作为博客园的处女作，本文将引导大家理解Web Server的原理。

Table of contents

1.   常见Web Server及其功能
2.   低功耗WiFi
3.   嵌入式Web Server的应用
4.   Energia Project无缝支持Arduino框架在TI LaunchPad上的扩展
5.   基于CC3200如何构建一个嵌入式Web Server

做过Web开发的同学都知道，Web Server是用来处理http（POST、GET、PUT、DELETE等）请求的系统，有大名鼎鼎的Apache http Server，也有企业应用中的Microsoft IIS。

 

我们在IE输入URL：192.168.18.108/cc3200, 登陆到CC3200构建的Web Server上,其中，cc3200是统一资源标示符，可在Energia中修改。

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Energia是个什么东西？他是TI从Arduino那边Fork过来的，正对MSP430等TI的芯片重新封装的一个IDE。非常适合学生，创客使用。

 

/*  Copyright (c) 2014 等风的猪.  This program is free software; you can redistribute it and/or  modify it under the terms of the GNU Lesser 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  Lesser General Public License for more details.  You should have received a copy of the GNU Lesser General Public  License along with this program; if not, see 
     .*/#include "SPI.h"#include "WiFi.h"#include "WebServer.h"//your network name and passwordchar ssid[] = "COAP-STATION";char password[] = "这个真不能告诉你";// CHANGE THIS TO YOUR OWN UNIQUE VALUEstatic uint8_t mac[6] = { 0x02, 0xAA, 0xBB, 0xCC, 0x00, 0x22 };// CHANGE THIS TO MATCH YOUR HOST NETWORKstatic uint8_t ip[4] = { 192, 168, 1, 210 }; // area 51!/* all URLs on this server will start with /buzz because of how we * define the PREFIX value.  We also will listen on port 80, the * standard HTTP service port */#define PREFIX "/cc3200"WebServer webserver(PREFIX, 80);/* the piezo speaker on the Danger Shield is on PWM output pin #3 */#define BUZZER_PIN 24/* this is the number of microseconds to wait after turning the * speaker on before turning it off. */int buzzDelay = 0;/* toggle is used to only turn on the speaker every other loopiteration. */char toggle = 0;/* This command is set as the default command for the server.  It * handles both GET and POST requests.  For a GET, it returns a simple * page with some buttons.  For a POST, it saves the value posted to * the buzzDelay variable, affecting the output of the speaker */void buzzCmd(WebServer &server, WebServer::ConnectionType type, char *, bool){  if (type == WebServer::POST)  {    bool repeat;    char name[16], value[16];    do    {      /* readPOSTparam returns false when there are no more parameters       * to read from the input.  We pass in buffers for it to store       * the name and value strings along with the length of those       * buffers. */      repeat = server.readPOSTparam(name, 16, value, 16);      /* this is a standard string comparison function.  It returns 0       * when there's an exact match.  We're looking for a parameter       * named "buzz" here. */      if (strcmp(name, "buzz") == 0)      {    /* use the STRing TO Unsigned Long function to turn the string     * version of the delay number into our integer buzzDelay     * variable */        buzzDelay = strtoul(value, NULL, 10);      }      /* handle led */      else if(strcmp(name, "red_led") == 0)      {          int16_t state = strtoul(value, NULL, 10);          boolean pin_status = (state == 1) ? HIGH : LOW;           digitalWrite(RED_LED, pin_status);          Serial.println("red button\n");          Serial.println(value);      }    } while (repeat);        // after procesing the POST data, tell the web browser to reload    // the page using a GET method.     server.httpSeeOther(PREFIX);    return;  }  /* for a GET or HEAD, send the standard "it's all OK headers" */  server.httpSuccess();  /* we don't output the body for a HEAD request */  if (type == WebServer::GET)  {    /* store the HTML in program memory using the P macro */    P(message) = ""  ""  "
     "  ""  ""  ""  ""  """"""  "
Control the Device on LaunchPad:
"  "
     
"  "
0
"  "Red Led""""";    /* send the html back to the browser */    server.printP(message);  }}void setup(){  Serial.begin(9600);  // set the PWM output for the buzzer to out  pinMode(BUZZER_PIN, OUTPUT);  pinMode(RED_LED, OUTPUT);    // setup the Ehternet library to talk to the Wiznet board  Serial.print("Attempting to connect to Network:");  Serial.print(ssid);  WiFi.begin(ssid, password);  while(WiFi.status() != WL_CONNECTED) {      Serial.print(".");      delay(300);  }  Serial.println("\nYou're connected to the network");  Serial.println("Waiting for an ip address");    while (WiFi.localIP() == INADDR_NONE) {    // print dots while we wait for an ip addresss    Serial.print(".");    delay(300);  }  // you're connected now, so print out the status    printWifiStatus();    /* register our default command (activated with the request of   * http://x.x.x.x/buzz */  webserver.setDefaultCommand(&buzzCmd);  /* start the server to wait for connections */  webserver.begin();}void loop(){  // process incoming connections one at a time forever  webserver.processConnection();  /* every other time through the loop, turn on and off the speaker if   * our delay isn't set to 0. */  if ((++toggle & 1) && (buzzDelay > 0))  {    digitalWrite(BUZZER_PIN, HIGH);    delayMicroseconds(buzzDelay);    digitalWrite(BUZZER_PIN, LOW);  }}void printWifiStatus() {  // print the SSID of the network you're attached to:  Serial.print("Network Name: ");  Serial.println(WiFi.SSID());  // print your WiFi shield's IP address:  IPAddress ip = WiFi.localIP();  Serial.print("IP Address: ");  Serial.println(ip);  // print the received signal strength:  long rssi = WiFi.RSSI();  Serial.print("signal strength (RSSI):");  Serial.print(rssi);  Serial.println(" dBm");}