Hi all,
Apologies for yet another topic on this but I have tried all sorts of things and cant reliably get this working quickly so any tips or pointers would be much appreciated. The most obvious delays are:
- After the last byte has been loaded it takes a while for the page spinner to stop spinning - maybe 2-3seconds.
- It takes a bit of time to get the first request but presumably this is just the time to connect to the various servers
- You can see the individual chunks of JSON data appear one by one, with a delay of maybe 200ms between them.
The overall page load is 6-7seconds with a 5kb JSON, though based on the actual page loading I would say it only takes 500ms for the data to appear out of the 6-7s total time.
Summary: I have a server device in my house with a TCP API on a custom port, and if you send it JSON queries then it will respond with the answers in JSON format. I have written an ESP8266 bridge so that you can send the JSON through a normal webpage (with an argument) to a page, it will take the argument and make the request from the API before passing back the response to the requester (it will also include the requester and the requested JSON).
This seems to work ok on small JSON responses from the API server (~5kB), but if this JSON response goes up to 20kB then it selectively doesn't finish the request, even though going from 5-10kb seems to only take a few hundred ms longer.
I have tried setting various noDelay flags, changing the timeout and also changing the packet size but have so far failed. I even tried creating a 20kB char array and downloading the whole response from server before passing it back to the requester, which worked ok sometimes, but then obviously fails if you reach 20.1kB and you quickly run out of memory aswell!
I am using about 30% of storage and 45% of dynamic memory so should be plenty of space, hence I'd love to hear your thoughts on speeding it up. Is there a stream implementation that would be better, or can I do things in a different order to speed things up?
Thanks very much in advance
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <WiFiUdp.h>
#include <ESP8266WebServer.h>
#include <ESP8266HTTPUpdateServer.h>
#include <WiFiManager.h>
#include <ArduinoOTA.h>
#include <EEPROM.h>
//No longer needed as reading JsonChunkSize bytes at a time
//#include <PrintEx.h>
#define JsonChunkSize 2920
char jsontext[JsonChunkSize];
#define JsonHeaderText "HTTP/1.1 200 OK\r\nContent-Type: application/json;charset=utf-8\r\nServer: Hub Bridge\r\nConnection: close\r\n\r\n"
//////////////////////////////////////////////////////////////////////////////////
ESP8266WebServer server(80);
ESP8266HTTPUpdateServer httpUpdater;
void handleRoot() {
//This returns the 'homepage' with links to each other main page
char szTmp[1024];
sprintf(szTmp, "<html>Web Commands
<a href='/relay'>Hub Relay</a></html>");
server.send(200, "text/html", szTmp);
}
void handleRelay() {
//Start building the response with the original request and then add in the hub response
char commandchararray[500];
char devicechararray[50];
int commandlength;
bool has_device_arg = false;
if (server.hasArg("command")){
//If we have a command then lets log it for manipulation
strncpy(commandchararray, server.arg("command").c_str(), 499);
//Ensure the ending is null char
commandchararray[499] = '\0';
Serial.println(commandchararray);
commandlength = strlen(commandchararray);
if (server.hasArg("device")) {
has_device_arg = true;
strncpy(devicechararray, server.arg("device").c_str(), 49);
devicechararray[49] = '\0';
}
}
else {
//No command so send a response to say so
Serial.println("No command received");
WiFiClient client;
client = server.client();
client.print(JsonHeaderText);
client.print("{\"No command received\":\"Add /?command=blahblahblah\"}");
client.stop();
return;
}
strcpy(jsontext, "{\"relaycommand\": ");
strcat(jsontext, commandchararray);
strcat(jsontext, ",\r\n");
if (has_device_arg) {
strcat(jsontext, "\"relaydevice\": \"");
strcat(jsontext, devicechararray);
strcat(jsontext, "\",\r\n");
}
strcat(jsontext, "\"relayresult\":");
WiFiClient client; //This is main for the requester
WiFiClient hubsrv; //This is for the Hub
//Tried all of these with different varieties with no luck
//client.setNoDelay(true);
//hubsrv.setNoDelay(true);
//client.setTimeout(200);
//hubsrv.setTimeout(200);
if (hubsrv.connect("192.168.1.100", 424)) {
Serial.println("Connected to hub");
}
else {
Serial.println("Connection to hub failed");
return;
}
//Send command with the \0 otherwise the server rejects the command
hubsrv.write((const uint8_t *)commandchararray, commandlength+1);
//Now set up the client for printing the return
client = server.client();
client.print(JsonHeaderText);
client.print(jsontext);
//Just have this wait in case the response is not back from hub yet
unsigned long timeout = millis();
while (hubsrv.available() == 0) {
if (millis() - timeout > 8000) {
Serial.println(">>> Client Timeout !");
hubsrv.stop();
client.stop();
return;
}
}
while(hubsrv.available()){
hubsrv.readBytes(jsontext, JsonChunkSize-1);
jsontext[JsonChunkSize-1] = '\0';
client.print(jsontext);
}
client.print("}\r\n");
//Now we should close the connection to the client and hub
hubsrv.stop();
client.stop();
}
void handleNotFound(){
String message = "File Not Found\n\n";
message += "URI: ";
message += server.uri();
message += "\nMethod: ";
message += (server.method() == HTTP_GET)?"GET":"POST";
message += "\nArguments: ";
message += server.args();
message += "\n";
for (uint8_t i=0; i<server.args(); i++){
message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
}
server.send(404, "text/plain", message);
}
void setup(void){
Serial.begin(9600); //enable Serial if we need it for debugging
WiFiManager wifiManager;
//reset settings - for testing
//wifiManager.resetSettings();
wifiManager.setTimeout(180);
//fetches ssid and pass and tries to connect
//if it does not connect it starts an access point with the specified name
//and goes into a blocking loop awaiting configuration
if(!wifiManager.autoConnect("HubRelayBridge")) {
Serial.println("failed to connect and hit timeout");
delay(3000);
//reset and try again, or maybe put it to deep sleep
ESP.reset();
delay(5000);
}
Serial.println("WiFi Connected - Local IP:");
Serial.println(WiFi.localIP());
server.on("/", handleRoot);
server.on("/relay", handleRelay);
//server.on("/config", HTTP_POST, handleConfig);
//Link the HTTP Updater with the web sesrver
httpUpdater.setup(&server);
//Start listening for OTA update requests
ArduinoOTA.begin();
//Use default password
ArduinoOTA.setPassword((const char *)"123");
server.onNotFound(handleNotFound);
server.begin();
Serial.println("WiFi Server Started");
}
void loop(void){
ArduinoOTA.handle();
server.handleClient();
}
Here is the Chrome breakdown of loading time:
Queueing 4.00 ms
Connection Start TIME
Stalled 247.00 ms
DNS Lookup 0
Initial connection 1.61 s
Request/Response TIME
Request sent 0
Waiting (TTFB) 10.00 ms
Content Download 4.44 s
Total 6.32s
Haha, you're right. It was sized to be 1kb as I originally had other things in it, but then strimmed everything down to try and understand if there were any other factors affecting the loading speed.