c - 函数的存在会中断 HTTP 请求

Question

所以我为 Arduino 编写了一些代码，基本上只发出 HTTP 请求。这是一个 Twitter 项目，但大部分 Twitter 信息是通过 PHP 脚本收集的。 Arduino 仅用于从文本文件中收集少量文本，并根据其内容发送推文。其中包括一个文件，其中包含关注者数量(如果发生更改，则发布推文)、最后提及日期(如果发生更改，则发布推文)以及最新关注者名称(在关注者推文中用于提及用户)。

我编写了函数getLastFollowerName()来获取最后一个关注者的名字。它执行与函数 checkMentions() 和 'checkFollowers()` 相同的操作。然而，这个函数会发生一些奇怪的事情。当我实现它后，测试运行如下。

1. 获取了 followBy.txt 中包含的用户名中除两个字符之外的所有字符，然后 Arduino 代码停止运行。
2. 与 1 相同。
3. getLastFollowerName() 中的 HTTP 请求找不到两个 \r\n 字符，这意味着它们发现了一些不应该有的其他形式的响应到过。在打印此响应时，它开始打印整个 HTML 文档 header (DOCTYPE 等)，这是无意义的，因为我请求的是文本文件。
4. 所有其他 HTTP 请求(在 checkMentions() 和 checkFollowers() 中)开始出现与 getLastFollowerName() 请求相同的行为3 内完成。

所有后续运行均如 4 中所述。因此，我注释掉了 getLastFollowerName() 的函数调用，并且没有任何更改。我注释掉了该函数的代码本身，一切都开始像添加该函数之前一样工作。

所以我的问题是 - 即使该函数没有被调用，它的存在也可能会破坏 HTTP 请求，该怎么办？是代码本身，还是更可能是函数的大小？如果是后者，如果我需要该功能，我该如何解决这个问题？

编辑:抱歉，忘记粘贴代码。就是这样(删除了一些敏感信息(WiFi 信息、Twitter key 等)

#include <SPI.h>
#include <WiFi.h>
#include <Twitter.h>

int led = 9; //put at 9 and GND

char ssid[] = ""; //  your network SSID (name) 
char pass[] = "";    // your network password (use for WPA, or use as key for WEP)

int keyIndex = 0;            // your network key Index number (needed only for WEP)

int status = WL_IDLE_STATUS; // status of the wifi connection

// initialize the library instance:
WiFiClient client;

const unsigned long requestInterval = 30*1000;    // delay between requests; 30 seconds

// if you don't want to use DNS (and reduce your sketch size)
// use the numeric IP instead of the name for the server:
//IPAddress server(199,59,149,200);    // numeric IP for api.twitter.com
char server[] = "mysite.com";     // name address for twitter API

boolean requested;                     // whether you've made a request since connecting
unsigned long lastAttemptTime = 0;     // last time you connected to the server, in milliseconds

Twitter twitter(""); //token authorized from (you do NOT need to reobtain this) 

String lastCount = ""; //last number counted
String lastDate = "";
String lastFollower="";

unsigned long startTime;
const unsigned long connectTimeout = 15L * 1000L; // Max time to retry server link
int numberOfBytes=0;

void setup()
{
  // reserve space for the strings:
//  tweet.reserve(150);
  //Initialize serial and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  // check for the presence of the shield:
  if (WiFi.status() == WL_NO_SHIELD) {
    Serial.println("WiFi shield not present"); 
    // don't continue:
    while(true);
  } 

  // attempt to connect to Wifi network:
  while ( status != WL_CONNECTED) { 
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:    
    status = WiFi.begin(ssid, pass);

    // wait 10 seconds for connection:
    delay(5000);
    //delay(10000);
    //tweet("this is another test");
  }
}

void loop()
{
  while(!checkFollowers()); //keep trying until successful
  client.stop();
  while(!checkMentions()); //keep trying until successful
  client.stop();
}

boolean checkFollowers()
{
  //connectToServer();
  //delay(10000);
  String currentLine="";
  currentLine.reserve(256);
  if (client.connected())
  {
    Serial.println("Connected. Checking for availabilty of client...");
    if (client.available())
    {
      Serial.println("Client is available! Trying to read from client...");
      // read incoming bytes:

      if(client.find("\r\n\r\n"))
      {

      char inChar;
      while(inChar=client.read())
      {
        if(inChar==-1) break;
        currentLine+=inChar; //read in all characters of count
        Serial.print("\n\nCurrent follower count: " + currentLine + "\n\n");
        //if(inChar=='y' || inChar == 'n') break;
      }
      if(currentLine!=lastCount)
      //if(inChar=='y')
      {
        lastCount=currentLine;

//        while(getLastFollowerName())
//        {
//          Serial.println("follower name not yet found");
//        }
        //client.stop();
        //char finalTweet[170];
        //int n = sprintf(finalTweet, "%s%s", lastFollower, " Thanks for the follow!");
        tweet("Thanks for the tweet!");
        Serial.println("BLINKING LED");
        blink(3);
      }
      else
      {
        Serial.println("NOT BLINKING.");
        tweet("Someone should follow me!");
      }
      currentLine=""; //clear
      delay(5000); //delay 5 seconds (don't kill server)
      return true;
     }
     else
     {
       Serial.println("newlines not found - error with request");
       return false;
     }
    }
    else
    {
      Serial.println("followers not available");
      return false;
    }
  }
  else if (millis() - lastAttemptTime > requestInterval)
  {
    // if you're not connected, and two minutes have passed since
    // your last connection, then attempt to connect again:
    //runPhpScript(); //try to run PHP script to get latest info
    //connectToServer();
    makeHttpRequest("/private/followerScript.php");
    client.stop(); //cut connection after running script (I think this is what this does...)
    makeHttpRequest("/private/followerCount.txt");
    return false;
  }
  else
  {
    //Serial.print("f");
    return false;
  }
}


boolean checkMentions()
{
  String currentLine="";
  if (client.connected())
  {
    Serial.println("Connected. Checking for availabilty of client...");
    if (client.available())
    {
      Serial.println("Client is available! Trying to read from client...");
      // read incoming bytes:

      if(client.find("\r\n\r\n"))
      {

      char inChar;

//      inChar = client.read(); //read in a character
      while(inChar=client.read())
      {
        if(inChar==-1) break;
        currentLine+=inChar; //read in all characters of count
        Serial.print("\n\nCurrent mention date: " + currentLine + "\n\n");
      }
      if(currentLine!=lastDate)
      {
        lastDate=currentLine;
        Serial.println("BLINKING LED");
        tweet("Someone just mentioned me!");
        blink(3);
      }
      else
      {
        Serial.println("NOT BLINKING.");
        tweet("Someone should mention me!");
      }
      currentLine=""; //clear
      delay(5000); //delay 5 seconds (don't kill server)
      return true;
     }
     else
     {
       Serial.println("newlines not found - error with request");
       return false;
     }
    }
    else
    {
      Serial.println("mentions - not available");
      return false;
    }

  }
  else if (millis() - lastAttemptTime > requestInterval)
  {
    // if you're not connected, and two minutes have passed since
    // your last connection, then attempt to connect again:
    makeHttpRequest("/private/mentionScript.php");
    client.stop();
    makeHttpRequest("/private/mentionsDate.txt");
    return false;
  }
  else
  {
    //Serial.print("m");
    return false;
  }
}

boolean getLastFollowerName()
{
  String currentLine="";
  if (client.connected())
  {
    //Serial.println("Connected. Checking for availabilty of client...");
    if (client.available())
    {
      Serial.println("Trying to read last follower name...");

      if(client.find("\r\n\r\n"))
      {

      char inChar;

      while(inChar=client.read())
      {
        if(inChar==-1) break;
        currentLine+=inChar; //read in all characters of count
        Serial.print("\n\nLast follower: " + currentLine + "\n\n");
      }
      lastFollower = currentLine; //store globally
      return true;
     }
     else
     {
       Serial.println("newlines not found - error with request");
       return false;
     }
    }
    else
    {
      return false;
    }
    return false;
  }
  else if (millis() - lastAttemptTime > requestInterval)
  {
    makeHttpRequest("/private/followedBy.txt");

    Serial.println("making HTTP request to followed by cache file");
    return false;
  }
  else
  {
    return false;
  }
}

void blink(int blinkCount) //blink specified number of times
{
  for(int i = 0; i < blinkCount; i++)
  {
    for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5)
    { 
    // sets the value (range from 0 to 255):
      analogWrite(led, fadeValue);         
      // wait for 30 milliseconds to see the dimming effect    
      delay(40);                            
    } 

  // fade out from max to min in increments of 5 points:
    for(int fadeValue = 255 ; fadeValue >= 0; fadeValue -=5)
    { 
      // sets the value (range from 0 to 255):
      analogWrite(led, fadeValue);         
      // wait for 30 milliseconds to see the dimming effect    
      delay(40);                            
    } 
  //digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  //delay(3000);               // wait for a second
  //digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
  //delay(1000);               // wait for a second
  }
}

void makeHttpRequest(String url)
{
  // attempt to connect, and wait a millisecond:
  Serial.println("connecting to server...");
  if (client.connect(server, 80))
  {
    Serial.println("making HTTP request to " + url + " ...");
    // make HTTP GET request to twitter:
    client.println("GET " + url + " HTTP/1.1");
    client.println("Host:mysite.com");
    client.println("Connection:close");
    client.println();
  }
  else
  {
    Serial.println("Failure to connect.");
  }
  // note the time of this connect attempt:
  lastAttemptTime = millis();
}

void tweet(char givenTweet[])
{
  //start CLIENT code
  startTime = millis();
  char hashtag[] = "#hashtag";

  char tweet[170];
  int n=sprintf(tweet, "%s%s", givenTweet, hashtag);

  while((client.connect(server, 80) == false) &&
    ((millis() - startTime) < connectTimeout));


    if(client.connected())  // Success!
    {
      Serial.println("\nClient connected to server, ready to tweet!!!");

      if (twitter.post(tweet))
      {
        int status = twitter.wait(&Serial);
        if (status == 200) //this doesn't happen for some reason
        {
             Serial.println("\nTweet Successful: OK.\n");  
        }
        else
        {
            Serial.print("\nTweet Failed : code ");
            //Serial.println(status);
        }
      }
      else
      {
          int statusNum = twitter.wait(&Serial);
          Serial.println("\nConnection to Twitter failed.\n");
          if(statusNum==0) //should always be
            Serial.println("No status number returned.");
       }
      client.stop();
  }

}

Answer 1

几乎可以肯定你的内存已经用完了。请参阅http://playground.arduino.cc/Code/AvailableMemory