Merge pull request #136 from proppy/firebase-object

FirebaseObject: simplify API

Author: proppy

examples/FirebaseDemo_ESP8266/FirebaseDemo_ESP8266.ino

@@ -56,7 +56,7 @@ void loop() {
 
   // get value 
   Serial.print("number: ");
-  Serial.println((float)Firebase.get("number"));
+  Serial.println(Firebase.getFloat("number"));
   delay(1000);
 
   // remove value

examples/FirebaseRoom_ESP8266/FirebaseRoom_ESP8266.ino

@@ -20,24 +20,24 @@
 #include <ESP8266WiFi.h>
 #include <FirebaseArduino.h>
 
-const int pinGrove = 15;
-const int pinVibrator = 5;
-const int pinLightSensor = A0;
-const int pinLed = 12;
-const int pinButton = 14;
-const int pinFan = 13;
+const int grovePowerPin = 15;
+const int vibratorPin = 5;
+const int lightSensorPin = A0;
+const int ledPin = 12;
+const int buttonPin = 14;
+const int fanPin = 13;
 
 void setup() {
   Serial.begin(9600);
 
-  pinMode(pinGrove, OUTPUT);
-  digitalWrite(pinGrove, HIGH);
+  pinMode(grovePowerPin, OUTPUT);
+  digitalWrite(grovePowerPin, HIGH);
 
-  pinMode(pinVibrator, OUTPUT);
-  pinMode(pinLightSensor, INPUT);
-  pinMode(pinLed, OUTPUT);
-  pinMode(pinButton, INPUT);
-  pinMode(pinFan, OUTPUT);
+  pinMode(vibratorPin, OUTPUT);
+  pinMode(lightSensorPin, INPUT);
+  pinMode(ledPin, OUTPUT);
+  pinMode(buttonPin, INPUT);
+  pinMode(fanPin, OUTPUT);
 
   // connect to wifi.
   WiFi.begin("SSID", "PASSWORD");
@@ -62,15 +62,15 @@ int button = 0;
 float light = 0.0;
 
 void loop() {
-  digitalWrite(pinLed, (int)Firebase.get("redlight"));
-  digitalWrite(pinFan, (int)Firebase.get("cooldown"));
-  digitalWrite(pinVibrator, (int)Firebase.get("brrr"));
-  int newButton = digitalRead(pinButton);
+  digitalWrite(ledPin, Firebase.getInt("redlight"));
+  digitalWrite(fanPin, Firebase.getInt("cooldown"));
+  digitalWrite(vibratorPin, Firebase.getInt("brrr"));
+  int newButton = digitalRead(buttonPin);
   if (newButton != button) {
     button = newButton;
     Firebase.set("pushbutton", button);
   }
-  float newLight = analogRead(pinLightSensor);
+  float newLight = analogRead(lightSensorPin);
   if (abs(newLight - light) > 100) {
     light = newLight;
     Firebase.set("sunlight", light);

examples/FirebaseStream_ESP8266/FirebaseStream_ESP8266.ino

@@ -55,16 +55,16 @@ void loop() {
 
   if (Firebase.available()) {
      FirebaseObject event = Firebase.readEvent();
-     String event_type = event["type"];
-     event_type.toLowerCase();
+     String eventType = event.getString("type");
+     eventType.toLowerCase();
 
      Serial.print("event: ");
-     Serial.println(event_type);
-     if (event_type == "put") {
+     Serial.println(eventType);
+     if (eventType == "put") {
        Serial.print("data: ");
-       Serial.println(event["data"].asString());
-       String path = event["path"];
-       float data = event["data"];
+       Serial.println(event.getString("data"));
+       String path = event.getString("path");
+       float data = event.getFloat("data");
 
        display.clearDisplay();
        display.setTextSize(2);

src/FirebaseArduino.cpp

@@ -47,6 +47,43 @@ FirebaseObject FirebaseArduino::get(const char* path) {
   return FirebaseObject(get.response());
 }
 
+int FirebaseArduino::getInt(const char* path) {
+  auto get = FirebaseGet(host_, auth_, path, http_.get());
+  error_ = get.error();
+  if (failed()) {
+    return 0;
+  }
+  return FirebaseObject(get.response()).getInt();
+}
+
+
+float FirebaseArduino::getFloat(const char* path) {
+  auto get = FirebaseGet(host_, auth_, path, http_.get());
+  error_ = get.error();
+  if (failed()) {
+    return 0.0f;
+  }
+  return FirebaseObject(get.response()).getFloat();
+}
+
+String FirebaseArduino::getString(const char* path) {
+  auto get = FirebaseGet(host_, auth_, path, http_.get());
+  error_ = get.error();
+  if (failed()) {
+    return "";
+  }
+  return FirebaseObject(get.response()).getString();
+}
+
+bool FirebaseArduino::getBool(const char* path) {
+  auto get = FirebaseGet(host_, auth_, path, http_.get());
+  error_ = get.error();
+  if (failed()) {
+    return "";
+  }
+  return FirebaseObject(get.response()).getBool();
+}
+
 void FirebaseArduino::remove(const char* path) {
   auto remove = FirebaseRemove(host_, auth_, path, http_.get());
   error_ = remove.error();
@@ -67,7 +104,7 @@ FirebaseObject FirebaseArduino::readEvent() {
   String event = client->readStringUntil('\n').substring(6);
   client->readStringUntil('\n'); // consume separator
   FirebaseObject obj = FirebaseObject(event);
-  obj["type"] = type;
+  obj.getJsonVariant().asObject()["type"] = type;
   return obj;
 }
 

src/FirebaseArduino.h

@@ -58,11 +58,42 @@ class FirebaseArduino {
 
 
   /**
-   * Gets the value located at path.
+   * Gets the integer value located at path.
    * You should check success() after calling.
    * \param path The path to the node you wish to retrieve.
-   * \return The data located at that path. This may either be a single element
-   * or it may be a json structure. Will only be populated if success() is true.
+   * \return The integer value located at that path. Will only be populated if success() is true.
+   */
+  int getInt(const char* path);
+
+  /**
+   * Gets the float value located at path.
+   * You should check success() after calling.
+   * \param path The path to the node you wish to retrieve.
+   * \return The float value located at that path. Will only be populated if success() is true.
+   */
+  float getFloat(const char* path);
+
+  /**
+   * Gets the string value located at path.
+   * You should check success() after calling.
+   * \param path The path to the node you wish to retrieve.
+   * \return The string value located at that path. Will only be populated if success() is true.
+   */
+  String getString(const char* path);
+
+  /**
+   * Gets the boolean value located at path.
+   * You should check success() after calling.
+   * \param path The path to the node you wish to retrieve.
+   * \return The boolean value located at that path. Will only be populated if success() is true.
+   */
+  bool getBool(const char* path);
+
+  /**
+   * Gets the json object value located at path.
+   * You should check success() after calling.
+   * \param path The path to the node you wish to retrieve.
+   * \return a FirebaseObject value located at that path. Will only be populated if success() is true.
    */
   FirebaseObject get(const char* path);
 
@@ -94,7 +125,7 @@ class FirebaseArduino {
   /**
    * Reads the next event in a stream. This is only meaningful once stream() has
    * been called.
-   * \return Object will have ["type"] that describes the event type, ["path"]
+   * \return FirebaseObject will have ["type"] that describes the event type, ["path"]
    * that describes the effected path and ["data"] that was updated.
    */
   FirebaseObject readEvent();

src/FirebaseObject.cpp

@@ -16,57 +16,81 @@
 
 #include "FirebaseObject.h"
 
-namespace {
-template<typename T>
-T decodeJsonLiteral(const String& json) {
-  return JsonVariant{ArduinoJson::RawJson{json.c_str()}};
-}
-
-// ugly workaround to https://github.com/bblanchon/ArduinoJson/issues/265
-template<>
-String decodeJsonLiteral<String>(const String& json) {
-  StaticJsonBuffer<JSON_ARRAY_SIZE(1)> buf;
-  String array = "[" + json + "]";
-  return buf.parseArray(&array[0])[0];
-}
-}  // namespace
-
 FirebaseObject::FirebaseObject(const String& data) : data_{data} {
-  if (data_[0] == '{') {
-    json_ = &buffer_.parseObject(&data_[0]);
-  } else if (data_[0] == '"') {
-    data_ = decodeJsonLiteral<String>(data_);
-  }
+  json_ = buffer_.parse(&data_[0]);
+  // TODO(proppy): find a way to check decoding error, tricky because
+  // ArduinoJson doesn't surface error for variant parsing.
+  // See: https://github.com/bblanchon/ArduinoJson/issues/279
 }
 
-FirebaseObject::operator bool() {
-  return decodeJsonLiteral<bool>(data_);
+bool FirebaseObject::getBool(const String& path) {
+  JsonVariant variant = getJsonVariant(path);
+  if (!variant.is<bool>()) {
+    error_ = "failed to convert to bool";
+    return 0;
+  }
+  return static_cast<bool>(variant);
 }
 
-FirebaseObject::operator int() {
-    return decodeJsonLiteral<int>(data_);
+int FirebaseObject::getInt(const String& path) {
+  JsonVariant variant = getJsonVariant(path);
+  if (!variant.is<int>()) {
+    error_ = "failed to convert to int";
+    return 0;
+  }
+  return static_cast<int>(variant);
 }
 
-FirebaseObject::operator float() {
-    return decodeJsonLiteral<float>(data_);
+float FirebaseObject::getFloat(const String& path) {
+  JsonVariant variant = getJsonVariant(path);
+  if (!variant.is<float>()) {
+    error_ = "failed to convert to float";
+    return 0;
+  }
+  return static_cast<float>(variant);
 }
 
-FirebaseObject::operator const String&() {
-    return data_;
+String FirebaseObject::getString(const String& path) {
+  JsonVariant variant = getJsonVariant(path);
+  if (!variant.is<const char *>()) {
+    error_ = "failed to convert to string";
+    return "";
+  }
+  return static_cast<const char*>(variant);
 }
 
-FirebaseObject::operator const JsonObject&() {
-  return *json_;
+JsonVariant FirebaseObject::getJsonVariant(const String& path) {
+  String key(path);
+  char* start = &key[0];
+  char* end = start + key.length();
+  // skip first `/`.
+  if (*start == '/') {
+    start++;
+  }
+  JsonVariant json = json_;
+  while (start < end) {
+    // TODO(proppy) split in a separate function.
+    char* p = start;
+    // advance to next `/`.
+    while (*p && (*p != '/')) p++;
+    // make `start` a C string.
+    *p = 0;
+    // return json variant at `start`.
+    json = json.asObject().get(start);
+    // advance to next path element.
+    start = p + 1;
+  }
+  return json;
 }
 
-JsonObjectSubscript<const char*> FirebaseObject::operator[](const char* key) {
-    return json_->operator[](key);
+bool FirebaseObject::failed() const {
+  return error_.length() > 0;
 }
 
-JsonObjectSubscript<const String&> FirebaseObject::operator[](const String& key) {
-  return json_->operator[](key);
+bool FirebaseObject::success() const {
+  return error_.length() == 0;
 }
 
-JsonVariant FirebaseObject::operator[](JsonObjectKey key) const {
-  return json_->operator[](key);
+const String& FirebaseObject::error() const {
+  return error_;
 }