我正在写一个arduino库来在网上发布http请求. 我正在使用http://arduino.cc/en/Tutorial/TextString的String类 当我在函数调用后引用我定义的字符串对象时,我的代码表现得很奇怪. 实际上,我试图获取
我正在使用http://arduino.cc/en/Tutorial/TextString的String类
当我在函数调用后引用我定义的字符串对象时,我的代码表现得很奇怪.
实际上,我试图获取我的GET请求的主体并从http GET请求的响应中删除http标头.
以下是描述：
方法调用：
String body;
if(pinger.Get(host,path,&body))
{
Serial.println("Modified String Outside :");
Serial.println(body);
Serial.println();
Serial.println("Modified String Outside Address");
Serial.println((int)&body);
}
产量
Modified String Outside : HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: text/html Content-Length: 113 Date: Wed, 13 Jan 2010 14:36:28 GMT <html> <head> <title>Ashish Sharma </title> </head> <body> Wed Jan 13 20:06:28 IST 2010 </body> </html> Modified String Outside Address 2273
方法描述：
bool Pinger::Get(String host, String path, String *response) {
bool connection = false;
bool status = false;
String post1 = "GET ";
post1 = post1.append(path);
post1 = post1.append(" HTTP/1.1");
String host1 = "Host: ";
host1 = host1.append(host);
for (int i = 0; i < 10; i++) {
if (client.connect()) {
client.println(post1);
client.println(host1);
client.println();
connection = true;
break;
}
}
int nlCnt = 0;
while (connection) {
if (client.available()) {
int c = client.read();
response->append((char) c);
if (c == 0x000A && nlCnt == 0) {
nlCnt++;
if (response->contains("200")) {
status = true;
continue;
} else {
client.stop();
client.flush();
break;
}
}
}
if (!client.connected()) {
client.stop();
connection = false;
}
}
response = &response->substring(response->indexOf("\n\r\n"),response->length());
Serial.println("Modified String: ");
Serial.println(*response);
Serial.println();
Serial.print("Modified String Address: ");
Serial.println((int)&response);
return status;
}
输出：
Modified String: Ø <html> <head> <title>Ashish Sharma </title> </head> <body> Wed Jan 13 20:06:28 IST 2010 </body> </html> Modified String Address: 2259
从示例中可以看出,字符串引用对象在Get方法中给出了正确的字符串,但是当Get方法返回时,字符串内容的引用会发生变化.
如果我理解你的代码,你可能会想要做这样的事情：*response = response->substring(response->indexOf("\n\r\n"),response->length());
代替
response = &response->substring(response->indexOf("\n\r\n"),response->length());
也可能没有必要传入指针(引用可能会使代码看起来更好).