Faster way to parse a HTTP response in Arduino

Question

I send a GET http request to a server and get following data back.

HTTP/1.1 200 
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: 2018年11月16日 16:30:05 GMT
Connection: close
35
{
 "uuid" : "13b29524-7e12-48fb-bbf9-4396aefff45d"
}
0

with the following code I get the header info and the body.

void parseResponse() {
 boolean headerEnd = false;
 byte lineCount = 0;
 String line;
 char endOfLine[] = "\r\n";
 while (1) {
 if (client.available()) {
 char inChar = client.read();
 if (!headerEnd && line.endsWith(endOfLine)) {
 // Just save the first then headers
 if (lineCount == 10) {
 headerEnd = true;
 } else {
 headers[lineCount] = line;
 line = "";
 lineCount++;
 }
 }
 if (line.endsWith("close")) {
 line = "";
 headerEnd = true;
 }
 if (headerEnd && line.endsWith("}")) {
 line.toCharArray(response, sizeof(response));
 client.stop();
 break;
 }
 line += inChar;
 }
 }
}

this thakes 60 - 70ms to parse. Is there a faster way to parse? I think that's slow, for so little text, in the world of AVRs.

• Shawn: That doesn't look like C...
• Elias Kosunen: The Arduino language is not C, but C++ with some non-standard extensions, such as boolean and byte for bool and unsigned char respectively. Please retag your question.
• Barmar: char lastChar = ""; should be char lastChar = '';. "" is a string, not a char.
• Barmar: But the lastChar variable is never used for anything, why do you keep assigning it?
• Mutus: @Barmer . Right, I have removed it.

Answer 1

there are nice functions inherited from Stream class

int parseResponse(char uuid[], int size) {
 if (!client.find("HTTP/1.1")) // skip HTTP/1.1
 return -1;
 int st = client.parseInt(); // parse status code
 int l = -1;
 if (st == 200 && client.find("\"uuid\" : \"")) {
 int l = client.readBytesUntil('"', uuid, size);
 uuid[l] = 0; // terminate the C string
 }
 return l;
}

• Mutus: Thanks for the note "client.readBytesUntil". I did not find that under Arduino Client. arduino.cc/en/Reference/ClientConstructor but there, arduino.cc/en/Reference/StreamReadBytesUntil. :S. It's now 20ms faster!