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· 5 min read
Ivan Tsai

This article will load OpenStreetMap's map data into a Postgres database to facilitate the creation of a Tile Server for our later use.

OpenStreetMap Data

OpenStreetMap (OSM) is GIS data provider available under an open license. Similar to Wikipedia, anyone can edit and contribute to the data. As long as you credit the data source contributors in your service, OSM data is freely available for use under the ODbL license.

OSM data includes nodes (buildings, entrances, etc.), ways (routes, areas, etc.), and relations. For example, here's a segment of Zhongshan South Road data, indicating the nodes the route passes through, as well as the name and type of the route.

· 4 min read
Ivan Tsai

Recently started a new project because I wanted to create online maps using my own data. Services like Google Maps offer limited customization options, so this series of articles will guide you in building your own maps without relying on external services (though map data still needs to be obtained from a provider). It will cover both the backend map database and frontend rendering.

· 2 min read
Ivan Tsai

TypeScript SourceMap

We can generate Source Map files in TypeScript by setting compilerOptions.sourceMap = true in the TypeScript configuration tsconfig.json. This file allows tools like VS Code and Chrome debugger to map the compiled JS files back to the original TypeScript (TS) code.

However, if you receive error stacks from a production environment and want to quickly find the corresponding positions in the TS code, is there a way to do it manually?

· 3 min read
Ivan Tsai

Instance Metadata Service

Instance metadata is the information provided by AWS about your EC2 instances, including details like Host Name, Public IP, and more. This information can be accessed through the Metadata Service available at 169.254.169.254. This address is a link-local address that can only be accessed from within the EC2 instance. For example, you can retrieve the current Public IP using the following API:

curl http://169.254.169.254/latest/meta-data/public-ipv4

· 7 min read
Ivan Tsai

Recently, I introduced an Inversion of Control (IoC) container into a new project and found that most container libraries only provide documentation related to their own usage. There are fewer examples of actual implementations. In this article, we will use a well-known open-source project as an example to organize several good practices and the basic rules that should be followed.

· 6 min read
Ivan Tsai

What is a Bastion Host?

Usually, we place internal services such as databases or applications in private subnets. These machines cannot be accessed directly through a public IP. Instead, we use load balancers (ALB, ELB) to redirect traffic to the internal machines. This setup protects our services from external attacks and only allows access to services that truly need to be exposed externally.

· 3 min read
Ivan Tsai

What are Intermediate Certificates

Generally, a certificate authority (CA) does not issue user certificates using the actual root certificate. After all, there are so many end users, and having the root certificate online every day poses a significant risk. Instead, the CA issues a certificate using the root certificate and then uses that certificate to sign user certificates. This certificate is called an "intermediate certificate."