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# like them? see https://unsplash.com/collections/94734566/slidev
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# some information about your slides (markdown enabled)
title: Datastar
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class: text-center
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---

# To The Stars with Datastar

An interstellar journey



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<h2 v-click class="absolute top-4 left-1/2 -translate-x-1/2">Drake Formular</h2>

<div class="mt-20">

$$ {1|2|3|4|5|6|7|all}
\begin{aligned}
N &= R_* \cdot f_p \cdot n_e \cdot f_l \cdot f_i \cdot f_c \cdot L \\
R_* &= \text{rate of star formation} \\
f_p &= \text{fraction of stars with planets} \\
n_e &= \text{number of habitable planets per star} \\
f_l &= \text{fraction where life develops} \\
f_i &= \text{fraction where intelligent life evolves} \\
f_c &= \text{fraction that develops detectable technology} \\
L &= \text{length of time civilizations are detectable}
\end{aligned}
$$

</div>

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<h2 v-click class="absolute top-4 left-1/2 -translate-x-1/2">The "Drake" Formular of Webtechnologies</h2>

<div class="mt-20">

$$ {1|all}
\begin{aligned}
N_w &= D_b \cdot L_b \cdot F_b \cdot P_t \cdot F_f \cdot S_m \cdot C_{ss} \cdot C_l \cdot H_p  \\
\\
N_w &= \text{Total Possible Tech Stacks} \\
D_b &= \text{databases (PostgreSQL, MongoDB, MySQL...)} \\
L_b &= \text{backend languages (Javascript, Python, Go...)} \\
F_b &= \text{backend frameworks (Express, Django, FastAPI...)} \\
P_t &= \text{transport protocols (REST, GraphQL, gRPC...)} \\
F_f &= \text{frontend frameworks (React, Vue, Svelte...)} \\
S_m &= \text{state management (Redux, Zustand, Pinia...)} \\
C_{ss} &= \text{CSS frameworks (Tailwind, UnoCSS, Bootstrap...)} \\
C_l &= \text{component libraries (shadcn, MUI, Ant Design...)} \\
H_p &= \text{hosting platforms (Vercel, AWS, VPS...)} \\
\end{aligned}
$$

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<h2 class="absolute top-4 left-1/2 -translate-x-1/2">The Space of Webtechnologies</h2>

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$$ 
\begin{aligned}
N_w &= ( D_b ,  L_b , F_b , P_t , F_f , S_m , C_{ss} , C_l , H_p )  \\
\\
\end{aligned}
$$

- Every website or web application is one star in this space.
- There are many combinations that work well. While others no so much.
- We all plot our path in this space. And have our current home there.
- There are clusters in this space, i.e. the React-Cluster, oder Angular or Vue.
- My current home is in the L-O-B with Go and Vue vicinity.
- There is an old Cluster called Hypermedia. Where all Webapps once lived. 
- Hypermedia has developed a new bulge called HTMX.
- Next to it is a new tiny blob, called Datastar.



</div>

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# My name is 
# Thomas Hedeler

# A holistic developer

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# How did I find Datastar? What is my motivation?

### Finding my combination of web technologies for a minimal viable web application.

<div class="mt-10"/>

- Part 1: The Database: SQLite
- Part 2: The No-ORM ORM - A very simple Data Abstraction Layer.
- Part 3: Developing a Web Server Application in Go.
- Part 4: Datastar - a lightweight framework for real-time collaborative web apps.
- Part 5: Modern HTML and modern CSS.
- Part 6: Web components.
- Part 7: Simple Deployments with a VPS, Nginx, Certbot and a single binary file.

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# Part 1: SQLite:
### It is fast, feature complete* and rock solid.
<div class="mt-10"/>

## It is not SQ-Lite, it is SQL-ite



Since everybody knows SQLite, today just a few highlights:

- It has JSON and JSONB as built-in data types.
- It has 29 new functions to extract from JSON or to create JSON objects.
- It's CTEs make SQL Turing complete.
- The SQLite CLI can be used to execute "SQL-scripts". See demo.

<div class="mt-40"/>

<div> * from my pov and for my needs and purposes</div>
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# Part 2: A very simple Data Abstraction Layer:

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Features:
- Simplified Database Lifecycle Management.
- Generic Data Handling.
- High-Level CRUD Operations.
- Fluent Transaction API.
- Abstraction and Safety.
- Utility Functions.

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# Part 3: Developing a Web Server Application in Go.

<div class="mt-10"/>

Why Go?

- Go is a compiled language that generates native machine code.
- Go's core strength is its built-in, lightweight concurrency model using goroutines and channels.
- Go has a small, well-defined specification and a deliberately simple syntax.
- The standard library is comprehensive, especially for web development.
- Go compiles into a single, static binary with no external dependencies.
- Go is simple, just 25 reserved words in the language.
- Can embed the database engine (modernc/sqlite)
- Can serve static code from embeded folders and files.
- Can embed other resources, like sql files or template files.
- Has a built-in templating engine.
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# Part 4: Datastar

<div class="mt-10"/>

Quote Gillian Delany: 

> The problem is Datastar is actually a backend agnostic backend framework with a 10 Kb shim. There has never been anything like it in practice. So it is hard to explain.



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# Term-Soup:
<div class="mt-10"/>

ADR, core+plugins, Signals, Ideomorph, Core-Engine, Plug-ins, SSE, 
You have to control the backend, Templating, HTMX, Hypermedia, Hateoas, 
Locality of behaviour, 
Declarative vs. Imperative, DS conforms strictly to the web's specs.

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# Reducing the Network to a Function Call

```js
{
    const { data, error } = await to(fetch("https://api.example.com/api/board"));
    if (error) {
      // handle error
      return;
    }
    // handle data
}
{
    const { data, error } = await to(fetch("https://api.example.com/api/users/12"));
    if (error) {
      // handle error
      return;
    }
    // handle data
}

// the function that "unwraps" the promise:
export function to(promise: Promise<Response>) {
  return promise
    .then((response) => response.json())
    .then((data) => ({ data, error: null }))
    .catch((error) => ({ data: null, error }));
}

```
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# HTTP - Protocol
#  

<div><span v-mark.circle.purple="5">POST</span> https://api.example.com<span v-mark.circle.orange="1">/api/users/search</span>?<span v-mark.circle.red="2">page=2&limit=10</span> HTTP/1.1</div>
<div v-mark.box.blue="3">
<div>Host: api.example.com</div>
<div>User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64)</div>
<div>Accept: application/json</div>
<div>Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9</div>
<div>Cookie: sessionId=abc123; theme=dark</div>
<div>Content-Length: 89</div>
</div>

<div mt-4 ></div>
<div  v-mark.box.green="4">
<div>{</div>
<div>body: data for the search request</div>
<div>}</div>
</div>

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# SSE - Server-Sent Events
#

<div><span v-mark.circle.purple="5">GET</span> https://api.example.com<span v-mark.circle.orange="1">/api/events/stream</span> HTTP/1.1</div>
<div v-mark.box.blue="2">
<div>Host: api.example.com</div>
<div>Accept: text/event-stream</div>
<div>Cache-Control: no-cache</div>
<div>Connection: keep-alive</div>
</div>

<div mt-4></div>
<div text-sm op-70>Response:</div>
<div v-mark.box.green="3">
<div>HTTP/1.1 200 OK</div>
<div>Content-Type: text/event-stream</div>
<div>Cache-Control: no-cache</div>
<div>Connection: keep-alive</div>
</div>

<div mt-4></div>
<div v-mark.box.yellow="4">
<div>event: message</div>
<div>data: {"user": "Alice", "action": "joined"}</div>
<div></div>
<div>event: update</div>
<div>data: {"count": 42}</div>
<div></div>
<div>data: Multi-line</div>
<div>data: message example</div>
<div></div>
</div>


---
layout: two-cols
layoutClass: gap-16
---
# HTTP Communication
#
```mermaid  { scale: 0.6}
sequenceDiagram
    participant Browser
    participant Backend
    
    Note over Browser,Backend: Traditional HTTP (Polling)
    Browser->>Backend: GET /api/data
    Backend-->>Browser: Response with data
    Note over Browser: Wait...
    Browser->>Backend: GET /api/data
    Backend-->>Browser: Response with data
    Note over Browser: Wait...
    Browser->>Backend: GET /api/data
    Backend-->>Browser: Response with data
```
::right::
# SSE Communication
#
```mermaid  { scale: 0.6}
sequenceDiagram
    participant Browser
    participant Backend
    
    Note over Browser,Backend: Server-Sent Events (SSE)
    Browser->>Backend: GET /api/events (Accept: text/event-stream)
    Backend-->>Browser: 200 OK (Connection open)
    Note over Backend,Browser: Connection stays open
    Backend-->>Browser: event: updatedata: {...}
    Backend-->>Browser: event: updatedata: {...}
    Backend-->>Browser: event: updatedata: {...}
    Note over Browser,Backend: Real-time updates without new requests
```
---
layout: two-cols
layoutClass: gap-2
---

```mermaid  { scale: 0.4}
graph TD
    Start([Client Starts]) --> GetProducts[GET /products]
    
    GetProducts --> ProductResp["Response: Product List<br/>links:<br/>add-to-cart: /cart/items<br/>self: /products"]
    
    ProductResp --> AddCart[POST /cart/items]
    
    AddCart --> CartResp["Response: Cart Updated<br/>links:<br/>self: /cart<br/>update-item: /cart/items/id<br/>remove-item: /cart/items/id<br/>checkout: /checkout"]
    
    CartResp --> Decision1{Client Action}
    Decision1 -->|Continue Shopping| GetProducts
    Decision1 -->|Proceed| Checkout[POST /checkout]
    
    Checkout --> CheckoutResp["Response: Checkout Session<br/>links:<br/>payment: /payment<br/>cancel: /cart"]

    
```
::right::
```mermaid  { scale: 0.4}
graph TD
    CheckoutResp["Response: Checkout Session<br/>links:<br/>payment: /payment<br/>cancel: /cart"] --> Payment[POST /payment]
    
    Payment --> PaymentResp["Response: Payment Success<br/>links:<br/>order: /orders/id<br/>track: /orders/id/tracking<br/>invoice: /orders/id/invoice"]
    
    PaymentResp --> GetOrder[GET /orders/id]
    
    GetOrder --> OrderState{Order State}
    
    OrderState -->|Pending| PendingResp["Response: Order Pending<br/>links:<br/>self: /orders/id<br/>cancel: /orders/id/cancel<br/>track: /orders/id/tracking"]
    
    OrderState -->|Shipped| ShippedResp["Response: Order Shipped<br/>links:<br/>self: /orders/id<br/>track: /orders/id/tracking<br/>return: /orders/id/return"]
    
    OrderState -->|Delivered| DeliveredResp["Response: Order Delivered<br/>links:<br/>self: /orders/id<br/>return: /orders/id/return<br/>review: /orders/id/review"]
    
    PendingResp --> End([Workflow Complete])
    ShippedResp --> End
    DeliveredResp --> End

    
```

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# Learn Some Templating System:
<div class="mt-10"/>

| Concept           | Example                                  | Meaning                    |
| ----------------- | ---------------------------------------- | -------------------------- |
| **Interpolation** | `{{ name }}`                             | Insert value of `name`     |
| **Loop**          | `{% for item in items %}...{% endfor %}` | Repeat block for each item |
| **Condition**     | `{% if logged_in %}Welcome{% endif %}`   | Conditional rendering      |
| **Include**       | `{% include 'header.html' %}`            | Reuse a subtemplate        |
| **Escaping**      | `{{{ raw_html }}}` or `{{& raw_html}}`   | Control HTML escaping      |


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# Templating and Hypermedia:
<div class="mt-10"/>

|   | Templating               | Hypermedia as the Engine of Application State |
| --------- | ------------------------ | ------------------------------------------ |
| Input     | Data                     | Data + available transitions               |
| Output    | Document (HTML)          | Document representing a state with actions |
| Function  | Bind data to structure   | Bind state transitions to structure        |
| Goal      | Present information      | Drive navigation and state evolution       |
| Mechanism | Placeholder substitution | Link/form embedding                        |
| Example   | `{{.Title}}` → “Article” | `<a href="{{.Links.Edit}}">Edit</a>`       |


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# to be continued ...