email: optional logo image in the header

A configurable logo URL renders as an image beside the brand name in the
email header (falling back to the brand text when unset). Email clients
need a hosted image, so it takes a URL rather than an inline asset.

modules/nickserv/resetpass.rs

@@ -19,7 +19,7 @@ pub fn handle(me: &str, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, db:
                 return;
             };
             let code = db.issue_code(&canonical, CodeKind::Reset);
-            let mail = crate::email::reset(db.email_brand(), db.email_accent(), &canonical, &code);
+            let mail = crate::email::reset(db.email_brand(), db.email_accent(), db.email_logo(), &canonical, &code);
             ctx.send_email(email, mail.subject, mail.text, Some(mail.html));
             ctx.notice(me, from.uid, format!("A reset code has been emailed to the address on file for \x02{canonical}\x02."));
         }

src/config.rs

@@ -27,6 +27,10 @@ pub struct Email {
     // Accent colour (any CSS colour) for the email template.
     #[serde(default = "default_accent")]
     pub accent: String,
+    // Optional logo image URL shown in the email header (must be a hosted image;
+    // email clients don't render inline SVG or data URIs).
+    #[serde(default)]
+    pub logo: String,
 }
 
 fn default_brand() -> String {

src/email.rs

@@ -9,8 +9,23 @@ pub struct Mail {
 
 const BASE: &str = include_str!("../templates/email/base.html");
 
-fn render(brand: &str, accent: &str, title: &str, message: &str, code: &str, note: &str) -> String {
-    BASE.replace("{{brand}}", &escape(brand))
+// The masthead: a logo image beside the brand name when a logo URL is set,
+// otherwise the brand name as an accent eyebrow.
+fn brand_mark(brand: &str, accent: &str, logo: &str) -> String {
+    let (brand, accent) = (escape(brand), escape(accent));
+    if logo.is_empty() {
+        format!("<span style=\"font-size:12px;font-weight:700;letter-spacing:1.6px;text-transform:uppercase;color:{accent};\">{brand}</span>")
+    } else {
+        format!(
+            "<img src=\"{}\" width=\"40\" height=\"40\" alt=\"\" style=\"display:inline-block;border-radius:9px;vertical-align:middle;\"><span style=\"display:inline-block;margin-left:12px;vertical-align:middle;font-size:18px;font-weight:800;letter-spacing:.2px;color:#0f172a;\">{brand}</span>",
+            escape(logo)
+        )
+    }
+}
+
+fn render(brand: &str, accent: &str, logo: &str, title: &str, message: &str, code: &str, note: &str) -> String {
+    BASE.replace("{{brand_mark}}", &brand_mark(brand, accent, logo))
+        .replace("{{brand}}", &escape(brand))
         .replace("{{accent}}", &escape(accent))
         .replace("{{title}}", &escape(title))
         .replace("{{message}}", &escape(message))
@@ -18,7 +33,7 @@ fn render(brand: &str, accent: &str, title: &str, message: &str, code: &str, not
         .replace("{{note}}", &escape(note))
 }
 
-pub fn reset(brand: &str, accent: &str, account: &str, code: &str) -> Mail {
+pub fn reset(brand: &str, accent: &str, logo: &str, account: &str, code: &str) -> Mail {
     Mail {
         subject: format!("Password reset for {account}"),
         text: format!(
@@ -27,6 +42,7 @@ pub fn reset(brand: &str, accent: &str, account: &str, code: &str) -> Mail {
         html: render(
             brand,
             accent,
+            logo,
             "Password reset",
             &format!("Use this code to reset the password for your account {account}."),
             code,
@@ -35,7 +51,7 @@ pub fn reset(brand: &str, accent: &str, account: &str, code: &str) -> Mail {
     }
 }
 
-pub fn confirm(brand: &str, accent: &str, account: &str, code: &str) -> Mail {
+pub fn confirm(brand: &str, accent: &str, logo: &str, account: &str, code: &str) -> Mail {
     Mail {
         subject: format!("Confirm your {account} registration"),
         text: format!(
@@ -44,6 +60,7 @@ pub fn confirm(brand: &str, accent: &str, account: &str, code: &str) -> Mail {
         html: render(
             brand,
             accent,
+            logo,
             "Confirm your account",
             &format!("Welcome! Confirm the email for your account {account} with the code below."),
             code,

src/engine/db.rs

@@ -456,9 +456,10 @@ pub struct Db {
     pub(crate) scram_iterations: u32,
     // Whether outbound email is configured, so email features can gate themselves.
     email_enabled: bool,
-    // Display name and accent colour for email templates.
+    // Display name, accent colour, and optional logo URL for email templates.
     email_brand: String,
     email_accent: String,
+    email_logo: String,
     // Node-local, non-persisted email codes: account -> (purpose, code, expiry).
     codes: HashMap<String, (CodeKind, String, Instant)>,
 }
@@ -507,7 +508,7 @@ impl Db {
             apply(&mut accounts, &mut channels, &mut grouped, event);
         }
         tracing::info!(accounts = accounts.len(), channels = channels.len(), "account store loaded");
-        Self { accounts, channels, grouped, log, scram_iterations: scram::DEFAULT_ITERATIONS, email_enabled: false, email_brand: "Network Services".to_string(), email_accent: "#4f46e5".to_string(), codes: HashMap::new() }
+        Self { accounts, channels, grouped, log, scram_iterations: scram::DEFAULT_ITERATIONS, email_enabled: false, email_brand: "Network Services".to_string(), email_accent: "#4f46e5".to_string(), email_logo: String::new(), codes: HashMap::new() }
     }
 
     /// Fold an entry authored by another node into the store — the services-side
@@ -744,6 +745,11 @@ impl Db {
         &self.email_accent
     }
 
+    /// Logo image URL for email templates (empty = show the brand name as text).
+    pub fn email_logo(&self) -> &str {
+        &self.email_logo
+    }
+
     pub fn set_email_brand(&mut self, brand: &str) {
         self.email_brand = brand.to_string();
     }
@@ -752,6 +758,10 @@ impl Db {
         self.email_accent = accent.to_string();
     }
 
+    pub fn set_email_logo(&mut self, logo: &str) {
+        self.email_logo = logo.to_string();
+    }
+
     /// Issue a fresh emailed code for `account` and purpose, valid for 15 minutes.
     pub fn issue_code(&mut self, account: &str, kind: CodeKind) -> String {
         let code = gen_code();

src/engine/mod.rs

@@ -548,7 +548,7 @@ impl Engine {
         if ok && !self.db.is_verified(account) {
             if let (Some(addr), RegReply::NickServ { agent, uid, .. }) = (addr, &reply) {
                 let code = self.db.issue_code(account, db::CodeKind::Confirm);
-                let mail = crate::email::confirm(self.db.email_brand(), self.db.email_accent(), account, &code);
+                let mail = crate::email::confirm(self.db.email_brand(), self.db.email_accent(), self.db.email_logo(), account, &code);
                 out.push(NetAction::SendEmail { to: addr, subject: mail.subject, text: mail.text, html: Some(mail.html) });
                 out.push(NetAction::Notice { from: agent.clone(), to: uid.clone(), text: "A confirmation code has been emailed to you. Confirm with \x02CONFIRM <code>\x02.".to_string() });
             }

src/main.rs

@@ -60,6 +60,7 @@ async fn main() -> Result<()> {
     if let Some(email) = &cfg.email {
         db.set_email_brand(&email.brand);
         db.set_email_accent(&email.accent);
+        db.set_email_logo(&email.logo);
     }
     let engine = Arc::new(Mutex::new(Engine::new(services, db)));
 

templates/email/base.html

@@ -14,7 +14,7 @@
   <tr><td style="height:5px;background:{{accent}};font-size:0;line-height:0;">&nbsp;</td></tr>
 
   <tr><td style="padding:30px 36px 0;">
-    <span style="font-size:12px;font-weight:700;letter-spacing:1.6px;text-transform:uppercase;color:{{accent}};">{{brand}}</span>
+    <div style="margin-bottom:6px;">{{brand_mark}}</div>
     <h1 style="margin:16px 0 10px;font-size:23px;line-height:1.3;font-weight:800;color:#0f172a;">{{title}}</h1>
     <p style="margin:0;font-size:15px;line-height:1.65;color:#475569;">{{message}}</p>
   </td></tr>