Moved begin to into own method to have that logic in a single place.

InfluxDb.cpp

@@ -23,10 +23,7 @@ Influxdb::Influxdb(String host, uint16_t port) {
  */
 void Influxdb::setDb(String db) {
   _db = String(db);
-  // TODO: recreate client on db change
-  // http = new HTTPClient();
-  http.begin(_host, _port, "/write?db=" + _db);
-  http.addHeader("Content-Type", "text/plain");
+  begin();
 }
 
 /**
@@ -36,11 +33,19 @@ void Influxdb::setDbAuth(String db, String user, String pass) {
   _db = String(db);
   _user = user;
   _pass = pass;
-  // TODO: recreate client on db change
-  // http = new HTTPClient();
-  http.begin(_host, _port, "/write?u=" + _user + "&p=" + _pass + "&db=" + _db );
+  begin();
+}
+
+void Influxdb::begin() {
+  // TODO: recreate HttpClient on db change?
+  if (_user && _pass) {
+    http.begin(_host, _port, "/write?u=" + _user + "&p=" + _pass + "&db=" + _db);
+  } else {
+    http.begin(_host, _port, "/write?db=" + _db);
+  }
   http.addHeader("Content-Type", "text/plain");
 }
+
 /**
  * Prepare a measurement to be sent.
  */
@@ -71,11 +76,11 @@ boolean Influxdb::write(InfluxData data) { return write(data.toString()); }
  * for a list of error codes.
  */
 boolean Influxdb::write(String data) {
-  Serial.print(" -> writing to " + _db + ":\n");
+  Serial.print(" --> writing to " + _db + ":\n");
   Serial.println(data);
 
   int httpResponseCode = http.POST(data);
-  Serial.print(" <- Response: ");
+  Serial.print(" <-- Response: ");
   Serial.print(httpResponseCode);
 
   String response = http.getString();

InfluxDb.h

@@ -17,7 +17,6 @@ class Influxdb {
   Influxdb(String host, uint16_t port = 8086);
 
   void setDb(String db);
-
   void setDbAuth(String db, String user, String pass);
 
   void prepare(InfluxData data);
@@ -34,4 +33,6 @@ class Influxdb {
   String _user;
   String _pass;
   std::list<InfluxData> prepared;
+
+  void begin();
 };

README.md

@@ -11,15 +11,15 @@ Library for NodeMcu / ESP8266 (and Arduino?) for sending measurements to an Infl
  #define INFLUXDB_USER "user"
  #define INFLUXDB_PASS "password"
 
- // TODO: connect to WiFi
+ // connect to WiFi
 
  Influxdb influx(INFLUXDB_HOST); // port defaults to 8086
- // or
+ // or to use a custom port
  Influxdb influx(INFLUXDB_HOST, INFLUXDB_PORT);
 
  // set the target database
  influx.setDb(INFLUXDB_DATABASE);
- // or 
+ // or use a db with auth
  influx.setDbAuth(INFLUXDB_DATABASE, INFLUXDB_USER, INFLUXDB_PASS) // with authentication
 ```