# 521xueweihan/github520 architecture

> Architecture diagram of the GitHub repository 521xueweihan/github520, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-11-09). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/521xueweihan/github520
- Repository: https://github.com/521xueweihan/github520

## Overview

GitHub520 generates and publishes host-to-IP mappings intended to improve GitHub access and image loading. Its main workflow resolves configured GitHub domains, combines DNS answers, selects a low-latency address, and writes hosts data; a separate updater imports the published JSON and regenerates outputs. Users or host-management tools consume the published hosts file. The source excerpts show the resolver and writers, while README statements establish the published endpoints and usage; the scheduled automation’s internal wiring is not shown.

Main entry points: [`fetch_ips.py`](https://github.com/521xueweihan/github520/blob/main/fetch_ips.py) (Domain Resolver), [`common.py`](https://github.com/521xueweihan/github520/blob/main/common.py) (Hosts Formatter), [`hosts`](https://github.com/521xueweihan/github520/blob/main/hosts) (hosts), [`update_ips.py`](https://github.com/521xueweihan/github520/blob/main/update_ips.py) (JSON Importer)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_ip_discovery["IP Discovery"]
  node_github_domains["GitHub Domains"]
  node_dns_services["DNS Services"]
  node_https_targets["HTTPS Targets"]
  node_ip_resolver["Domain Resolver<br/>[fetch_ips.py]"]
  node_ip_selector["IP Selector<br/>[fetch_ips.py]"]
end

subgraph group_content_generation["Content Generation"]
  node_hosts_formatter["Hosts Formatter<br/>[common.py]"]
  node_published_json["Published Hosts JSON"]
  node_remote_json["Remote Hosts JSON"]
  node_json_importer["JSON Importer<br/>[update_ips.py]"]
  node_hosts_file["hosts"]
  node_hosts_json["hosts.json<br/>[hosts.json]"]
  node_readme_output["README Output<br/>[README.md]"]
end

subgraph group_host_consumption["Host Consumption"]
  node_host_tools["Host Tools"]
  node_raw_hosts_service["Raw Hosts Service"]
end

node_user(("User"))

node_ip_resolver -->|"resolves"| node_github_domains
node_ip_resolver -->|"queries DNS"| node_dns_services
node_ip_resolver -->|"tests latency"| node_https_targets
node_ip_resolver -->|"ranks answers"| node_ip_selector
node_ip_resolver -->|"writes mappings"| node_hosts_formatter
node_hosts_formatter -->|"writes"| node_hosts_file
node_hosts_formatter -->|"writes"| node_hosts_json
node_hosts_formatter -->|"updates"| node_readme_output
node_json_importer -->|"fetches"| node_remote_json
node_json_importer -->|"regenerates content"| node_hosts_formatter
node_hosts_file -->|"published as"| node_raw_hosts_service
node_hosts_json -->|"published as"| node_published_json
node_raw_hosts_service -->|"provides hosts"| node_host_tools
node_host_tools -->|"configures mappings"| node_user
node_user -->|"installs manually"| node_hosts_file

click node_ip_resolver "https://github.com/521xueweihan/github520/blob/main/fetch_ips.py"
click node_ip_selector "https://github.com/521xueweihan/github520/blob/main/fetch_ips.py"
click node_hosts_formatter "https://github.com/521xueweihan/github520/blob/main/common.py"
click node_json_importer "https://github.com/521xueweihan/github520/blob/main/update_ips.py"
click node_hosts_file "https://github.com/521xueweihan/github520/blob/main/hosts"
click node_hosts_json "https://github.com/521xueweihan/github520/blob/main/hosts.json"
click node_readme_output "https://github.com/521xueweihan/github520/blob/main/README.md"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_github_domains,node_dns_services,node_https_targets,node_ip_resolver,node_ip_selector,node_user toneBlue
class node_hosts_formatter,node_published_json,node_remote_json,node_json_importer,node_hosts_file,node_hosts_json,node_readme_output toneAmber
class node_host_tools,node_raw_hosts_service toneMint
```

## Components

### IP Discovery

- **GitHub Domains**
- **DNS Services**
- **HTTPS Targets**
- [Domain Resolver](https://github.com/521xueweihan/github520/blob/main/fetch_ips.py): `fetch_ips.py`
- [IP Selector](https://github.com/521xueweihan/github520/blob/main/fetch_ips.py): `fetch_ips.py`

### Content Generation

- [Hosts Formatter](https://github.com/521xueweihan/github520/blob/main/common.py): `common.py`
- **Published Hosts JSON**
- **Remote Hosts JSON**
- [JSON Importer](https://github.com/521xueweihan/github520/blob/main/update_ips.py): `update_ips.py`
- [hosts](https://github.com/521xueweihan/github520/blob/main/hosts): `hosts`
- [hosts.json](https://github.com/521xueweihan/github520/blob/main/hosts.json): `hosts.json`
- [README Output](https://github.com/521xueweihan/github520/blob/main/README.md): `README.md`

### Host Consumption

- **Host Tools**
- **Raw Hosts Service**

### Other components

- **User**

## Connections

- Domain Resolver → GitHub Domains: resolves (evidence: `fetch_ips.py`)
- Domain Resolver → DNS Services: queries DNS (evidence: `fetch_ips.py`)
- Domain Resolver → HTTPS Targets: tests latency (evidence: `fetch_ips.py`)
- Domain Resolver → IP Selector: ranks answers (evidence: `fetch_ips.py`)
- Domain Resolver → Hosts Formatter: writes mappings (evidence: `fetch_ips.py`)
- Hosts Formatter → hosts: writes (evidence: `common.py`)
- Hosts Formatter → hosts.json: writes (evidence: `common.py`)
- Hosts Formatter → README Output: updates (evidence: `common.py`)
- JSON Importer → Remote Hosts JSON: fetches (evidence: `update_ips.py`)
- JSON Importer → Hosts Formatter: regenerates content (evidence: `update_ips.py`)
- hosts → Raw Hosts Service: published as (evidence: `README.md`)
- hosts.json → Published Hosts JSON: published as (evidence: `README.md`)
- Raw Hosts Service → Host Tools: provides hosts (evidence: `README.md`)
- Host Tools → User: configures mappings (evidence: `README.md`)
- User → hosts: installs manually (evidence: `README.md`)