Zoltan Hudak
Tiny HTTP server controlling a DigitalOutput.
Turn LED1, or other digital output, on/off using a web browser.
In this example we create a HTTP server for the STM32F407VET6 black board that will serve a simple Web page to remotely turn LED1, or other digital output, on/off by using a web browser.
 |  | ||
Notice that DHCP is turned on by default. The IP address assigned to the WebSwitch server along with an instruction how to use it is printed to the connected PC's serial terminal window during program start up.
To use static IP address uncomment and adjust line #221 in main.cpp.
A DP83848 module is used as Ethernet interface.
Wiring
| DP83848 module | STM32F407VET6 board | |||
|---|---|---|---|---|
| VCC | <=> | +3.3V | ||
| GND | <=> | GND | ||
| MDIO | <=> | PA_2 | ||
| MDC | <=> | PC_1 | ||
| OSCIN | <=> | PA_1 | ||
| CRS | <=> | PA_7 | ||
| RX0 | <=> | PC_4 | ||
| RX1 | <=> | PC_5 | ||
| TX_EN | <=> | PB_11 | ||
| TX0 | <=> | PB_12 | ||
| TX1 | <=> | PB_13 |
Notice that because the RX_ER line is not used the DP83848 module doesn't have to be modified.
The project was inspired by the Tuxgraphics Web Switch. Thank you Guido!
Diff: main.cpp
- Revision:
- 0:912fb893b03c
- Child:
- 1:cae77ef9edaf
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sat May 18 09:04:25 2019 +0000
@@ -0,0 +1,307 @@
+#include "mbed.h"
+#include "EthernetInterface.h"
+#include "TCPServer.h"
+#include "TCPSocket.h"
+#include <stdio.h>
+#include <string>
+
+using namespace std;
+
+#define IP "192.168.1.181"
+#define GATEWAY "192.168.1.1"
+#define NETMASK "255.255.255.0"
+#define PORT 80
+
+Serial pc(PC_6, PC_7);
+//Serial pc(PA_9, PA_10);
+
+EthernetInterface* net;
+
+TCPSocket server;
+TCPSocket* clientSocket;
+SocketAddress clientAddress;
+char receiveBuf[1024] = { };
+
+const int OFF = 1;
+const int ON = 0;
+
+DigitalOut sw(PA_6);
+float roomTemp = 21.8; // A temperature sensor output
+
+const string PASSWORD = "secret"; // change as you like
+const string HTTP_OK = "HTTP/1.0 200 OK";
+const string MOVED_PERM = "HTTP/1.0 301 Moved Permanently\r\nLocation: ";
+const string UNAUTHORIZED = "HTTP/1.0 401 Unauthorized";
+string httpHeader; // HTTP header
+string httpContent; // HTTP content
+
+/**
+ * @brief Analyses the received URL
+ * @note The string passed to this function will look like this:
+ * GET /password HTTP/1.....
+ * GET /password/ HTTP/1.....
+ * GET /password/?sw=1 HTTP/1.....
+ * GET /password/?sw=0 HTTP/1.....
+ * @param url URL string
+ * @retval -1 invalid password
+ * -2 no command given but password valid
+ * -3 just refresh page
+ * 0 switch off
+ * 1 switch on
+ */
+int8_t analyseURL(string& url) {
+ if(url.substr(5, PASSWORD.size()) != PASSWORD)
+ return(-1);
+
+ uint8_t pos = 5 + PASSWORD.size();
+
+ if(url.substr(pos, 1) == " ")
+ return(-2);
+
+ if(url.substr(pos++, 1) != "/")
+ return(-1);
+
+ string cmd(url.substr(pos, 5));
+
+ if(cmd == "?sw=0")
+ return(0);
+
+ if(cmd == "?sw=1")
+ return(1);
+
+ return(-3);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+string& movedPermanently(uint8_t flag) {
+ if(flag == 1)
+ httpContent = "/" + PASSWORD + "/";
+ else
+ httpContent = "";
+
+ httpContent += "<h1>301 Moved Permanently</h1>\r\n";
+
+ return(httpContent);
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+string& showWebPage(uint8_t status) {
+ char roomTempStr[5];
+
+ //roomTemp = ds1820.read();
+ sprintf(roomTempStr, "%3.1f", roomTemp);
+
+ // CSS toggle switch
+ httpContent = "<head>";
+ httpContent += "<style>";
+
+ httpContent += ".switch {";
+ httpContent += "position: relative;";
+ httpContent += "display: inline-block;";
+ httpContent += "width: 60px;";
+ httpContent += "height: 34px;";
+ httpContent += "}";
+
+ httpContent += ".switch input {display:none;}";
+
+ httpContent += ".slider {";
+ httpContent += "position: absolute;";
+ httpContent += "cursor: pointer;";
+ httpContent += "top: 0;";
+ httpContent += "left: 0;";
+ httpContent += "right: 0;";
+ httpContent += "bottom: 0;";
+ httpContent += "border-radius: 34px;";
+ httpContent += "background-color: #ccc;";
+ httpContent += "-webkit-transition: .4s;";
+ httpContent += "transition: .4s;";
+ httpContent += "}";
+
+ httpContent += ".slider:before {";
+ httpContent += "position: absolute;";
+ httpContent += "content: \"\";";
+ httpContent += "height: 26px;";
+ httpContent += "width: 26px;";
+ httpContent += "left: 4px;";
+ httpContent += "bottom: 4px;";
+ httpContent += "border-radius: 50%;";
+ httpContent += "background-color: white;";
+ httpContent += "-webkit-transition: .4s;";
+ httpContent += "transition: .4s;";
+ httpContent += "}";
+
+ httpContent += "input:checked + .slider {";
+ httpContent += "background-color: #8ce196;";
+ httpContent += "}";
+
+ httpContent += "input:focus + .slider {";
+ httpContent += "box-shadow: 0 0 1px #8ce196;";
+ httpContent += "}";
+
+ httpContent += "input:checked + .slider:before {";
+ httpContent += "-webkit-transform: translateX(26px);";
+ httpContent += "-ms-transform: translateX(26px);";
+ httpContent += "transform: translateX(26px);";
+ httpContent += "}";
+
+ httpContent += "</style>";
+ httpContent += "</head>";
+
+ httpContent += "<body>";
+ httpContent += "<h2><a href=\".\" title=\"Click to refresh the page\">Smart Home</a></h2>";
+ httpContent += "<pre>Temperature:\t" + string(roomTempStr) + "°C</pre>";
+ httpContent += "<pre>Heating:\t";
+
+ if(status == ON) {
+ httpContent += "<a href=\"./?sw=0\" class=\"switch\"> ";
+ httpContent += "<input type=\"checkbox\" checked>";
+ }
+ else {
+ httpContent += "<a href=\"./?sw=1\" class=\"switch\"> ";
+ httpContent += "<input type=\"checkbox\">";
+ }
+
+ httpContent += "<div class=\"slider\"></div>";
+ httpContent += "</a></pre>";
+ httpContent += "<hr>";
+ httpContent += "<pre>2017 ARMmbed</pre>";
+ httpContent += "</body>";
+
+ return httpContent;
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+void sendHTTP(TCPSocket& client, string& header, string& content) {
+ char content_length[5] = { };
+
+ header += "\r\nContent-Type: text/html\r\n";
+ header += "Content-Length: ";
+ sprintf(content_length, "%d", content.length());
+ header += string(content_length) + "\r\n";
+ header += "Pragma: no-cache\r\n";
+ header += "Connection: About to close\r\n";
+ header += "\r\n";
+
+ string webpage = header + content;
+ client.send((char*)webpage.c_str(), webpage.length());
+ pc.printf("HTTP message sent to client.\n\r");
+}
+
+/**
+ * @brief
+ * @note
+ * @param
+ * @retval
+ */
+int main(void) {
+ pc.printf("Starting.. \r\n\r\n");
+
+ net = new EthernetInterface();
+
+ if (!net) {
+ pc.printf("Error! No network inteface found.\n");
+ return 0;
+ }
+
+ //net->set_network (IP, NETMASK, GATEWAY); // include this for using static IP address
+
+ nsapi_size_or_error_t r = net->connect();
+ if (r != 0) {
+ pc.printf("Error! net->connect() returned: %d\n", r);
+ return r;
+ }
+
+ // Show the network address
+ const char *ip = net->get_ip_address();
+ const char *netmask = net->get_netmask();
+ const char *gateway = net->get_gateway();
+ pc.printf("IP address: %s\r\n", ip ? ip : "None");
+ pc.printf("Netmask: %s\r\n", netmask ? netmask : "None");
+ pc.printf("Gateway: %s\r\n\r\n", gateway ? gateway : "None");
+ pc.printf("Usage: Type %s/%s/ into your web browser and hit ENTER\r\n\r\n", ip, PASSWORD.c_str());
+
+ /* Open the server on ethernet stack */
+ server.open(net);
+
+ /* Bind the HTTP port (TCP 80) to the server */
+ server.bind(ip, PORT);
+
+ /* Can handle 5 simultaneous connections */
+ server.listen(5);
+
+ //listening for http GET request
+ while(true) {
+ pc.printf("=========================================\r\n");
+ //server.accept(&clientSocket, &clientAddress);
+ nsapi_error_t error;
+ clientSocket = server.accept(&error);
+ if (error != 0) {
+ pc.printf("Connection failed!\r\n");
+ continue;
+ }
+ clientSocket->getpeername(&clientAddress);
+ pc.printf("Client with IP address %s connected.\r\n\r\n", clientAddress.get_ip_address());
+ clientSocket->recv(receiveBuf, 1023);
+ pc.printf("Data received:\r\n%s\n\r", receiveBuf);
+
+ string received(receiveBuf);
+
+ if(received.substr(0, 3) != "GET") {
+ httpHeader = HTTP_OK;
+ httpContent = "<h1>200 OK</h1>";
+ sendHTTP(*clientSocket, httpHeader, httpContent);
+ continue;
+ }
+
+ if(received.substr(0, 6) == "GET / ") {
+ httpHeader = HTTP_OK;
+ httpContent = "<p>Usage: Type http://ip_address/password/ into your web browser and hit ENTER</p>\r\n";
+ sendHTTP(*clientSocket, httpHeader, httpContent);
+ continue;
+ }
+
+ int cmd = analyseURL(received);
+
+ if(cmd == -2) {
+
+ // redirect to the right base url
+ httpHeader = MOVED_PERM;
+ sendHTTP(*clientSocket, httpHeader, movedPermanently(1));
+ continue;
+ }
+
+ if(cmd == -1) {
+ httpHeader = UNAUTHORIZED;
+ httpContent = "<h1>401 Unauthorized</h1>";
+ sendHTTP(*clientSocket, httpHeader, httpContent);
+ continue;
+ }
+
+ if(cmd == 1) {
+ sw = ON; // turn the switch on
+ }
+
+ if(cmd == 0) {
+ sw = OFF; // turn the switch off
+ }
+
+ httpHeader = HTTP_OK;
+ sendHTTP(*clientSocket, httpHeader, showWebPage(sw));
+ clientSocket->close();
+ }
+}