Attempt to read Flask event-stream on ESP8266

stream_receiver.ino

#include <ESP8266WiFi.h>
#include <String.h>
const char* ssid     = "guest";
const char* password = "superSecret";

const char* host = "192.168.2.150";
const char* streamId   = "....................";
const char* privateKey = "....................";

//
// LCD
//

#include <Wire.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_GFX.h>

// OLED display TWI address
#define OLED_ADDR   0x3C

Adafruit_SSD1306 display(-1);

#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif

//
//  ===========
//  START SETUP
//  ===========
//

void setup() {
  Serial.begin(115200);
  delay(10);

  // We start by connecting to a WiFi network

  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");  
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  
  //
  // LCD SETUP
  //

  // initialize and clear display
  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.clearDisplay();
  display.display();
  
  // display a pixel in each corner of the screen
  //  display.drawPixel(0, 0, WHITE);
  //  display.drawPixel(127, 0, WHITE);
  //  display.drawPixel(0, 63, WHITE);
  //  display.drawPixel(127, 63, WHITE);
  
  // display a line of text
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(0,0);
  display.print("Display inited!");
  
  // update display with all of the above graphics
  display.display();
  
}

//
//  ==========
//  START LOOP
//  ==========
//

int value = 0;

void loop() {
  delay(1000);
  ++value;

  Serial.print("connecting to ");
  Serial.println(host);

  // Use WiFiClient class to create TCP connections
  WiFiClient client;
  client.setTimeout(1000);
  const int httpPort = 80;
  if (!client.connect(host, httpPort)) {
    Serial.println("connection failed");  
    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: keep-alive\r\n\r\n");
  unsigned long timeout = millis();
  while (client.available() == 0) {
    if (millis() - timeout > 5000) {
      Serial.println(">>> Client Timeout !");
      client.stop();
      //
      // Change display to not connected.
      //
      display.setCursor(0,0);
      display.print('X');
      display.display();
      return;
    }
  }

String line;
bool in_message=false;

  while(client.available()){
    char ch = client.read();

    if (ch == '~'){
      // We are in a message block
      in_message=true;
    }
    
    if (in_message == true && ch !='*' && ch !='~'){
      // if we're in the message and not a start/stop char:
      line += ch;
    }

    if (ch =='*'){
      // This is the end char, so print line to display
      // and clear the contents of line, until next * is 
      // received.
      display.setCursor(0,0);
      display.clearDisplay();
      display.print(line);
      String line; // clear the line
      display.display();
    }
  }

  Serial.println();
  Serial.println("closing connection");
}