# Downstream
[](https://travis-ci.org/mpiercy827/downstream)
[](https://hex.pm/packages/downstream/)
Downstream is a library for downloading files via HTTPoison response streaming.
## Installation
To use Downstream in your project, include it in your `mix.exs` file dependencies
and applications:
```elixir
def application do
[applications: [:downstream]]
end
def deps do
[
{:downstream, "~> 1.0.0"}
]
end
```
## Usage
Using `Downstream` is simple. First, start it your application:
```elixir
Downstream.start()
```
Then, just pass it a URL and an IO device:
```elixir
iex(1)> file = File.open!("index.html", [:write])
#PID<0.84.0>
iex(2)> Downstream.get("https://www.google.com", file)
{:ok,
%Downstream.Response{
device: #PID<0.84.0>,
headers: [
{"Date", "Sat, 09 Feb 2019 14:25:34 GMT"},
{"Expires", "-1"},
{"Cache-Control", "private, max-age=0"},
{"Content-Type", "text/html; charset=ISO-8859-1"},
...
{"Server", "gws"},
{"X-XSS-Protection", "1; mode=block"},
{"X-Frame-Options", "SAMEORIGIN"},
{"Accept-Ranges", "none"},
{"Vary", "Accept-Encoding"},
{"Transfer-Encoding", "chunked"}
],
status_code: 200
}}
iex(3)> File.close(file)
:ok
```
Bang methods are also provided:
```elixir
iex(1)> file = File.open!("index.html", [:write])
#PID<0.84.0>
iex(2)> Downstream.get("https://www.google.com", file)
%Downstream.Response{
device: #PID<0.84.0>,
headers: [
{"Date", "Sat, 09 Feb 2019 14:25:34 GMT"},
{"Expires", "-1"},
{"Cache-Control", "private, max-age=0"},
{"Content-Type", "text/html; charset=ISO-8859-1"},
...
{"Server", "gws"},
{"X-XSS-Protection", "1; mode=block"},
{"X-Frame-Options", "SAMEORIGIN"},
{"Accept-Ranges", "none"},
{"Vary", "Accept-Encoding"},
{"Transfer-Encoding", "chunked"}
],
status_code: 200
}}
iex(3)> File.close(file)
:ok
```
`Downstream` currently supports streaming downloads via the `get/2`, `post/2`, `get!/2` and `post!/2` methods. For all non-200 status codes, an error is returned.
```elixir
iex(1)> file = File.open!("index.html", [:write])
#PID<0.84.0>
iex(2)> Downstream.get("https://www.google.com/notfound", file)
{:error,
%Downstream.Error{
device: #PID<0.84.0>,
reason: :invalid_status_code,
status_code: 404
}}
iex(3)> File.close(file)
:ok
```
## Current Features
- Stream downloads via HTTP GET requests
- Stream downloads via HTTP POST requests
- Configurable request timeouts
## Development
### Running Tests
To run the tests, run one of the following commands:
```bash
$ mix test # Run test suite without code coverage analysis
$ mix coveralls.html # Run test suite with code coverage analysis
```
### Linter
To run the linter, run the following command:
```bash
$ mix credo
```
### Type Analysis
To run a static type analysis with Dialyzer, run the following command:
```bash
$ mix dialyzer
```
### Formatting
This project uses the default configuration for the Elixir formatter. To format
any changes, run the following command:
```bash
$ mix format
```
