gridballast · aperley · May 14, 2018 · Jul 11, 2018 · Jul 11, 2018
diff --git a/.gitmodules b/.gitmodules
@@ -10,3 +10,6 @@
 [submodule "Support/esp-idf"]
 	path = Support/esp-idf
 	url = https://github.com/WiseLabCMU/esp-idf.git
+[submodule "Source/framework/components/http-parser/http-parser"]
+	path = Source/framework/components/http-parser/http-parser
+	url = https://github.com/nodejs/http-parser.git
diff --git a/README.md b/README.md
@@ -56,3 +56,16 @@ This small accessory board holds the connector to support CTA2045 and other RS48
     ```
     $ make flash
     ```
+
+# Runtime Configuration
+The WiFi SSID and password can be configured at runtime (without recompiling and reflashing the module). Other parameters could be added as necessary.
+Configuration parameters are stored in flash using the [NVS Library](http://esp-idf.readthedocs.io/en/latest/api-reference/storage/nvs_flash.html).
+On initialization of the wifi module, if stored wifi configuration parameters exist, they are loaded and used to connect to wifi.
+If no parameters exist, the module launches configuration mode.
+
+In configuration mode, the module broadcasts a wifi network named "gridballast". A user can connect to the gridballast network and open
+http://[module-ip]/ (by default 192.168.1.4, can be found programatically with `tcpip_adapter_get_ip_info`) in a web browser. The module will present a webpage where the SSID and password can be configured.
+To exit configuration mode, the module must be rebooted.
+
+TODO: Gridballast should also support entering configuration mode by pushing a button.
+This can be done by calling `wifi_enter_config_mode()` (see `Source/framework/main/include/wifi_module.h`).
diff --git a/Source/framework/components/http-parser/component.mk b/Source/framework/components/http-parser/component.mk
@@ -0,0 +1,3 @@
+COMPONENT_ADD_INCLUDEDIRS = http-parser
+COMPONENT_SRCDIRS = http-parser
+COMPONENT_OBJS = http-parser/http_parser.o
diff --git a/Source/framework/components/http-parser/http-parser b/Source/framework/components/http-parser/http-parser
diff --git a/Source/framework/main/config.c b/Source/framework/main/config.c
@@ -0,0 +1,53 @@
+/**
+ * @file config.c
+ *
+ * @brief manage config data saved in nonvolatile storage
+ *
+ * @author Aaron Perley <[email protected]>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "esp_system.h"
+#include "esp_wifi.h"
+#include "esp_log.h"
+#include "nvs_flash.h"
+#include "nvs.h"
+#include "config.h"
+
+static const char *TAG = "config";
+static nvs_handle handle = 0;
+
+void config_init() {
+    esp_err_t err = nvs_flash_init();
+    if (err == ESP_ERR_NVS_NO_FREE_PAGES) {
+        // NVS partition was truncated and needs to be erased
+        ESP_LOGI(TAG, "Erasing and reinitializing NVS partition");
+        ESP_ERROR_CHECK(nvs_flash_erase());
+        err = nvs_flash_init();
+    }
+    ESP_ERROR_CHECK(err);
+
+    ESP_ERROR_CHECK(nvs_open("config", NVS_READWRITE, &handle));
+    ESP_LOGI(TAG, "NVS handle opened");
+}
+
+esp_err_t config_get_wifi(char *ssid, size_t ssid_len, char *password, size_t password_len) {
+    esp_err_t err = nvs_get_str(handle, "ssid", ssid, &ssid_len);
+    if (err != ESP_OK) {
+        return err;
+    }
+
+    err = nvs_get_str(handle, "pass", password, &password_len);
+    return err;
+}
+
+esp_err_t config_set(const char *field, const char *val) {
+    ESP_LOGI(TAG, "config setting %s = %s", field, val);
+    return nvs_set_str(handle, field, val);
+}
+
+esp_err_t config_commit() {
+    return nvs_commit(handle);
+}
diff --git a/Source/framework/main/config_server.c b/Source/framework/main/config_server.c
@@ -0,0 +1,115 @@
+/**
+ * @file config_server.h
+ *
+ * @brief serve configuration webpage
+ *
+ * @author Aaron Perley <[email protected]>
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include "config.h"
+#include "esp_log.h"
+#include "http_server.h"
+#include "http_parser.h"
+#include "nvs.h"
+
+static const char *TAG = "config_server";
+
+static const char * const config_html_fmt =
+"<!DOCTYPE html>"
+"<html>"
+"<body>"
+"<form action=\"/\" method=\"post\">"
+	"<label>SSID</label><input type=\"text\" name=\"ssid\" value=\"%s\"><br>"
+	"<label>Password</label><input type=\"text\" name=\"pass\" value=\"%s\"><br>"
+	"<input type=\"submit\" value=\"Submit\">"
+"</form>"
+"</body>"
+"</html>";
+
+static void send_html(http_client_conn_t *conn) {
+    // try to read saved wifi config
+    char ssid[ssid_maxlen] = "";
+    char pass[pass_maxlen] = "";
+    esp_err_t err = config_get_wifi(ssid, ssid_maxlen, pass, pass_maxlen);
+    if (err != ESP_ERR_NVS_NOT_FOUND) {
+        ESP_ERROR_CHECK(err);
+    }
+
+	int buf_len = snprintf(NULL, 0, config_html_fmt, ssid, pass);
+	char *buf = malloc(buf_len + 1);
+	if (buf == NULL) {
+		return;
+	}
+	snprintf(buf, buf_len + 1, config_html_fmt, ssid, pass);
+
+    http_client_send(conn, buf);
+	free(buf);
+}
+
+static void handle_get(http_client_conn_t *conn) {
+    ESP_LOGI(TAG, "Got GET request");
+	send_html(conn);
+}
+
+static void parse_body(char *body) {
+    char *field = strtok(body, "=");
+    int fields_set = 0;
+	while (field != NULL) {
+        if (strcmp(field, "ssid") != 0 && strcmp(field, "pass") != 0) {
+            ESP_LOGE(TAG, "Unknown form field %s", field);
+            return;
+        }
+
+        // copy from body into field
+        char *val = strtok(NULL, "&");
+        if (val == NULL) {
+            return;
+        }
+
+        // support spaces in value (which get encoded into +s)
+        for (char *chr = val; *chr != '\0'; chr++) {
+            if (*chr == '+') {
+                *chr = ' ';
+            }
+        }
+        ESP_ERROR_CHECK(config_set(field, val));
+        fields_set++;
+
+        // advance to next field
+        field = strtok(NULL, "=");
+    }
+
+    if (fields_set == 2) {
+        ESP_ERROR_CHECK(config_commit());
+    }
+}
+
+static void handle_post(http_client_conn_t *conn, char *body) {
+    ESP_LOGI(TAG, "Got POST request %s", body);
+	parse_body(body);
+	send_html(conn);
+}
+
+static void req_handler(http_client_conn_t *client_conn, http_req_t *req) {
+    if (strcmp(req->url, "/") == 0) {
+        // only serve index route
+        switch(req->method) {
+            case HTTP_GET:
+                handle_get(client_conn);
+                break;
+            case HTTP_POST:
+                handle_post(client_conn, req->body);
+                break;
+            default:
+                ESP_LOGE(TAG, "Unsupported HTTP method %d", req->method);
+                break;
+        }
+    }
+}
+
+// Interface functions
+void config_server_run() {
+    http_server_run(80, req_handler);
+}