Added start of HTTP server (& data storage)

components/http_server/CMakeLists.txt

@@ -0,0 +1,4 @@
+idf_component_register(SRCS "http.c"
+  INCLUDE_DIRS "."
+  PRIV_REQUIRES dht22 wifi esp_http_server 
+)

components/http_server/Kconfig.projbuild

@@ -0,0 +1,14 @@
+menu "HTTP"
+#    config WIFI_SSID
+#        string "WiFi SSID"
+#        default "VM8094728"
+#        help
+#            SSID (network name) for the example to connect to.
+
+#    config WIFI_PASSWORD
+#        string "WiFi Password"
+#        default "tx3YrxvzMrbr"
+#        help
+#            WiFi password (WPA or WPA2) for the example to use.
+
+endmenu

components/http_server/http.c

@@ -0,0 +1,98 @@
+#include "http.h"
+#include "esp_sntp.h"
+#include "wifi.h"
+#include <math.h>
+#include <stdlib.h>
+#include "esp_log.h"
+#include "esp_http_server.h"
+
+// 2 Days worth of samples
+#define NUM_SAMPLES_TO_STORE (( 24  *   60 ) / 10 ) * 2
+
+typedef struct {
+  uint8_t myt_sec;   // 0 -> 61
+  uint8_t myt_min;   // 0 -> 59
+  uint8_t myt_hour;  // 0 -> 23
+  uint8_t myt_day;   // 1 -> 31
+  uint8_t myt_month; // 0 -> 11 !!
+  uint8_t myt_year;  // years since 1900
+} my_time;
+
+typedef struct {
+  deci_percent rh;
+  deci_degrees_c temp;
+  my_time time;
+} my_dht22_data;
+
+
+// I know this is asking for a race condition...
+static my_dht22_data *dht22_buffer = NULL;
+static int dht22_num = 0;
+
+my_time get_time() {
+  time_t epoch;
+  time(&epoch);
+  struct tm *timeinfo = localtime(&epoch);
+  my_time my_current_time;
+
+  // There must be a better way - I couldn't figure out how to do it
+  // nicely all at once
+  my_current_time.myt_sec = timeinfo->tm_sec;
+  // -5 to get the middle of the averaged window
+  my_current_time.myt_min = timeinfo->tm_min;
+  my_current_time.myt_hour = timeinfo->tm_hour;
+  my_current_time.myt_day = timeinfo->tm_mday;
+  my_current_time.myt_month = timeinfo->tm_mon;
+  my_current_time.myt_year = timeinfo->tm_year;
+  return my_current_time;
+}
+
+
+esp_err_t dht22_data_get_handler(httpd_req_t *req) {
+  char *resp;
+
+  size_t size_of_csv_line = strlen("YYYY:MM:DD HH:MM:SS,XXXX,YYYY\n");
+
+  resp = calloc(dht22_num, size_of_csv_line + 1);
+
+  for (int i = 0; i < dht22_num; i++) {
+    my_dht22_data d = dht22_buffer[i];
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wformat-truncation"
+    snprintf(resp + (i * size_of_csv_line), size_of_csv_line,
+             "%04d:%02d:%02d %02d:%02d:%02d\t%04d\t%04d\n", d.time.myt_year,
+             d.time.myt_month, d.time.myt_day, d.time.myt_hour, d.time.myt_min,
+             d.time.myt_sec, d.rh, d.temp);
+#pragma GCC diagnostic pop
+  }
+  // shouldn't need to null terminate this becuase of calloc
+
+  httpd_resp_send(req, resp, HTTPD_RESP_USE_STRLEN);
+  return ESP_OK;
+}
+
+/* URI handler structure for GET /uri */
+httpd_uri_t dht22_data_get = {
+    .uri      = "/dht22.csv",
+    .method   = HTTP_GET,
+    .handler  = dht22_data_get_handler,
+    .user_ctx = NULL
+};
+
+void init_dht22_data() {
+  dht22_buffer = malloc(NUM_SAMPLES_TO_STORE * sizeof(my_dht22_data));
+  // register an http endpoint thingy probably?
+}
+
+void add_dht22_data(float rh, float temp) {
+  if (dht22_buffer == NULL) {
+    return;
+  }
+  my_dht22_data dht22_data;
+  dht22_data.time = get_time();
+  dht22_data.time.myt_min -= 5;
+  dht22_data.temp = round(temp);
+  dht22_data.rh = round(rh);
+  dht22_buffer[dht22_num] = dht22_data;
+  dht22_num++;
+}

components/http_server/http.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include "dht22.h"
+
+void init_dht22_data();
+
+// This function presumes we've got a 10 minute average here
+//  - could think about abstracting the average out into this
+//  function maybe. Something for the future!
+void add_dht22_data(float rh, float temp);