WiFi: improve WiFiClient(Basic) examples (#5197)

WiFiClient no longer depends on now-defunct data.sparkfun.com
service, but uses a TCP "quote of the day" service instead.

fixes #4088

Author: yoursunny

libraries/ESP8266WiFi/examples/WiFiClient/WiFiClient.ino

@@ -1,19 +1,15 @@
 /*
-    This sketch sends data via HTTP GET requests to data.sparkfun.com service.
-
-    You need to get streamId and privateKey at data.sparkfun.com and paste them
-    below. Or just customize this script to talk to other HTTP servers.
-
+    This sketch establishes a TCP connection to a "quote of the day" service.
+    It sends a "hello" message, and then prints received data.
 */
 
 #include <ESP8266WiFi.h>
 
 const char* ssid     = "your-ssid";
 const char* password = "your-password";
 
-const char* host = "data.sparkfun.com";
-const char* streamId   = "....................";
-const char* privateKey = "....................";
+const char* host = "djxmmx.net";
+const uint16_t port = 17;
 
 void setup() {
   Serial.begin(115200);
@@ -43,54 +39,44 @@ void setup() {
   Serial.println(WiFi.localIP());
 }
 
-int value = 0;
-
 void loop() {
-  delay(5000);
-  ++value;
-
   Serial.print("connecting to ");
-  Serial.println(host);
+  Serial.print(host);
+  Serial.print(':');
+  Serial.println(port);
 
   // Use WiFiClient class to create TCP connections
   WiFiClient client;
-  const int httpPort = 80;
-  if (!client.connect(host, httpPort)) {
+  if (!client.connect(host, port)) {
     Serial.println("connection failed");
+    delay(5000);
     return;
   }
 
-  // We now create a URI for the request
-  String url = "/input/";
-  url += streamId;
-  url += "?private_key=";
-  url += privateKey;
-  url += "&value=";
-  url += value;
-
-  Serial.print("Requesting URL: ");
-  Serial.println(url);
-
-  // This will send the request to the server
-  client.print(String("GET ") + url + " HTTP/1.1\r\n" +
-               "Host: " + host + "\r\n" +
-               "Connection: close\r\n\r\n");
+  // This will send a string to the server
+  Serial.println("sending data to server");
+  client.println("hello from ESP8266");
   unsigned long timeout = millis();
   while (client.available() == 0) {
     if (millis() - timeout > 5000) {
       Serial.println(">>> Client Timeout !");
       client.stop();
+      delay(60000);
       return;
     }
   }
 
   // Read all the lines of the reply from server and print them to Serial
-  while (client.available() || client.connected()) {
-    String line = client.readStringUntil('\r');
-    Serial.print(line);
+  Serial.println("receiving from remote server");
+  while (client.available()) {
+    char ch = static_cast<char>(client.read());
+    Serial.print(ch);
   }
 
+  // Close the connection
   Serial.println();
   Serial.println("closing connection");
-}
+  client.stop();
 
+  delay(300000); // execute once every 5 minutes, don't flood remote service
+}

libraries/ESP8266WiFi/examples/WiFiClientBasic/WiFiClientBasic.ino

@@ -1,11 +1,18 @@
 /*
-    This sketch sends a message to a TCP server
-
+    This sketch sends a string to a TCP server, and prints a one-line response.
+    You must run a TCP server in your local network.
+    For example, on Linux you can use this command: nc -v -l 3000
 */
 
 #include <ESP8266WiFi.h>
 #include <ESP8266WiFiMulti.h>
 
+const char* ssid     = "your-ssid";
+const char* password = "your-password";
+
+const char* host = "192.168.1.1";
+const uint16_t port = 3000;
+
 ESP8266WiFiMulti WiFiMulti;
 
 void setup() {
@@ -14,7 +21,7 @@ void setup() {
 
   // We start by connecting to a WiFi network
   WiFi.mode(WIFI_STA);
-  WiFiMulti.addAP("SSID", "passpasspass");
+  WiFiMulti.addAP(ssid, password);
 
   Serial.println();
   Serial.println();
@@ -35,13 +42,10 @@ void setup() {
 
 
 void loop() {
-  const uint16_t port = 80;
-  const char * host = "192.168.1.1"; // ip or dns
-
-
-
   Serial.print("connecting to ");
-  Serial.println(host);
+  Serial.print(host);
+  Serial.print(':');
+  Serial.println(port);
 
   // Use WiFiClient class to create TCP connections
   WiFiClient client;
@@ -54,9 +58,10 @@ void loop() {
   }
 
   // This will send the request to the server
-  client.println("Send this data to server");
+  client.println("hello from ESP8266");
 
   //read back one line from server
+  Serial.println("receiving from remote server");
   String line = client.readStringUntil('\r');
   Serial.println(line);