Update examples/src/main.cpp

examples/src/main.cpp

@@ -0,0 +1,86 @@
+#include <Arduino.h>
+#include <WiFi.h>
+#include <ArduinoJson.h>  // Include ArduinoJson library
+#include <HTTPClient.h>
+
+const char* ssid = "OSULL";
+const char* password = "thisispassword";
+const char* APIKey = "f4b7aff25779483bba8cac91900f6efc";
+// Use HTTP instead of HTTPS for a bit more simplicity
+String serverName = "http://lapi.transitchicago.com/api/1.0/ttpositions.aspx";
+
+
+// Last run time for the loop, don't need to query too often, stored in milliseconds
+unsigned long lastTime = 0;
+// How often to update table (every 60 seconds)
+// unsigned long queryTime = 60*1000
+unsigned long queryTime = 5*1000;
+
+// Let's just look at Rosemont for now
+unsigned int station_num = 40820;
+unsigned int station_eta = 999;
+
+void setup() {
+  Serial.begin(115200);
+  WiFi.begin(ssid, password);
+  
+  while (WiFi.status() != WL_CONNECTED) {
+    delay(1000);
+    Serial.print("Connecting to WiFi... SSID:");
+    Serial.print(ssid);
+    Serial.println("...");
+  }
+  
+  Serial.println("Connected to WiFi!");
+  Serial.print("IP Address: ");
+  Serial.println(WiFi.localIP());
+}
+
+void loop() {
+  // Only run if we haven't run in queryTime
+  if ((millis() - lastTime) > queryTime) {
+    // Query the HTTP endpoint with a POST request and parameters, only interested in Blue route for now
+    const char* route = "Blue";
+    
+    // http object let's us query a webserver
+    HTTPClient http;
+
+    String serverPath = serverName + "?key=" + APIKey + "&rt=" + route + "&outputType=JSON";
+    http.useHTTP10(true);
+    http.begin(serverPath.c_str());
+    int httpResponse = http.GET();
+    
+
+    // Minimum size acquired from pasting raw JSON into here: https://arduinojson.org/v5/assistant/
+    DynamicJsonDocument location_json(9128);
+    deserializeJson(location_json, http.getStream()); 
+
+    // Store time we queried server
+    const char* time = location_json["ctatt"]["tmst"];
+
+    Serial.print("Time of query: ");
+    Serial.println(time);
+
+    const char* nextStaID = location_json["ctatt"]["route"][0]["train"][0]["nextStaID"];
+    Serial.println(nextStaID);
+
+    // Move through the array to find 
+    for (JsonObject train : location_json["ctatt"]["route"][0]["train"].as<JsonArray>()) {
+      const char* nextSta = train["nextStaId"]; 
+      unsigned int arrSta = train["arrT"]; 
+
+      String output = String("Next train arriving at ") + nextSta + " at time " + arrSta;
+      Serial.println(output);
+
+      // Only care about one station for now
+      if(arrSta == station_num) {
+        // Found Rosemont
+        // Calculate time difference
+        time_t arrSta_t = arrSta
+        // TODO
+      }
+    }
+
+    lastTime = millis();
+  }
+}