httpoison on Poeticoding

Elixir Stream and large HTTP responses: processing text

Wed, 03 Apr 2019 16:02:19 +0000

Part 1 - Elixir Stream to process large HTTP responses on the fly
Part 2 - this article

You find the code, of this and the previous article, on poeticoding/httpstream_articles GitHub repo. The code at this repo is not meant for production use, is just part of the examples of these articles.

Elixir Streams to process large HTTP responses on the fly

Wed, 27 Mar 2019 16:48:21 +0000

Part 1 - this article
Part 2 - Elixir Stream and large HTTP responses: processing text

This is the first of a two-part article where we see a handy way of handling async HTTP responses.\

In this first part we see how make an Elixir Stream out of a large HTTP response.
In the second part we will extend the implementation so we can download a large text file, processing lines on the fly.

First and foremost … WHY?

Why should we handle HTTP responses with Streams, when we can just simply use something like HTTPoison.get to receive a response with the data we need?

The Primitives of Elixir Concurrency: a Full Example

Tue, 19 Mar 2019 15:39:08 +0000

Previous articles about Concurrency in Elixir:\

Let’s put in practice what we’ve seen in the last few articles about concurrency. In this article we see how to fully make our initial cryptocurrency example, using just HTTPoison module and spawn, send and receive to handle concurrency. At the end we will refactor it using Task, which makes everything far easier!

Download Large Files with HTTPoison Async Requests

Wed, 13 Feb 2019 16:37:55 +0000

With HTTPoison is really easy to do HTTP requests in Elixir. If we need to get the latest BTC-USD exchange rate from the Coinbase API, we just use the HTTPoison.get! passing the url and query parameters.

iex> url = "https://api.coinbase.com/v2/prices/spot"
iex> resp = HTTPoison.get!(url, %{}, params: [currency: "USD"])

%HTTPoison.Response{
 body: "{\"data\":{\"amount\":\"3585.005\" ... }}",
 ...
 status_code: 200
} 

iex> %{"data" => %{"amount" => amount}} = Jason.decode!(resp.body)
iex> String.to_float(amount)
3585.005

We easily get the response with a JSON body containing the information we need. We then use a library like Jason to de-serialise the JSON string and then get the amount using pattern matching.