CODEWITHSUNDEEP
c
Neha
Neha

Reputation: 23

extract number from http request

I want to extract some number from HTTP Get requests in C. for example if my HTTP request is like:

GET /getUIKVal?mdn=9860436150 HTTP/1.1
Host: api.end.point

I want number 9860436150 to be printed as output. I have already tried with sscanf() and atoi()

Upvotes: 1

Views: 351

Answers (2)

kiran Biradar
kiran Biradar

Reputation: 12742

You can simply use sscanf like below.

char* line = "GET /getUIKVal?mdn=9860436150 HTTP/1.1";
long long val ;

int ret = sscanf(line, "%*[^=]=%lld",&val);
printf("%lld\n", val) ;

Where %*[^=]= will read and discard the string until it reaches = and %ld will read actual number in val.

Upvotes: 1

Stephan Lechner
Stephan Lechner

Reputation: 35164

You could use strstr to identify marker mdn= and then either scan a number or a string. Note that for scanning the number you don't need to copy the respective contents; The code below shows how:

const char* content = "GET /getUIKVal?mdn=9860436150 HTTP/1.1";
const char* startOfNumber = strstr(content,"mdn=");
if (startOfNumber) {
   startOfNumber += strlen("mdn=");
   long number;
   if (scanf("%ld",&number)==1) {
      printf("the number is... %ld", number);
   } else {
      printf("no valid number after 'mdn='");      
   }
} else {
      printf("marker 'mdn=' not found.");      
}

I actually prefer the strstr-solution over a solution where scanf identifies both the marker and the number because it is hard to reason about syntax errors then.

Upvotes: 0

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