# Kapow!

## Why?

Because we think that:

- UNIX is great and we love it
- The UNIX shell is great
- HTTP interfaces are convenient and everywhere
- CGI is not a good way to mix them


## How?

So, how we can mix the **web** and the **shell**? Let's see...

The **web** and the **shell** are two different beasts, both packed with
history.

There are some concepts in HTTP and the shell that **resemble each other**.

```
                 +------------------------+-------------------------+
                 | HTTP                   | SHELL                   |
  +--------------+------------------------+-------------------------+
  | Input        | POST form-encoding     | Command line parameters |
  | Parameters   | GET parameters         | Environment variables   |
  |              | Headers                |                         |
  |              | Serialized body (JSON) |                         |
  +--------------+------------------------+-------------------------+
  | Data Streams | Response/Request Body  | Stdin/Stdout/Stderr     |
  |              | Websocket              | Input/Output files      |
  |              | Uploaded files         |                         |
  +--------------+------------------------+-------------------------+
  | Control      | Status codes           | Signals                 |
  |              | HTTP Methods           | Exit Codes              |
  +--------------+------------------------+-------------------------+
```

Any tool designed to give an HTTP interface to an existing shell command
**must map concepts of boths**. For example:

- "GET parameters" to "Command line parameters"
- "Headers" to "Environment variables"
- "Stdout" to "Response body"

Kapow! is not opinionated about the different ways you can map both worlds.
Instead it provides a concise set of tools used to express the mapping and a
set of common defaults.


### Why not tool "X"?

All the alternatives we found are **rigid** about how they match between HTTP
and shell concepts.

* [shell2http](https://github.com/msoap/shell2http): HTTP-server to execute
  shell commands. Designed for development, prototyping or remote control.
Settings through two command line arguments, path and shell command.
* [websocketd](https://github.com/joewalnes/websocketd): Turn any program that
  uses STDIN/STDOUT into a WebSocket server. Like inetd, but for WebSockets.
* [webhook](https://github.com/adnanh/webhook): webhook is a lightweight
  incoming webhook server to run shell commands.
* [gotty](https://github.com/yudai/gotty): GoTTY is a simple command line tool
  that turns your CLI tools into web applications. (For interactive commands
only)
* [shell-microservice-exposer](https://github.com/jaimevalero/shell-microservice-exposer):
  Expose your own scripts as a cool microservice API dockerizing it.

Tools with a rigid matching **can't evade** *[impedance
mismatch](https://haacked.com/archive/2004/06/15/impedance-mismatch.aspx/)*.
Resulting in an easy-to-use software, convenient in some scenarios but
incapable in others.


### Why not my good-old programming language "X"?

* Boilerplate
* Custom code = More bugs
* Security issues (Command injection, etc)
* Dependency on developers
* **"A programming language is low level when its programs require attention to
  the irrelevant"** *Alan Perlis*
* **There is more Unix-nature in one line of shell script than there is in ten
  thousand lines of C** *Master Foo*


### Why not CGI?

TODO: Small explanation and example.


## What?

We named it Kapow!. It is pronounceable, short and meaningless... like every
good UNIX command ;-)

TODO: Definition
TODO: Intro to Architecture


# HTTP API

Kapow! server interacts with the outside world only through its HTTP API. Any
program making the correct HTTP request to a Kapow! server, can change its
behavior.

### Servers

TODO: Define servers' API

### Routes

Routes are the mechanism that allows Kapow! to find the correct program to
respond to an external event (e.g. an incomming HTTP request).

#### List of current routes
##### URL
##### Method
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

#### Append a new route
##### URL
##### Method
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

#### Insert a route
##### URL
##### Method
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

#### Delete a route
##### URL
##### Method
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

### Handlers

#### Get the value for a handler key
##### URL
##### Method
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

#### Overwrite the value for a handler key
##### URL
##### Method
POST
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

#### Append to the value for a handler key
##### URL
##### Method
PUT
##### URL Params
##### Data Params
##### Success Response
##### Error Response
##### Sample Call
##### Notes

## Spec'ing the endpoints

## Usage Example

## Test Suite Notes

The test suite is located on [blebleble] directory.
You can run it...


# Framework
## Commands
Any compliant implementation of Kapow! must provide these commands:

### `kapow`
This implements the server, yaddayadda

#### Example

### `kroute`
TODISCUSS: maybe consider using `kapow route` instead

#### Example

### `request`

#### Example

### `response`

#### Example

## Full-fledged example  (TODO: express it more simply)


## Test Suite Notes

# Server


## Test Suite Notes