ff32b50499
Add a weather server example using the MCP Ruby SDK and the National Weather Service API, following the same pattern as other language examples. https://github.com/modelcontextprotocol/ruby-sdk
127 lines
3.2 KiB
Ruby
127 lines
3.2 KiB
Ruby
# frozen_string_literal: true
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require "json"
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require "mcp"
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require "net/http"
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require "uri"
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NWS_API_BASE = "https://api.weather.gov"
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USER_AGENT = "weather-app/1.0"
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module HelperMethods
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def make_nws_request(url)
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uri = URI(url)
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request = Net::HTTP::Get.new(uri)
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request["User-Agent"] = USER_AGENT
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request["Accept"] = "application/geo+json"
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response = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) do |http|
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http.request(request)
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end
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raise "HTTP #{response.code}: #{response.message}" unless response.is_a?(Net::HTTPSuccess)
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JSON.parse(response.body)
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end
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def format_alert(feature)
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properties = feature["properties"]
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<<~ALERT
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Event: #{properties["event"] || "Unknown"}
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Area: #{properties["areaDesc"] || "Unknown"}
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Severity: #{properties["severity"] || "Unknown"}
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Description: #{properties["description"] || "No description available"}
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Instructions: #{properties["instruction"] || "No specific instructions provided"}
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ALERT
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end
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end
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class GetAlerts < MCP::Tool
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extend HelperMethods
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tool_name "get_alerts"
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description "Get weather alerts for a US state"
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input_schema(
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properties: {
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state: {
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type: "string",
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description: "Two-letter US state code (e.g. CA, NY)"
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}
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},
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required: ["state"]
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)
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def self.call(state:)
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url = "#{NWS_API_BASE}/alerts/active/area/#{state.upcase}"
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data = make_nws_request(url)
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if data["features"].empty?
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return MCP::Tool::Response.new([{
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type: "text",
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text: "No active alerts for this state."
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}])
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end
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alerts = data["features"].map { |feature| format_alert(feature) }
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MCP::Tool::Response.new([{
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type: "text",
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text: alerts.join("\n---\n")
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}])
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end
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end
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class GetForecast < MCP::Tool
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extend HelperMethods
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tool_name "get_forecast"
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description "Get weather forecast for a location"
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input_schema(
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properties: {
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latitude: {
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type: "number",
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description: "Latitude of the location"
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},
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longitude: {
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type: "number",
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description: "Longitude of the location"
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}
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},
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required: ["latitude", "longitude"]
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)
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def self.call(latitude:, longitude:)
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# First get the forecast grid endpoint.
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points_url = "#{NWS_API_BASE}/points/#{latitude},#{longitude}"
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points_data = make_nws_request(points_url)
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# Get the forecast URL from the points response.
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forecast_url = points_data["properties"]["forecast"]
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forecast_data = make_nws_request(forecast_url)
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# Format the periods into a readable forecast.
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periods = forecast_data["properties"]["periods"]
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forecasts = periods.first(5).map do |period|
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<<~FORECAST
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#{period["name"]}:
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Temperature: #{period["temperature"]}°#{period["temperatureUnit"]}
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Wind: #{period["windSpeed"]} #{period["windDirection"]}
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Forecast: #{period["detailedForecast"]}
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FORECAST
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end
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MCP::Tool::Response.new([{
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type: "text",
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text: forecasts.join("\n---\n")
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}])
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end
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end
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server = MCP::Server.new(
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name: "weather",
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version: "1.0.0",
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tools: [GetAlerts, GetForecast]
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)
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transport = MCP::Server::Transports::StdioTransport.new(server)
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transport.open
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