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# Ivar
Ivar is an adapter based HTTP client that provides the ability to build composable HTTP requests.
The key goals of Ivar are to allow requests to be constructed in a composable manner (pipeline friendly) and to simplify building, sending and receiving requests for a number of well known
http clients.
## Supported Adapters
| HTTP Client | Adapter |
| ----------- | ------- |
| HTTPoison | [ivar_httpoison](https://github.com/swelham/ivar_httpoison) |
## Usage
Add `ivar` to your list of dependencies in `mix.exs`, plus the http adapter you are going to use:
```elixir
def deps do
[
{:ivar, "~> 0.9.0"},
{:ivar_httpoison, "~> 0.1.0"}
]
end
```
Setup up the config for your chosen adapater
```elixir
config :ivar,
adapter: Ivar.HTTPoison
```
### Basic usage
```elixir
Ivar.get("https://example.com")
|> Ivar.send
|> Ivar.unpack
# {"<!doctype html>\n<html>...", %HTTPoison.Response{}}
```
### JSON encoding/decoding
Ivar uses the `Poison` library for encoding and decoding JSON, so make sure you
have it listed along side Ivar in your `mix.exs`.
```elixir
def deps do
[
{:ivar, "~> 0.9.0"},
{:poison, "~> 3.0"},
...
]
end
```
You can then specify that you want to send JSON when putting the request body. If
the response contains the `application/json` content type header, the `Ivar.unpack`
function will then decode the response for you.
```elixir
Ivar.post("https://some-echo-server")
|> Ivar.put_body(%{some: "data"}, :json)
|> Ivar.send
|> Ivar.unpack
# {%{some: "data"}, %HTTPoison.Response{}}
```
### Real world example
This is simplified extract from a real world application where Ivar is being used to
send email via the mailgun service.
```elixir
url = "https://api.mailgun.net/v3/domain.com/messages"
mail_data = %{to: "someone@example.com", ...}
files = [{"inline", File.read!("elixir.png"), "elixir.png"}, ...]
Ivar.new(:post, url)
|> Ivar.put_auth({"api", "mailgun_api_key"}, :basic)
|> Ivar.put_body(mail_data, :url_encoded)
|> Ivar.put_files(files)
|> Ivar.send
```