fix: dynotify: check curl retuen so when failed it will not crash

Before when no internet, curl error "curl_easy_perform() failed:
Couldn't resolve host name" will cause `json_tokener_parse(chunk.response)`
to crash the program with error "Segmentation fault (core dumped)". I
guess maybe because chunk.response is NULL because curl error not assign
value to it. Now I check return error code of curl to break the loop and
wait a minute to see if error gone and proceed forward. Maybe also check
chunk.response and json function error code somehow.

1 files changed, 11 insertions, 5 deletions

diff --git a/dynotify.c b/dynotify.c
index 3839e35..ec7cea8 100644
--- a/dynotify.c
+++ b/dynotify.c
@@ -1,5 +1,5 @@
 // curl:
-// man curl_easy_init CURLOPT_URL curl_easy_setopt CURLOPT_WRITEFUNCTION
+// man curl_easy_init CURLOPT_URL curl_easy_setopt CURLOPT_WRITEFUNCTION libcurl-errors curl_easy_strerror
 // https://curl.se/libcurl/
 // https://curl.se/libcurl/c/
 // https://curl.se/libcurl/c/libcurl-tutorial.html
@@ -79,8 +79,8 @@ static size_t cb(char *data, size_t size, size_t nmemb, void *clientp)
 
 int main (void)
 {
-	// https://curl.se/libcurl/c/libcurl-errors.html
-	//CURLcode res;
+	// man libcurl-errors
+	CURLcode res;
 	// `man curl_easy_init`: "It is encouraged to reuse easy handles for repeated transfers.", so I choose to reuse it
 	CURL *curl = curl_easy_init();
 	NotifyNotification *n;
@@ -100,8 +100,14 @@ int main (void)
 				curl_easy_setopt(curl, CURLOPT_URL, url);
 				curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, cb);
 				curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
-				//res = curl_easy_perform(curl);
-				curl_easy_perform(curl);
+				res = curl_easy_perform(curl);
+				// man curl_easy_strerror
+				if(res != CURLE_OK)
+				{
+					fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
+					free(chunk.response);
+					break;
+				}
 				//printf("%s\n",chunk.response);
 
 				json_object *root;