Refactored Firebase library

Firebase.cpp

@@ -15,114 +15,145 @@
 //
 #include "Firebase.h"
 
-const char* firebaseFingerprint = "7A 54 06 9B DC 7A 25 B3 86 8D 66 53 48 2C 0B 96 42 C7 B3 0A";
-const uint16_t firebasePort = 443;
+namespace {
+const char* kFirebaseFingerprint = "7A 54 06 9B DC 7A 25 B3 86 8D 66 53 48 2C 0B 96 42 C7 B3 0A";
+const uint16_t kFirebasePort = 443;
 
-Firebase::Firebase(const String& host) : _host(host) {
-  _http.setReuse(true);
+String makeFirebaseURL(const String& path, const String& auth) {
+  String url;
+  if (path[0] != '/') {
+    url = "/";
+  }
+  url += path + ".json";
+  if (auth.length() > 0) {
+    url += "?auth=" + auth;
+  }
+  return url;
+}
+
+}  // namespace
+
+Firebase::Firebase(const String& host) : host_(host) {
+  http_.setReuse(true);
 }
 
 Firebase& Firebase::auth(const String& auth) {
-  _auth = auth;
+  auth_ = auth;
   return *this;
 }
 
-String Firebase::get(const String& path) {
-  sendRequest("GET", path);
-  return readBody();
+FirebaseGet Firebase::get(const String& path) {
+  return FirebaseGet(host_, auth_, path, &http_);
 }
 
-String Firebase::push(const String& path, const String& value) {
-  sendRequest("POST", path, value);
-  return readBody();
+FirebasePush Firebase::push(const String& path, const String& value) {
+  return FirebasePush(host_, auth_, path, value, &http_);
 }
 
-void Firebase::remove(const String& path) {
-  sendRequest("DELETE", path);
+FirebaseRemove Firebase::remove(const String& path) {
+  return FirebaseRemove(host_, auth_, path, &http_);
 }
 
-String Firebase::set(const String& path, const String& value) {
-  sendRequest("PUT", path, value);
-  return readBody();
+FirebaseStream Firebase::stream(const String& path) {
+  // TODO: create new client dedicated to stream.
+  return FirebaseStream(host_, auth_, path, &http_);
 }
 
-Firebase& Firebase::stream(const String& path) {
-  _error.reset();
-  String url = makeURL(path); 
-  const char* headers[] = {"Location"};
-  _http.setReuse(true);  
-  _http.begin(_host.c_str(), firebasePort, url.c_str(), true, firebaseFingerprint);
-  _http.collectHeaders(headers, 1);
-  _http.addHeader("Accept", "text/event-stream");
-  int statusCode = _http.sendRequest("GET", (uint8_t*)NULL, 0);
-  String location;
-  // TODO(proppy): Add a max redirect check
-  while (statusCode == 307) {
-    location = _http.header("Location");
-    _http.setReuse(false);
-    _http.end();
-    _http.setReuse(true);    
-    _http.begin(location, firebaseFingerprint);
-    statusCode = _http.sendRequest("GET", (uint8_t*)NULL, 0);
+// FirebaseCall
+FirebaseCall::FirebaseCall(const String& host, const String& auth,
+			   const char* method, const String& path,
+			   const String& data, HTTPClient* http) : http_(http) {
+  String url = makeFirebaseURL(path, auth);
+  http_->setReuse(true);
+  http_->begin(host, kFirebasePort, url, true, kFirebaseFingerprint);
+
+  bool followRedirect = false;
+  if (method == "STREAM") {
+    method = "GET";
+    http_->addHeader("Accept", "text/event-stream");    
+    followRedirect = true;
   }
-  if (statusCode != 200) {
-    _error.set(statusCode,
-	       "stream " + location + ": "
-	       + HTTPClient::errorToString(statusCode));
+
+  if (followRedirect) {
+    const char* headers[] = {"Location"};
+    http_->collectHeaders(headers, 1);
   }
-  return *this;
-}
+
+  int status = http_->sendRequest(method, (uint8_t*)data.c_str(), data.length());
 
-String Firebase::makeURL(const String& path) {
-  String url;
-  if (path[0] != '/') {
-    url = "/";
+  // TODO: Add a max redirect check
+  if (followRedirect) {
+    while (status == HTTP_CODE_TEMPORARY_REDIRECT) {
+      String location = http_->header("Location");
+      http_->setReuse(false);
+      http_->end();
+      http_->setReuse(true);
+      http_->begin(location, kFirebaseFingerprint);
+      status = http_->sendRequest("GET", (uint8_t*)NULL, 0);
+    }
   }
-  url += path + ".json";
-  if (_auth.length() > 0) {
-    url += "?auth=" + _auth;
+
+  if (status != 200) {
+    error_ = FirebaseError(status, String(method) + " " + url + ": " + HTTPClient::errorToString(status));
+  }
+
+  // if not streaming.
+  if (!followRedirect) {
+    response_ = http_->getString();
   }
-  return url;
 }
 
-void Firebase::sendRequest(const char* method, const String& path, const String& value) {
-  String url = makeURL(path);
-  _http.begin(_host.c_str(), firebasePort, url.c_str(), true, firebaseFingerprint);
-  int statusCode =  _http.sendRequest(method, (uint8_t*)value.c_str(), value.length());
-  _error.reset();
-  if (statusCode < 0) {
-    _error.set(statusCode,
-               String(method) + " " + url + ": "
-               + HTTPClient::errorToString(statusCode));
-  }  
+// FirebaseGet
+FirebaseGet::FirebaseGet(const String& host, const String& auth,
+			 const String& path,
+			 HTTPClient* http)
+  : FirebaseCall(host, auth, "GET", path, "", http) {
+
+  if (!error()) {
+    // TODO: parse json
+    json_ = response();
+  }
 }
 
-String Firebase::readBody() {
-  if (_error.code() != 0) {
-    return "";
+// FirebasePush
+FirebasePush::FirebasePush(const String& host, const String& auth,
+			   const String& path, const String& value,
+			   HTTPClient* http)
+  : FirebaseCall(host, auth, "POST", path, value, http) {
+  if (!error()) {
+    // TODO: parse name
+    name_ = response();
   }
-  // no _http.end() because of connection reuse.
-  return _http.getString();
 }
 
-bool Firebase::connected() {
-  return _http.connected();
+// FirebasePush
+FirebaseRemove::FirebaseRemove(const String& host, const String& auth,
+			       const String& path,
+			       HTTPClient* http)
+  : FirebaseCall(host, auth, "DELETE", path, "", http) {
+}
+
+// FirebaseStream
+FirebaseStream::FirebaseStream(const String& host, const String& auth,
+			       const String& path,
+			       HTTPClient* http)
+  : FirebaseCall(host, auth, "STREAM", path, "", http) {
 }
 
-bool Firebase::available() {
-  return _http.getStreamPtr()->available();
+bool FirebaseStream::available() {
+  return http_->getStreamPtr()->available();
 }
 
-Firebase::Event Firebase::read(String& event) {
-  auto client = _http.getStreamPtr();
-  Event type;;
+FirebaseStream::Event FirebaseStream::read(String& event) {
+  auto client = http_->getStreamPtr();
+  Event type;
   String typeStr = client->readStringUntil('\n').substring(7);
   if (typeStr == "put") {
-    type = Firebase::Event::PUT;
+    type = Event::PUT;
   } else if (typeStr == "patch") {
-    type = Firebase::Event::PATCH;
+    type = Event::PATCH;
   } else {
-    type = Firebase::Event::UNKNOWN;
+    type = Event::UNKNOWN;
   }
   event = client->readStringUntil('\n').substring(6);
   client->readStringUntil('\n'); // consume separator

Firebase.h

@@ -25,56 +25,129 @@
 #include <WiFiClientSecure.h>
 #include <ESP8266HTTPClient.h>
 
-// FirebaseError represents a Firebase API error with a code and a
-// message.
+class FirebaseGet;
+class FirebasePush;
+class FirebaseRemove;
+class FirebaseStream;
+
+// Primary client to the Firebase backend.
+class Firebase {
+ public:
+  Firebase(const String& host);
+  Firebase& auth(const String& auth);
+
+  // Fetch result at "path".
+  FirebaseGet get(const String& path);
+
+  // Add new value to list at "path", will return key for the new item.
+  FirebasePush push(const String& path, const String& value);
+
+  // Deletes value at "path" from firebase.
+  FirebaseRemove remove(const String& path);
+
+  // Starts a stream of events that affect object at "path".
+  // TODO: fix FirebaseStream lifecycle
+  //       https://github.com/esp8266/Arduino/issues/500
+  FirebaseStream stream(const String& path);
+
+ private:
+  HTTPClient http_;
+  String host_;
+  String auth_;
+};
+
 class FirebaseError {
  public:
-  operator bool() const { return _code < 0; }
-  int code() const { return _code; }
-  const String& message() const { return _message; }
-  void reset() { set(0, ""); }
-  void set(int code, const String& message) {
-    _code = code;
-    _message = message;
+  FirebaseError() {}
+  FirebaseError(int code, const String& message) : code_(code), message_(message) {
+  }  
+  operator bool() const { return code_ != 0; }
+  int code() const { return code_; }
+  const String& message() const { return message_; }
+ private:  
+  int code_ = 0;
+  String message_ = "";
+};
+
+class FirebaseCall {
+ public:
+  FirebaseCall() {}
+  FirebaseCall(const String& host, const String& auth,
+	       const char* method, const String& path,
+	       const String& data = "",	       
+	       HTTPClient* http = NULL);
+  const FirebaseError& error() const {
+    return error_;
+  }
+  const String& response() {
+    return response_;
   }
+ protected:
+  HTTPClient* http_;
+  FirebaseError error_;
+  String response_;
+};
+
+class FirebaseGet : public FirebaseCall {
+ public:
+  FirebaseGet() {}
+  FirebaseGet(const String& host, const String& auth,
+	      const String& path, HTTPClient* http = NULL);
+
+  const String& json() const {
+    return json_;
+  }
+
  private:
-  int _code = 0;
-  String _message = "";
+  String json_;
 };
 
-// Firebase is the connection to firebase.
-class Firebase {
+class FirebasePush : public FirebaseCall {
  public:
-  Firebase(const String& host);
-  Firebase& auth(const String& auth);
-  const FirebaseError& error() const {
-    return _error;
+  FirebasePush() {}
+  FirebasePush(const String& host, const String& auth,
+	       const String& path, const String& value, HTTPClient* http = NULL);
+
+  const String& name() const {
+    return name_;
   }
-  String get(const String& path);
-  // write a new JSON `value` to the given `path`.
-  // Note: A String `value` must include double quotes to be valid json.
-  String set(const String& path, const String& value);
-  // append a new JSON `value` to the given `path`.
-  // Note: A String `value` must include double quotes to be valid json.
-  String push(const String& path, const String& value);
-  void remove(const String& path);
-  bool connected();
-  Firebase& stream(const String& path);
+
+ private:
+  String name_;
+};
+
+class FirebaseRemove : public FirebaseCall {
+ public:
+  FirebaseRemove() {}
+  FirebaseRemove(const String& host, const String& auth,
+		 const String& path, HTTPClient* http = NULL);
+};
+
+
+class FirebaseStream : public FirebaseCall {
+ public:
+  FirebaseStream() {}
+  FirebaseStream(const String& host, const String& auth,
+		 const String& path, HTTPClient* http = NULL);
+
+  // True if there is an event available.
   bool available();
+
+  // event type.
   enum Event {
     UNKNOWN,
     PUT,
     PATCH
   };
-  Event read(String& event);
- private:
-  String makeURL(const String& path);
-  void sendRequest(const char* method, const String& path, const String& value = "");
-  String readBody();
 
-  HTTPClient _http;
-  String _host;
-  String _auth;
+  // Read next event in stream.
+  Event read(String& event);  
+
+  const FirebaseError& error() const {
+    return _error;
+  }
+
+ private:
   FirebaseError _error;
 };