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Elf

Elf is an HTTP server which lets you interact with it through a command-line interface. It gives you a quick and easy interface to set up routes and attach actions to them.

Elf provides a large collection of built-in actions, which can be added and configured with a fair amount of ease, from the command-line interface. And all of these can be achieved without writing a bit of code. The elf was primarily created for the purpose of quickly mocking HTTP based services without using going through the hassle of installing another scripting language.

Elf is a single executable that you can download and put in your path, to get started right away. Elf attempts to make it trivially easy to setup HTTP endpoints. The elf CLI provides a bash like command-line editing interface and intelligent TAB completions, that lets you manage routes and actions with ease.

NOTE: Elf is an experiment and is expected to be used for testing purposes only. Elf is not intended for production usage.

Install

$ go get github.com/agupta666/elf

Quickstart

To start elf, fire the below command in a terminal. This starts Elf in interactive mode and drops you to a prompt. Now you are ready to interact with the HTTP server listening on port 8080.

$ elf
starting default http endpoint 0.0.0.0:8080
elf>  

Hitting the TAB key will display a list of commands supported by Elf. See the command reference section for details of the individual commands.

Routes and Actions

Elf lets you set up routes using the route command, which is of the form

elf> route </some/path> <action>

Thus when a request is received that matches the given path, elf executes the action attached to it.

For example, the below route command will attach a built-in action [which will respond with the contents of the data.txt file] for a request matching the given path.

elf> route /data @data.txt

Thus sending a HTTP request using curl, displays the response shown below.

$ curl -i http://localhost:8080/data
HTTP/1.1 200 OK
Content-Type: text/plain; charset=utf-8
Date: Mon, 04 Sep 2017 18:40:49 GMT
Transfer-Encoding: chunked

contents of data.txt ...

Built-in actions

Action Reference

File

This is a built-in action that serves a static file. A static file can be specified with its absolute path with @ as a prefix.

E.g.:

route /static @/var/www/index.html

Shell Commands

This is a builtin action which executes the specified command on the local server and responds with the output. This action can be specified by prefixing ! before the shell command

Examples

elf> route /clip !pbpaste

elf> route /go !"w3m -dump https://golang.org/doc/effective_go.html"

Generate arbitrary data

elf> route /download "data[9024,.bin]"
elf> route /download "data[9024,.bin,trivia]"

Generate Images

route /some/route "image[width, height, color, format, name]"

elf> route /download "image[400,400]"
elf> route /download "image[400,400, #E32171]"
elf> route /download "image[400,400, #E32171, .png]"
elf> route /download "image[400,400, #E32171, .png, gopher]"

Respond with the JSON representation of a Key-Value set

Create a new Key-Value set

elf> kvset dset a:1 b:2 c:3

now add a route with a JSON action

elf> route /api json[dset]

Upload files

add a route with upload action

elf> route /save "upload[/path/to/some/folder, picture]"

upload file with curl

$ curl --form picture=@somefile.png http://localhost:8080/save