Retrieve the public key

{
  "success": true,
  "key": {
    "algorithm": "Ed25519",
    "key_id": "ed25519_2b9bc7e214b1209f",
    "public_key": "3VNX3t2NIvzg37o1w-bjxJdJVFtgbfpR-_Q80u4U5tQ",
    "encoding": "base64url"
  },
  "request_id": "req_d9e278f6722a692a5dc3bbe8"
}

/* C11 entry point. Build with client_http.c include, yyjson0.13.0 and libcurl7.76+.
 * Run request public-key; expected JSON, exit0 success/1 rejection/2 unavailable. */
#include "client_http.c"
int main(int argc,char **argv){return kdpika_example_main(argc,argv);}

/* Purpose: shared native libcurl transport for C11 and C++17 Sandbox examples.
 * Requires libcurl7.76+, yyjson0.13.0. Build commands are in the sample README.
 * Run request public-key. JSON stdout; exit0 success/1 rejection/2 setup/transport.
 * Credentials/body: KDP_* environment. Private terminal only; output may contain secrets.
 * Transport inspection only: verify signed state and policy before authorizing access.
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <curl/curl.h>
#include "yyjson.h"
static const char *kdp_contract="{\"public-key\":{\"method\":\"GET\",\"path\":\"/public-key\",\"auth\":\"public\"},\"activate\":{\"method\":\"POST\",\"path\":\"/licenses/activate\",\"auth\":\"publicApp\"},\"validate\":{\"method\":\"POST\",\"path\":\"/licenses/validate\",\"auth\":\"activation\"},\"deactivate\":{\"method\":\"POST\",\"path\":\"/licenses/deactivate\",\"auth\":\"activation\"}}";
typedef struct {char *data;size_t size;} kdp_buffer;
static size_t kdp_receive(char *data,size_t size,size_t count,void *context){
    kdp_buffer *b=(kdp_buffer *)context;
    if(size && count>SIZE_MAX/size)return 0;
    size_t n=size*count;if(n>1048576-b->size)return 0;
    char *p=(char *)realloc(b->data,b->size+n+1);if(!p)return 0;
    b->data=p;memcpy(p+b->size,data,n);b->size+=n;p[b->size]=0;return n;
}
static const char *kdp_env(const char *name){const char *v=getenv(name);return v?v:"";}
static const char *kdp_required(const char *name){const char *v=kdp_env(name);return *v&&!strchr(v,'\r')&&!strchr(v,'\n')?v:NULL;}
static int kdp_header(struct curl_slist **headers,const char *name,const char *value){
    if(!value)return 0;size_t n=strlen(name)+strlen(value)+3;char *line=(char *)malloc(n);if(!line)return 0;
    snprintf(line,n,"%s: %s",name,value);struct curl_slist *next=curl_slist_append(*headers,line);free(line);
    if(!next)return 0;*headers=next;return 1;
}
static int kdpika_example_main(int argc,char **argv){
    int code=2;CURL *curl=NULL;CURLU *url=NULL;struct curl_slist *headers=NULL;
    yyjson_doc *ops=NULL,*bodydoc=NULL,*result=NULL;char *scheme=NULL,*host=NULL,*path=NULL,*part=NULL,*target=NULL;
    kdp_buffer buffer={NULL,0};const char *base=kdp_env("KDP_BASE_URL"),*body=kdp_env("KDP_BODY_JSON");
    const char *method=NULL,*route=NULL,*auth=NULL;yyjson_val *op=NULL;long status=0;
    if(argc!=2)goto cleanup;
    if(!*base)base="https://licensing.kdpika.com/api/v1";
    if(!*body)body="{}";
    ops=yyjson_read(kdp_contract,strlen(kdp_contract),0);if(!ops)goto cleanup;
    op=yyjson_obj_get(yyjson_doc_get_root(ops),argv[1]);if(!op)goto cleanup;
    method=yyjson_get_str(yyjson_obj_get(op,"method"));route=yyjson_get_str(yyjson_obj_get(op,"path"));auth=yyjson_get_str(yyjson_obj_get(op,"auth"));
    if(!method||!route||!auth||curl_global_init(CURL_GLOBAL_DEFAULT)!=0)goto cleanup;
    url=curl_url();if(!url||curl_url_set(url,CURLUPART_URL,base,0)!=CURLUE_OK)goto cleanup;
    if(curl_url_get(url,CURLUPART_SCHEME,&scheme,0)||curl_url_get(url,CURLUPART_HOST,&host,0)||curl_url_get(url,CURLUPART_PATH,&path,0))goto cleanup;
    if(strcmp(path,"/api/v1")!=0)goto cleanup;
    if(strcmp(scheme,"https")!=0 && !(strcmp(scheme,"http")==0 && (!strcmp(host,"localhost")||!strcmp(host,"127.0.0.1")) && !strcmp(kdp_env("KDP_ALLOW_LOOPBACK"),"1")))goto cleanup;
    {CURLUPart forbidden[]={CURLUPART_USER,CURLUPART_PASSWORD,CURLUPART_QUERY,CURLUPART_FRAGMENT};
    for(size_t i=0;i<sizeof(forbidden)/sizeof(forbidden[0]);i++){if(curl_url_get(url,forbidden[i],&part,0)==CURLUE_OK)goto cleanup;}}
    target=(char *)malloc(strlen(base)+strlen(route)+1);if(!target)goto cleanup;strcpy(target,base);strcat(target,route);
    if(!kdp_header(&headers,"Accept","application/json")||!kdp_header(&headers,"User-Agent","KDPikaDocsExample/1.0 Native"))goto cleanup;
    if(!strcmp(auth,"publicApp")&&(!kdp_header(&headers,"X-App-ID",kdp_required("KDP_APP_ID"))||!kdp_header(&headers,"X-Environment","SANDBOX")))goto cleanup;
    if(!strcmp(auth,"activation")){
        const char *token=kdp_required("KDP_ACTIVATION_TOKEN");if(!token)goto cleanup;
        char *bearer=(char *)malloc(strlen(token)+8);if(!bearer)goto cleanup;strcpy(bearer,"Bearer ");strcat(bearer,token);
        int ok=kdp_header(&headers,"Authorization",bearer);free(bearer);if(!ok)goto cleanup;
    }
    if(!strcmp(argv[1],"validate")&&!kdp_header(&headers,"X-Installation-ID",kdp_required("KDP_INSTALLATION_ID")))goto cleanup;
    curl=curl_easy_init();if(!curl)goto cleanup;
    curl_easy_setopt(curl,CURLOPT_URL,target);curl_easy_setopt(curl,CURLOPT_CUSTOMREQUEST,method);
    curl_easy_setopt(curl,CURLOPT_FOLLOWLOCATION,0L);curl_easy_setopt(curl,CURLOPT_CONNECTTIMEOUT,5L);curl_easy_setopt(curl,CURLOPT_TIMEOUT,15L);
    curl_easy_setopt(curl,CURLOPT_SSL_VERIFYPEER,1L);curl_easy_setopt(curl,CURLOPT_SSL_VERIFYHOST,2L);
    curl_easy_setopt(curl,CURLOPT_WRITEFUNCTION,kdp_receive);curl_easy_setopt(curl,CURLOPT_WRITEDATA,&buffer);
    if(!strcmp(method,"POST")){
        bodydoc=yyjson_read(body,strlen(body),0);if(!bodydoc||!yyjson_is_obj(yyjson_doc_get_root(bodydoc)))goto cleanup;
        if(!kdp_header(&headers,"Content-Type","application/json"))goto cleanup;
        curl_easy_setopt(curl,CURLOPT_POSTFIELDS,body);
    }
    curl_easy_setopt(curl,CURLOPT_HTTPHEADER,headers);if(curl_easy_perform(curl)!=CURLE_OK)goto cleanup;
    curl_easy_getinfo(curl,CURLINFO_RESPONSE_CODE,&status);
    result=yyjson_read(buffer.data,buffer.size,0);if(!result||!yyjson_is_obj(yyjson_doc_get_root(result)))goto cleanup;
    printf("%s\n",buffer.data);
    code=status>=200&&status<300&&yyjson_is_true(yyjson_obj_get(yyjson_doc_get_root(result),"success"))?0:1;
cleanup:
    if(code)fprintf(stderr,"Request rejected, unavailable or configuration invalid. Inspect JSON error.code/request_id when returned; do not blindly retry mutations.\n");
    if(curl)curl_easy_cleanup(curl);if(url)curl_url_cleanup(url);curl_slist_free_all(headers);
    curl_free(scheme);curl_free(host);curl_free(path);curl_free(part);free(target);free(buffer.data);
    yyjson_doc_free(ops);yyjson_doc_free(bodydoc);yyjson_doc_free(result);return code;
}