Need help parsing..

Sato · 17 Feb 2023, 16:59

Hi,
I am not a C++ expert, so maybe someone on the Forum can help how to solve the Parse of the following

@init dev:OF21 Av. John XXI uuid:d3f1c986-16b3-4758-9724-51da22471f0c

How can I store the following characters in a variable1
OF21 Av. John XXI

as well as the following in a variable2
d3f1c986-16b3-4758-9724-51da22471f0c

Thanks
Best regards

kl3m3n · 17 Feb 2023, 18:36

@Sato Hi.

One option using STL:

#include <string>

static const std::string dev_token{"dev:"};
static const std::string uuid_token{"uuid:"};
    
auto dev_s = str.find(dev_token);
auto uuid_s = str.find(uuid_token);
    
if(dev_s != std::string::npos 
   && uuid_s != std::string::npos) {
     dev_s += dev_token.length();
     const auto dev_str = str.substr(dev_s, uuid_s - dev_s - 1); // -1 removes the trailing whitespace
        
     uuid_s += uuid_token.length();
     const auto uuid_str = str.substr(uuid_s, 36); // uuid is always 36 characters
        
     // dev_str and uuid_str are the desired payloads
}

NOTE: If you enable sending usr, this will not work as the usr payload is inserted between dev and uuid...

Best regards,
kl3m3n

Sato · 17 Feb 2023, 19:08

@kl3m3n
Thank you kl3m3n,

Unfortunately I not undestand the code, but it gives compile error

The @init dev: OF21 Av. John XXI uuid:d3f1c986-16b3-4758-9724-51da22471f0c is in the msg variable

I try
auto dev_s = msg.find("dev:");
auto uuid_s = msg.find("uuid:");
compile error: const class String has no member named 'find'

and that can't compile too
auto dev_s = str.find("dev:");
auto uuid_s = str.find("uuid:");
compile error: 'str' was not declared in this scope

NOTE: If you enable sending usr, this will not work as the usr payload is inserted between dev and uuid...
I know, on startup don´t needed, later during the programm starting i get the usr

Best regards

kl3m3n · 17 Feb 2023, 19:14

@Sato

str is your msg

You using Arduino right?

Try:

std::string str = std::string(msg.c_str());

and then use my code...

Although it seems unnecessary to convert between String and std::string... You can write the same code using Arduino String functions (using indexOf(), etc...):

https://www.arduino.cc/reference/en/language/variables/data-types/stringobject/

Regards,
kl3m3n

Sato · 17 Feb 2023, 19:32

@kl3m3n

Yes, I use Arduino
(using indexOf(), etc...):
That's how I was doing it, but I wasn't sure that the uuid length was fixed.

Your code compiles, but gives an error if you want to see the contents of dev_str and uuid_str in the serial monitor
no matching function for call to 'HardwareSerial::println(const std::__cxx11::basic_string<char>&)'

Best regards

kl3m3n · 17 Feb 2023, 19:51

@Sato Yes, because Serial.println requires String and not std::string...

Try

Serial.println(dev_str.c_str())

kl3m3n

Sato · 17 Feb 2023, 20:22

@kl3m3n,

I still don't understand your code, but I will try to learn. Compared to (using indexOf(), etc...) your code is more elegant, I will use it if you don't mind.

Your knowledge is impressive, you are still the best

Thanks
Regards