[PR #1620] [MERGED] fix(smtp): preserve line breaks in HTML emails #1667

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opened 2026-05-07 01:03:09 +02:00 by BreizhHardware · 0 comments

BreizhHardware commented

2026-05-07 01:03:09 +02:00

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📋 Pull Request Information

Original PR: https://github.com/binwiederhier/ntfy/pull/1620
Author: @uzkikh
Created: 2/21/2026
Status: ✅ Merged
Merged: 2/21/2026
Merged by: @binwiederhier

Base: main ← Head: fix/smtp-html-br-linebreaks

📝 Commits (1)

2e49938 fix(smtp): preserve
line breaks in HTML emails

📊 Changes

2 files changed (+41 additions, -4 deletions)

View changed files

📝 server/smtp_server.go (+4 -0)
📝 server/smtp_server_test.go (+37 -4)

📄 Description

Context

HTML-only emails (e.g. from Synology DSM 7.3 Task Scheduler) use   tags for line breaks. The existing implementation passed the raw HTML body to bluemonday with AddSpaceWhenStrippingTag(true), which replaces every tag including   with a space. This caused all notification content to appear on a single unreadable line.

The ntfy notification before the fix

Task Scheduler has completed a scheduled task. Task: daily-backup Start time: Mon, 01 Jan 2026 02:00:00 +0000 Current status: 0 (Normal) From MyNAS

The ntfy notification after the fix

Task Scheduler has completed a scheduled task.

Task: daily-backup
Start time: Mon, 01 Jan 2026 02:00:00 +0000
Current status: 0 (Normal)

From MyNAS

Steps to reproduce

# Start ntfy with SMTP enabled
ntfy serve --smtp-server-listen :25 --smtp-server-domain example.com

# Send an HTML-only email with <br> line breaks
swaks \
  --server 127.0.0.1 --port 25 \
  --from sender@example.com \
  --to ntfy-mytopic@example.com \
  --header "Content-Type: text/html; charset=utf-8" \
  --body "Line one.<BR>Line two.<BR><BR>Line three."

# Check the notification — all text appears on one line:
#    "Line one. Line two.  Line three."

Root cause

The readHTMLMailBody() function used bluemonday.StrictPolicy().AddSpaceWhenStrippingTag(true) which replaces all tags including   with spaces, discarding line break semantics.

Fix

Convert   tags to newlines before passing to bluemonday. The regex covers all variants:  ,  ,  ,  .

Tests

Updated TestSmtpBackend_HTMLOnly_FromDiskStation and TestSmtpBackend_HTMLEmail to reflect correct output
Added TestSmtpBackend_HTMLEmail_BrTagsPreserved covering the Synology Task Scheduler email format

Related to #690

_{🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.}

## 📋 Pull Request Information **Original PR:** https://github.com/binwiederhier/ntfy/pull/1620 **Author:** [@uzkikh](https://github.com/uzkikh) **Created:** 2/21/2026 **Status:** ✅ Merged **Merged:** 2/21/2026 **Merged by:** [@binwiederhier](https://github.com/binwiederhier) **Base:** `main` ← **Head:** `fix/smtp-html-br-linebreaks` --- ### 📝 Commits (1) - [`2e49938`](https://github.com/binwiederhier/ntfy/commit/2e499389fc7068d73b8249d97ee7e28c6b2a86c6) fix(smtp): preserve line breaks in HTML emails ### 📊 Changes **2 files changed** (+41 additions, -4 deletions) <details> <summary>View changed files</summary> 📝 `server/smtp_server.go` (+4 -0) 📝 `server/smtp_server_test.go` (+37 -4) </details> ### 📄 Description ## Context HTML-only emails (e.g. from Synology DSM 7.3 Task Scheduler) use ` ` tags for line breaks. The existing implementation passed the raw HTML body to bluemonday with `AddSpaceWhenStrippingTag(true)`, which replaces every tag including ` ` with a space. This caused all notification content to appear on a single unreadable line. ## The ntfy notification before the fix Task Scheduler has completed a scheduled task. Task: daily-backup Start time: Mon, 01 Jan 2026 02:00:00 +0000 Current status: 0 (Normal) From MyNAS ## The ntfy notification after the fix Task Scheduler has completed a scheduled task. Task: daily-backup Start time: Mon, 01 Jan 2026 02:00:00 +0000 Current status: 0 (Normal) From MyNAS ## Steps to reproduce ```bash # Start ntfy with SMTP enabled ntfy serve --smtp-server-listen :25 --smtp-server-domain example.com # Send an HTML-only email with line breaks swaks \ --server 127.0.0.1 --port 25 \ --from sender@example.com \ --to ntfy-mytopic@example.com \ --header "Content-Type: text/html; charset=utf-8" \ --body "Line one. Line two. Line three." # Check the notification — all text appears on one line: # "Line one. Line two. Line three." ``` ## Root cause The `readHTMLMailBody()` function used `bluemonday.StrictPolicy().AddSpaceWhenStrippingTag(true)` which replaces all tags including ` ` with spaces, discarding line break semantics. ## Fix Convert ` ` tags to newlines before passing to bluemonday. The regex covers all variants: ` `, ` `, ` `, ` `. ## Tests - Updated `TestSmtpBackend_HTMLOnly_FromDiskStation` and `TestSmtpBackend_HTMLEmail` to reflect correct output - Added `TestSmtpBackend_HTMLEmail_BrTagsPreserved` covering the Synology Task Scheduler email format Related to #690 --- 🔄 This issue represents a GitHub Pull Request. It cannot be merged through Gitea due to API limitations.