Merge pull request #75 from chrisccerami/latest_photos

Add latest_photos endpoint

README.md

@@ -56,6 +56,12 @@ https://api.nasa.gov/mars-photos/api/v1/rovers/curiosity/photos?sol=1000&camera=
 
 https://api.nasa.gov/mars-photos/api/v1/rovers/opportunity/photos?earth_date=2015-6-3&camera=pancam
 
+#### Query For Latest Photos
+
+If you just want to receive photo data for the most recent Sol for which photos exist for a particular rover, you can visit the `/latest_photos` endpoint.
+
+https://api.nasa.gov/mars-photos/api/v1/rovers/curiosity/latest_photos
+
 ### Mission Manifest Endpoint
 
 A mission manifest is available for each Rover at the `/manifests/<rover_name>`. This manifest will list details of the Rover's mission to help narrow down photo queries to the API. The information in the manifest includes:

app/controllers/api/v1/latest_photos_controller.rb

@@ -0,0 +1,26 @@
+class Api::V1::LatestPhotosController < ApplicationController
+  def index
+    def index
+      @rover = Rover.find_by name: params[:rover_id].titleize
+      if @rover
+        render json: search_photos
+      else
+        render json: { errors: "Invalid Rover Name" }, status: :bad_request
+      end
+    end
+  end
+
+  private
+
+  def photo_params
+    params.permit(:camera, :earth_date).merge(sol: @rover.photos.maximum(:sol))
+  end
+
+  def search_photos
+    photos = @rover.photos.order(:camera_id, :id).search photo_params, @rover
+    if params[:page]
+      photos = photos.page(params[:page]).per params[:per_page]
+    end
+    photos
+  end
+end

config/routes.rb

@@ -7,6 +7,7 @@
     namespace :v1 do
       resources :rovers, only: [:show, :index] do
         resources :photos, only: :index
+        resources :latest_photos, only: :index
       end
       resources :photos, only: :show
       resources :manifests, only: :show