• Visit the Chinese site here, or click ‘Switch to Chinese’ at the left sidebar.

Introduction

In my previous post, I used QQ Mail as the notification service for ChangeDetection. That was just for quickly getting started with ChangeDetection, but it wasn’t necessary since there are several open-source notification systems available, such as ntfy. This article will walk through the installation and usage of ntfy, which is quite straightforward. However, I encountered some issues when integrating it with ChangeDetection, and this post will cover the solutions to those problems as well.

Introduction

Recently, I was waiting for a notification from a website, so I kept checking it periodically. Eventually, I found this too cumbersome and considered writing a web scraper to monitor it automatically. However, I soon discovered that there are many existing platforms available (so there’s no need to write any code). Most of these platforms offer free plans, but they only monitor static web pages, and you have to pay if you want to handle JSON data. So I started looking for open-source alternatives. This led me to the topic of this post — ChangeDetection.

ChangeDetection has two main functions: monitoring changes in URL content and notifying you of those changes. These two features cover most daily use cases.

Introduction

Recently, I found the process of writing blog posts with Hexo a bit cumbersome, so I wanted to automate it. The workflow automation includes: updating NPM dependencies, writing build scripts to make up for some deficiencies in Hexo, and using GitHub Actions to automatically deploy the site.

When I first started using Hexo, I wasn’t good at reading documentation and preferred following tutorials. After more than a year of using Hexo and over six months of deploying various open-source software, I decided to work on this improvement.

Introduction

If we want to store directory structures in a database, which type of database should be used? — Either NoSQL or RDBMS. If we choose NoSQL, we should select one that supports tree structures; if we choose RDBMS, the focus is on table design and query operations.

The key question is: What operations do we need to perform on the directory structure stored in the database? Obviously, these operations essentially mimic file operations in a file system.

• Operation 1: CRUD operations on single files/directories, such as copying, deleting, or moving a file/directory;
• Operation 2: Recursively traversing a directory;

Considering these two points is crucial for designing an efficient solution. This article presents solutions for both NoSQL and RDBMS, with a focus on the latter. Additionally, it explores using JSON as a solution.