ESP simplest server

ESP8266/esp8266.c

@@ -0,0 +1,170 @@
+/*
+ * This file is part of the esp8266 project.
+ * Copyright 2025 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <usefull_macros.h>
+#include <stdio.h>
+
+#include "esp8266.h"
+#include "serial.h"
+
+#define ESPMSG(x)  do{if(!serial_send_msg(x)) return FALSE;}while(0)
+
+// sometimes ESP hangs with message "WIFI GOT IP" and I can do nothing except waiting
+
+const char *msgptr = NULL; // pointer to received message
+static int receivedlen = 0;
+
+// check module working
+int esp_check(){
+    // try simplest check for three times
+    for(int i = 0; i < 3; ++i) if( ANS_OK == serial_sendwans("AT")) break;
+    //esp_close();
+    // now try next even if no answer for "AT"
+    if( ANS_OK == serial_sendwans("ATE0") // echo off
+        && ANS_OK == serial_sendwans("AT+CWMODE_CUR=1") // station mode
+        ) return TRUE;
+    return FALSE;
+}
+
+// check established wifi connection
+esp_cipstatus_t esp_cipstatus(){
+    if(ANS_OK != serial_sendwans("AT+CIPSTATUS")) return ESP_CIP_FAILED;
+    char *l = serial_getline(NULL, NULL);
+    const char *n = NULL;
+    if(!l || !(n = serial_tidx(l, "STATUS:"))) return ESP_CIP_FAILED;
+    return (esp_cipstatus_t)serial_s2i(n);
+}
+
+// connect to AP
+int esp_connect(const char *SSID, const char *pass){
+    ESPMSG("AT+CWJAP_CUR=\"");
+    ESPMSG(SSID);
+    ESPMSG("\",\"");
+    ESPMSG(pass);
+    if(ANS_OK != serial_sendwans("\"")) return FALSE;
+    return TRUE;
+}
+
+// just send AT+CIFSR
+int esp_myip(){
+    return (ANS_OK == serial_sendwans("AT+CIFSR"));
+}
+
+// start server on given port
+int esp_start_server(const char *port){
+    if(ANS_OK != serial_sendwans("AT+CIPMUX=1")){ // can't start server without mux
+        // what if already ready?
+        char *x = serial_getline(NULL, NULL);
+        if(!x || !serial_tidx(x, "link is builded")) return FALSE;
+    }
+    ESPMSG("AT+CIPSERVER=1,");
+    if(ANS_OK != serial_sendwans(port)) return FALSE;
+    return TRUE;
+}
+
+// stop server
+int ep_stop_server(){
+    return (ANS_OK == serial_sendwans("AT+CIPSERVER=0"));
+}
+
+// next (or only) line of received data
+const char *esp_msgline(){
+    DBG("receivedlen=%d", receivedlen);
+    if(msgptr){
+        const char *p = msgptr;
+        msgptr = NULL;
+        return p;
+    }
+    if(receivedlen < 1) return NULL;
+    int l, d;
+    const char *got = serial_getline(&l, &d);
+    receivedlen -= l + d;
+    return got;
+}
+
+// process connection/disconnection/messages
+// fd - file descriptor of opened/closed connections
+esp_clientstat_t esp_process(int *fd){
+    msgptr = NULL;
+    receivedlen = 0;
+    int l, d;
+    char *got = serial_getline(&l, &d);
+    if(!got) return ESP_CLT_IDLE;
+    const char *x = serial_tidx(got, "+IPD,");
+    if(x){
+        if(fd) *fd = serial_s2i(x);
+        x = serial_tidx(x, ",");
+        if(!x) return ESP_CLT_ERROR;
+        int r = serial_s2i(x);
+        x = serial_tidx(x, ":");
+        if(!x) return ESP_CLT_ERROR;
+        receivedlen = r - d - (l - (x-got)); // this is a rest of data (if any)
+        msgptr = x;
+        return ESP_CLT_GETMESSAGE;
+    }
+    // check for CONNECT/CLOSE
+    if((x = serial_tidx(got, ",CONNECT"))){
+        if(fd) *fd = serial_s2i(got);
+        return ESP_CLT_CONNECTED;
+    }
+    if((x = serial_tidx(got, ",CLOSED"))){
+        if(fd) *fd = serial_s2i(got);
+        return ESP_CLT_DISCONNECTED;
+    }
+    DBG("Unknown message: '%s'", got);
+    return ESP_CLT_IDLE;
+}
+
+int esp_send(int fd, const char *msg){
+    DBG("send '%s' to %d", msg, fd);
+    ESPMSG("AT+CIPSENDEX=");
+    if(!serial_putchar('0' + fd)) return FALSE;
+    if(ANS_OK != serial_sendwans(",2048")) return FALSE;
+    int got = 0;
+    // try several times
+    for(int i = 0; i < 10; ++i){
+        got = serial_getch();
+        if(got == '>') break;
+    }
+    if(got != '>'){
+        DBG("Didn't found '>'");
+        serial_send_msg("\\0"); // terminate message
+        serial_clr();
+        return FALSE; // go into terminal mode
+    }
+    serial_clr(); // remove space after '>'
+    ESPMSG(msg);
+    if(ANS_OK == serial_sendwans("\\0")) return TRUE;
+    DBG("Didn't sent");
+    return FALSE;
+}
+
+void esp_reset(){
+    serial_sendwans("AT+RST");
+}
+
+void esp_close(){
+    serial_sendwans("AT+CIPMUX=0");
+    serial_sendwans("AT+CIPCLOSE");
+}
+
+
+int esp_listAP(){
+    if(ANS_OK == serial_sendwans("AT+CWLAP")) return TRUE;
+    return FALSE;
+}