResponseWriter, r *http.Request) {
 
 	var err error
 	result.Width, result.Height, err = getImageDimensions(params.SHA1)
-	if err != nil {
+	if errors.Is(err, sql.ErrNoRows) {
+		http.Error(w, err.Error(), http.StatusNotFound)
+		return
+	} else if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+
 	result.Paths, err = getImagePaths(params.SHA1)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
@@ -920,7 +924,10 @@ func handleAPISimilar(w http.ResponseWriter, r *http.Request) {
 		SELECT width, height, dhash, IFNULL(thumbw, 0), IFNULL(thumbh, 0)
 		FROM image WHERE sha1 = ?`, params.SHA1).Scan(&width, &height, &dhash,
 		&result.Info.ThumbW, &result.Info.ThumbH)
-	if err != nil {
+	if errors.Is(err, sql.ErrNoRows) {
+		http.Error(w, err.Error(), http.StatusNotFound)
+		return
+	} else if err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
diff --git a/public/gallery.js b/public/gallery.js
index 299d372..9d3b067 100644
--- a/public/gallery.js
+++ b/public/gallery.js
@@ -1,14 +1,25 @@
 'use strict'
 
+let callActive = false
+let callFaulty = false
+
 function call(method, params) {
-	// TODO: Make it apparent when results result in errors:
-	//  - With responseType == "json", m.request() always expects JSON,
-	//    and error.message is null if it fails, but we can handle it manually.
-	//  - Go can wrap all errors into trivial strings before writing.
+	// XXX: At least with POST, unsuccessful requests result
+	// in catched errors containing Errors with a null message.
+	// This is an issue within XMLHttpRequest.
+	callActive++
 	return m.request({
 		method: "POST",
 		url: `/api/${method}`,
 		body: params,
+	}).then(result => {
+		callActive--
+		callFaulty = false
+		return result
+	}).catch(error => {
+		callActive--
+		callFaulty = true
+		throw error
 	})
 }
 
@@ -72,8 +83,11 @@ let Header = {
 		return m('.header', {}, [
 			m('nav', main),
 			m('nav', context),
-			// TODO: End it with an activity indicator.
-			m('.activity', '☺'),
+			callFaulty
+				? m('.activity.error[title=Error]', '●')
+				: callActive
+					? m('.activity[title=Busy]', '●')
+					: m('.activity[title=Idle]', '○'),
 		])
 	},
 }
diff --git a/public/style.css b/public/style.css
index e0fc004..1bdeb3f 100644
--- a/public/style.css
+++ b/public/style.css
@@ -22,6 +22,7 @@ a { color: inherit; }
 	background: #fff linear-gradient(#eee, #fff); }
 .header nav a.active, .header nav a:hover { padding-bottom: .4rem; }
 .header .activity { padding: .25rem .5rem; align-self: center; color: #fff; }
+.header .activity.error { color: #f00; }
 
 .sidebar { padding: .25rem .5rem; background: var(--shade-color);
 	border-right: 1px solid #ccc; overflow: auto;
-- 
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