# eolas-api

API written in NodeJS that queries my Zettelkasten, Eolas.

It is a constituent part of my knowledge management system comprising [eolas](https://forgejo.systemsobscure.net/thomasabishop/eolas),
[eolas-db](https://forgejo.systemsobscure.net/thomasabishop/eolas-db), and [eolas-app](https://forgejo.systemsobscure.net/thomasabishop/eolas-app).

The application reads from an SQLite database managed via [eolas-db](https://forgejo.systemsobscure.net/thomasabishop/eolas-db).

## Local development

```sh
npm install
npm run start
```

This will start the local server at `http://localhost:4000`. It will look for
stub database at `/data/eolas.db`.

## Deployment

The API is deployed to my remote VPS, residing at `/var/www/eolas-api`. The
database that it reads from is located at `/data/sqlite/eolas/eolas.db`.

Deployment is automated via [Forgejo action](https://forgejo.systemsobscure.net/thomasabishop/eolas-api/src/branch/main/.forgejo/workflows/deploy.yaml). Deployment actions are always executed by the `deploy` user on the VPS.

The action script transfers the source files to the VPS and installs necessary
packages. It also restarts the `eolas-api` systemd service on the VPS.

### `systemd` service

On the VPS, `eolas-api` runs as a `systemd` service. See the
[unit file](./systemd/eolas-api.service) for details.

## API

### Entries

#### Get all entries

Return all entries. Optionally limit by length and/or date.

```
GET /entries?limit=2&sort=date
```

```json
{
  "count": 5,
  "data": [
    {
      "title": "SSH",
      "last_modified": "2025-07-10 14:26:04"
    },
    {
      "title": "List_largest_files_bash",
      "last_modified": "2025-07-07 16:49:12"
    }
  ]
}
```

#### Get specific entry

```
GET /entries/Memory_versus_processor
```

```json
{
  "title": "Memory_versus_processor",
  "last_modified": "2024-10-18 19:17:01",
  "size": 270,
  "body": "# Memory versus processor\n\n Would a more powerful processor with average or reduced memory capacity..."
}
```

#### Get backlinks for an entry

Defaults to alphabetic list.

```
GET /entries/backlinks/The_kernel
```

```json
{
  "count": 3,
  "data": ["Boot_process", "Containerization", "CPU_architecture"]
}
```

#### Get outlinks for an entry

Defaults to alphabetic list.

```
GET /entries/outlinks/The_kernel
```

```json
{
  "count": 3,
  "data": ["Basic_model_of_the_operating_system", "Processes", "User_Space"]
}
```

#### Get entries associated with a specified tag

Optionally sort chronologically.

```
GET /entries/tag/memory?sort=date
```

```json
{
  "count": 3,
  "data": [
    {
      "entry_title": "Memory_addresses"
    },
    {
      "entry_title": "Call_stack"
    },
    {
      "entry_title": "The_memory_hierarchy"
    }
  ]
}
```

### Tags

#### Get all tags

Sorted alphabetically.

```
GET /tags
```

```json
{
  "count": 119,
  "data": ["algebra", "algorithms", "analogue", "android", "..."]
}
```

#### Get tags for specified entry

```
GET /tags/The_kernel
```

```json
{
  "count": 4,
  "data": [
    "computer-architecture",
    "memory",
    "operating-systems",
    "systems-programming"
  ]
}
```