Why Adding 86,400 Seconds Does Not Always Equal One Day in Code

·2 views

A software developer has highlighted a subtle but impactful bug that affects date arithmetic in production systems twice a year, during Daylight Saving Time (DST) transitions. The issue arises because a spring-forward day is only 82,800 seconds long and a fall-back day stretches to 90,000 seconds, meaning adding exactly 86,400 seconds to a timestamp can land on the wrong calendar day. The problem affects multiple programming languages, including JavaScript, Java, Python, Go, and SQL, each handling the distinction between duration-based and calendar-aware date operations differently. Developers are advised to store timestamps in UTC or epoch seconds and perform calendar-day calculations using timezone-aware methods tied to a full zone ruleset rather than a fixed offset. Including DST boundary dates in automated test suites is recommended to catch these errors before they reach production.

Read the full story at DEV Community

This is an AI-generated summary. ShortSingh links to the original source for the complete article.

Discussion (0)

How to Enable Automatic Security Updates on Debian 13 with unattended-upgrades

The unattended-upgrades package allows Debian 13 servers to automatically download and install security updates daily without manual intervention. It is configured using dpkg-reconfigure and a settings file at /etc/apt/apt.conf.d/50unattended-upgrades, where administrators can fine-tune which update sources are included. By default, the tool covers both Debian security patches and conservative stable point-release updates, while larger software upgrades remain under manual control. Administrators can also configure automatic cleanup of unused kernels and dependencies to prevent the /boot partition from filling up. The tool supports optional automatic reboots at a scheduled time for kernel updates, though this setting requires a deliberate choice based on server availability requirements.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

HTTP 200 Status Code Alone Cannot Confirm a Credential or Secret Leak

A 200 OK response from a server only confirms that a body was returned, not that sensitive data was exposed, according to a security-focused analysis published on DEV Community. Many web applications return identical HTML shells, login redirects, or branded error pages with a 200 status, making the code unreliable as standalone evidence. Investigators are advised to send a control request to a random nonexistent path and compare its structure, content type, and URL with the suspected file to determine if the response is merely a fallback. Any credible finding should include a format signature specific to the expected resource — such as the structure of an environment file or backup archive — rather than generic terms like 'password'. Security reports should clearly separate observed data from inferred conclusions, and sensitive credentials should never be copied into public issues or screenshots.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

How to Configure Traefik v3 as a Reverse Proxy with Automatic HTTPS

Traefik v3 can be set up as a central reverse proxy that listens on ports 80 and 443, automatically routing incoming requests to the correct Docker containers based on domain labels. It integrates with Let's Encrypt to obtain and renew TLS certificates automatically, eliminating the need for manual certificate management. Requests flow through four stages — Entrypoint, Router, Middleware, and Service — a structure that also helps with debugging when routing fails. A shared Docker proxy network, optionally configured with IPv6 support, must be created in advance so Traefik can communicate with all connected containers. A valid, publicly resolving domain pointing to the server is a prerequisite, as Let's Encrypt requires HTTP access to verify domain ownership before issuing certificates.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

Streaming Materialized Views Offer a Simpler Path to Live Read Models in 2026

Streaming materialized views allow developers to declare read models in SQL, with a streaming engine maintaining them incrementally as new events arrive, eliminating the need for custom consumer code or separate serving layers. This approach is particularly well-suited for Change Data Capture workloads, where upstream row-level changes must be reflected in near real-time for applications and dashboards. Two leading engines are compared: RisingWave, favored for its SQL-first experience, built-in CDC connectors, and simplified operations, and Apache Flink, preferred for complex, code-centric workloads requiring advanced event-time semantics and a polyglot serving layer. Despite their advantages, streaming materialized views still carry operational concerns, including unbounded state growth, schema evolution challenges, and reprocessing semantics that teams must plan for carefully. The guidance advises teams to evaluate latency requirements, state footprint, and existing infrastructure investments before choosing between the two approaches.

0 comments Read more at DEV Community