Add new example

examples/Space_Station/ISS_API_Class.cpp

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+// Space Station class functions which supports the main sketch
+
+#include "ISS_API_Class.h" // Include the header with the function prototypes etc
+
+/***************************************************************************************
+**  Connect to website and get the International Space Station pass times
+***************************************************************************************/
+void SpaceStation::getPasses(String latitude, String longitude, ISS_pass* passData)
+{
+  this->passData = passData; // Make a copy of the pointer for this class
+
+  JsonStreamingParser json;      // Create an instance of the parser
+  json.setListener(this); // Pass pointer to "this" SpaceStation class to the listener
+                          // so it can call the support functions in this class
+
+  // Use WiFiClient class to create TCP connections
+  WiFiClient client;
+
+  // URL and port of the server
+  const char*  host = "api.open-notify.org";
+  const int httpPort = 80;
+
+  // Connect as a client to the server
+  if (!client.connect(host, httpPort)) {
+    Serial.println("connection failed");
+    return;
+  }
+
+  // Built up the GET request
+  String url = "http://api.open-notify.org/iss-pass.json?lat=" + latitude + "&lon=" + longitude + "&n=" + PASSES;
+
+  // Send GET request
+  Serial.println("\nSending GET request to api.open-notify.org...\n");
+  client.print(String("GET ") + url + " HTTP/1.1\r\n" + "Host: " + host + "\r\n" + "Connection: close\r\n\r\n");
+
+  // Local variables for time-out etc
+  uint32_t timeout = millis();
+  char c = 0;
+  uint16_t ccount = 0;
+
+  Serial.println("=====>   Header start   <=====");
+
+  // Read the header that precedes the JSON, ends with \r\n
+  while ( client.available() > 0 || client.connected())
+  {
+    String line = client.readStringUntil('\n');
+    if (line == "\r") {
+      Serial.println("=====>   Header end    <=====");
+      break;
+    }
+
+    Serial.println(line); // Print the header to serial monitor for viewing
+
+    // Check for timeout
+    if ((millis() - timeout) > 5000UL)
+    {
+      Serial.println ("HTTP header timeout");
+      client.stop();
+      return;
+    }
+  }
+
+  // The JSON message should now be in the buffer for reading
+
+  // Read the JSON character by character and pass it to the JSON decoder
+  // The decoder will call the SpaceStation class  during decoding, so we can
+  // save the decoded values
+
+  // Use OR since data may still be in the buffer when the client has disconnected!
+  while ( client.available() > 0 || client.connected())
+  {
+    while(client.available() > 0)
+    {
+      c = client.read(); // Read a received character
+
+      #ifdef SHOW_JSON   // Optionally show the message with a simple formatter
+      Serial.print(c);
+      #endif
+
+      json.parse(c);     // Pass to the parser, parser will call listener support functions as needed
+
+      // Check for timeout
+      if ((millis() - timeout) > 8000UL)
+      {
+        Serial.println ("JSON parse client timeout");
+        json.reset();
+        client.stop();
+        return;
+      }
+      yield();
+    }
+  }
+
+  json.reset();
+
+  client.stop();
+
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a key has been read
+***************************************************************************************/
+void SpaceStation::key(String key) {
+  currentKey = key;
+
+  //Serial.print("key: ");
+  //Serial.println(key);
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a value has been read
+***************************************************************************************/
+void SpaceStation::value(String val) {
+
+  // Test only:
+  //Serial.print("\nvaluePath     :"); Serial.println(valuePath);
+  //Serial.print("currentParent :"); Serial.println(currentParent);
+  //Serial.print("currentKey    :"); Serial.println(currentKey);
+  //Serial.print("arrayIndex    :"); Serial.println(arrayIndex);
+  //Serial.print("Value    :"); Serial.println(val);
+
+  if (currentParent == "")
+  {
+    if (currentKey == "message") passData->message = val;
+    return;
+  }
+
+  else
+  if (currentParent == "request")
+  {
+    if (currentKey == "datetime") passData->datetime = (uint32_t)val.toInt();
+  }
+
+  else
+  if (valuePath == "/response")
+  {
+    if (currentKey == "duration") passData->passDuration[arrayIndex] = (uint16_t)val.toInt();
+    else
+    if (currentKey == "risetime") passData->passRiseTime[arrayIndex] = (uint32_t)val.toInt();
+  }
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a start of document decoded
+***************************************************************************************/
+void SpaceStation::startDocument() {
+  currentParent = currentKey = "";
+  arrayIndex = 0;
+  ended = false;
+
+  //Serial.println("\nstart document");
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a end of document decoded
+***************************************************************************************/
+void SpaceStation::endDocument() {
+  ended = true;
+
+  //Serial.println("end document. ");
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a start of object decoded
+***************************************************************************************/
+void SpaceStation::startObject() {
+  currentParent = currentKey;
+
+  //Serial.println("start object. ");
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a end of object decoded
+***************************************************************************************/
+void SpaceStation::endObject() {
+  currentParent = "";
+  arrayIndex++;
+
+  //Serial.println("end object. ");
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when an array of values has started
+***************************************************************************************/
+void SpaceStation::startArray() {
+   arrayIndex  = 0;
+   valuePath = currentParent + "/" + currentKey;
+
+   //Serial.println("start array. ");
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when an array of values has ended
+***************************************************************************************/
+void SpaceStation::endArray() {
+  valuePath = "";
+
+  //Serial.println("end array. ");
+}
+
+/***************************************************************************************
+**  JSON Decoder library calls this when a character is whitespace (not used here)
+***************************************************************************************/
+void SpaceStation::whitespace(char c) {
+
+  //Serial.println("whitespace");
+}

examples/Space_Station/ISS_API_Class.h

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+// Header for Space Station class which supports the main sketch
+#pragma once
+
+#define SHOW_JSON  // Print the JSON to the serial monitor
+#define PASSES 7   // Number of ISS passes to fetch
+
+// Choose the WiFi library to load
+#ifdef ESP8266
+  #include <ESP8266WiFi.h> // Built in library for ESP8266
+#else // ESP32
+  #include <WiFi.h>        // Built in library for ESP32
+#endif
+
+#include <WiFiUdp.h>       // Built in library
+
+#include "JsonStreamingParser.h"
+#include "JsonListener.h"
+
+// Structure to hold the parsed values
+typedef struct ISS_pass {
+  String    message;       // Message, usually "sucess"
+  uint32_t  datetime = 0;  // Time of request, UTC unix time in seconds since Jan 01 1970
+  uint16_t  passDuration[PASSES] = { 0 }; // Pass duration in seconds
+  uint32_t  passRiseTime[PASSES] = { 0 }; // Time of pass, UTC unix time
+} ISS_pass;
+
+class SpaceStation: public JsonListener {
+
+  public:
+
+    void getPasses(String latitude, String longitude, ISS_pass* passData);
+
+    // Start of Listener support functions
+
+    void key(String key);
+
+    void value(String value);
+
+    void startDocument();
+
+    void endDocument();
+
+    void startObject();
+
+    void endObject();
+
+    void startArray();
+
+    void endArray();
+
+    void whitespace(char c);
+
+    // End of Listener support functions
+
+  private:
+
+    bool     ended = true;  // Flag to indicate document has ended
+
+    String   currentParent; // Current object e.g. "request"
+
+    String   currentKey;    // Name key of the name:value pair e.g "temperature"
+
+    uint16_t arrayIndex;    // Array index 0-N e.g. 4 for 5th pass, qualify with valuePath
+
+    String   valuePath;     // object (i.e. sequential key) path (like a "file path")
+                            // taken to the name:value pair in the form "/response"
+                            // so values can be pulled from the correct array.
+                            // Needed since different objects contain "data" arrays.
+
+    ISS_pass *passData;     // pointer provided by sketch
+};