Merge pull request #104 from koic/add-ruby-weather-server

Add Ruby weather server example

Author: jonathanhefner

.gitignore

@@ -10,6 +10,9 @@ dist/
 wheels/
 *.egg-info
 
+# Bundler-generated files
+Gemfile.lock
+
 # Virtual environments
 .venv
 

weather-server-ruby/Gemfile

@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gem "mcp"

weather-server-ruby/README.md

@@ -0,0 +1,3 @@
+# A Simple MCP Weather Server written in Ruby
+
+See the [Quickstart](https://modelcontextprotocol.io/quickstart) tutorial for more information.

weather-server-ruby/weather.rb

@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+require "json"
+require "mcp"
+require "net/http"
+require "uri"
+
+NWS_API_BASE = "https://api.weather.gov"
+USER_AGENT = "weather-app/1.0"
+
+module HelperMethods
+  def make_nws_request(url)
+    uri = URI(url)
+    request = Net::HTTP::Get.new(uri)
+    request["User-Agent"] = USER_AGENT
+    request["Accept"] = "application/geo+json"
+
+    response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
+      http.request(request)
+    end
+
+    raise "HTTP #{response.code}: #{response.message}" unless response.is_a?(Net::HTTPSuccess)
+
+    JSON.parse(response.body)
+  end
+
+  def format_alert(feature)
+    properties = feature["properties"]
+
+    <<~ALERT
+      Event: #{properties["event"] || "Unknown"}
+      Area: #{properties["areaDesc"] || "Unknown"}
+      Severity: #{properties["severity"] || "Unknown"}
+      Description: #{properties["description"] || "No description available"}
+      Instructions: #{properties["instruction"] || "No specific instructions provided"}
+    ALERT
+  end
+end
+
+class GetAlerts < MCP::Tool
+  extend HelperMethods
+
+  tool_name "get_alerts"
+  description "Get weather alerts for a US state"
+  input_schema(
+    properties: {
+      state: {
+        type: "string",
+        description: "Two-letter US state code (e.g. CA, NY)"
+      }
+    },
+    required: ["state"]
+  )
+
+  def self.call(state:)
+    url = "#{NWS_API_BASE}/alerts/active/area/#{state.upcase}"
+    data = make_nws_request(url)
+
+    if data["features"].empty?
+      return MCP::Tool::Response.new([{
+        type: "text",
+        text: "No active alerts for this state."
+      }])
+    end
+
+    alerts = data["features"].map { |feature| format_alert(feature) }
+    MCP::Tool::Response.new([{
+      type: "text",
+      text: alerts.join("\n---\n")
+    }])
+  end
+end
+
+class GetForecast < MCP::Tool
+  extend HelperMethods
+
+  tool_name "get_forecast"
+  description "Get weather forecast for a location"
+  input_schema(
+    properties: {
+      latitude: {
+        type: "number",
+        description: "Latitude of the location"
+      },
+      longitude: {
+        type: "number",
+        description: "Longitude of the location"
+      }
+    },
+    required: ["latitude", "longitude"]
+  )
+
+  def self.call(latitude:, longitude:)
+    # First get the forecast grid endpoint.
+    points_url = "#{NWS_API_BASE}/points/#{latitude},#{longitude}"
+    points_data = make_nws_request(points_url)
+
+    # Get the forecast URL from the points response.
+    forecast_url = points_data["properties"]["forecast"]
+    forecast_data = make_nws_request(forecast_url)
+
+    # Format the periods into a readable forecast.
+    periods = forecast_data["properties"]["periods"]
+    forecasts = periods.first(5).map do |period|
+      <<~FORECAST
+        #{period["name"]}:
+        Temperature: #{period["temperature"]}°#{period["temperatureUnit"]}
+        Wind: #{period["windSpeed"]} #{period["windDirection"]}
+        Forecast: #{period["detailedForecast"]}
+      FORECAST
+    end
+
+    MCP::Tool::Response.new([{
+      type: "text",
+      text: forecasts.join("\n---\n")
+    }])
+  end
+end
+
+server = MCP::Server.new(
+  name: "weather",
+  version: "1.0.0",
+  tools: [GetAlerts, GetForecast]
+)
+
+transport = MCP::Server::Transports::StdioTransport.new(server)
+transport.open