From 0d4ada6c102ad775e11f33694487173cddce03bc Mon Sep 17 00:00:00 2001
From: href <href@random.sh>
Date: Sun, 11 Dec 2022 00:26:59 +0000
Subject: couch: improve, add post, put

---
 lib/couch.ex | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 86 insertions(+), 10 deletions(-)

(limited to 'lib/couch.ex')

diff --git a/lib/couch.ex b/lib/couch.ex
index fdd8579..2d75314 100644
--- a/lib/couch.ex
+++ b/lib/couch.ex
@@ -1,18 +1,94 @@
 defmodule Couch do
-  def get(db, doc) do
-    config = Application.get_env(:lsg, :couch)
-    url = [Keyword.get(config, :url), db, doc] |> Enum.join("/")
-    user = Keyword.get(config, :user)
-    pass = Keyword.get(config, :pass)
-    client_options = Keyword.get(config, :client_options, [])
-    headers = [{"accept", "application/json"}, {"user-agent", "beautte"}]
-    options = [hackney: [:insecure, {:basic_auth, {user, pass}}]] ++ client_options
+  @moduledoc """
+  Simple, no-frills, CouchDB client
+  """
+
+  @type base_error :: {:error, :bad_request} | {:error, :unauthorized} |
+                      {:error, :server_error} | {:error, :service_unavailable} |
+                      {:error, :bad_response} | {:error, HTTPoison.Error.t()}
+
+  def new(db, params \\ []) do
+    {url, headers, options} = prepare_request([db], [], params)
+    case HTTPoison.put(url, headers, options) do
+      {:ok, %HTTPoison.Response{status_code: ok, body: body}} when ok in [201, 202] ->
+        :ok
+      {:ok, %HTTPoison.Response{status_code: 412}} ->
+        {:error, :exists}
+      error ->
+        handle_generic_response(error)
+    end
+  end
+
+  @doc """
+  Retrieve a document `doc` from `db`.
+
+  `params` are [documented here](https://docs.couchdb.org/en/3.2.2-docs/api/document/common.html)
+  """
+  @spec get(String.t(), String.t(), Keyword.t()) :: {:ok, Map.t()} | {:error, :not_found} | {:error, any()}
+  def get(db, doc, params \\ []) do
+    {url, headers, options} = prepare_request([db, doc], [], params)
     case HTTPoison.get(url, headers, options) do
       {:ok, %HTTPoison.Response{status_code: 200, body: body}} ->
         {:ok, Poison.decode!(body)}
-      {:ok, %HTTPoison.Response{status_code: 404}} ->
-        {:error, :not_found}
       error -> {:error, {:couchdb_error, error}}
     end
   end
+
+  @spec post(String.t(), Map.t(), Keyword.t()) :: {:error, :operation_failed} | {:error, :not_found} | {:error, :exists} | {:error, any()}
+  def post(db, data, params \\ []) do
+    {url, headers, options} = prepare_request([db], [{"content-type", "application/json"}], params)
+    with \
+      {:ok, %HTTPoison.Response{status_code: ok, body: body}} when ok in [201, 202] <- HTTPoison.post(url, Poison.encode!(data), headers, options),
+      {:json, {:ok, %{"ok" => true, "id" => id, "rev" => rev}}} <- {:json, Poison.decode(body)} do
+        {:ok, id, rev}
+    else
+      {:ok, %HTTPoison.Response{status_code: 409}} -> {:error, :exists}
+      {:json, {:ok, body}} ->
+        Logger.error("couch: operation failed: #{inspect body}")
+        {:error, :operation_failed}
+       error -> handle_generic_response(error)
+    end
+  end
+
+  @spec put(String.t(), Map.t(), Keyword.t()) :: {:error, :operation_failed} | {:error, :not_found} | {:error, :conflict} | {:error, any()}
+  def put(db, doc = %{"_id" => id, "_rev" => _}, params \\ []) do
+    {url, headers, options} = prepare_request([db, id], [{"content-type", "application/json"}], params)
+    case HTTPoison.put(url, Poison.encode!(doc), headers, options) do
+      {:ok, %HTTPoison.Response{status_code: ok, body: body}} when ok in [201, 202] ->
+        body = Poison.decode!(body)
+        if Map.get(body, "ok") do
+          {:ok, Map.get(body, "id"), Map.get(body, "rev")}
+        else
+          {:error, :operation_failed}
+        end
+      {:ok, %HTTPoison.Response{status_code: 209}} ->
+        {:error, :conflict}
+      error -> handle_generic_response(error)
+    end
+  end
+
+  defp prepare_request(path, headers \\ [], params \\ [], options \\ []) do
+    config = Application.get_env(:lsg, :couch)
+
+    base_url = Keyword.get(config, :url, "http://localhost:5984")
+    url = URI.merge(base_url, Path.join(path)) |> to_string()
+
+    headers = headers ++ [{"accept", "application/json"}, {"user-agent", "beautte"}]
+
+    params = Enum.map(params, fn({k, v}) -> {to_string(k), v} end)
+    client_options = Keyword.get(config, :client_options, [])
+    options = [params: params] ++ options ++ client_options
+
+    user = Keyword.get(config, :user)
+    pass = Keyword.get(config, :pass)
+    hackney_options = Keyword.get(options, :hackney, [])
+    hackney_options = if user, do: [{:basic_auth, {user, pass}} | hackney_options], else: []
+    options = [{:hackney, [:insecure | hackney_options]} | options]
+
+    {url, headers, options}
+  end
+
+  defp handle_generic_response(%HTTPoison.Response{status_code: code}), do: {:error, Plug.Conn.Status.reason_atom(code)}
+  defp handle_generic_response(%HTTPoison.Error{reason: reason}), do: {:error, reason}
+
 end
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