OAuth part

The minimum to pass all authentications and arrive at the embedded app
index. This library is to be used with shopify-app-template-c for now,
as it assumes the existence of shopify.app.toml in the parent directory,
and index.html in the frontend directory.

1 files changed, 46 insertions, 0 deletions

diff --git a/request.h b/request.h
new file mode 100644
index 0000000..7c8fe99
--- /dev/null
+++ b/request.h
@@ -0,0 +1,46 @@
+#include <curl/curl.h>
+
+#define TOKEN_URL "https://%s/oauth/access_token"
+#define TOKEN_URL_LEN strlen(TOKEN_URL) - strlen("%s")
+
+#define TOKEN_POST "client_id=%s&client_secret=%s&code=%s"
+#define TOKEN_POST_LEN strlen(TOKEN_POST) - strlen("%s") * 3
+
+static inline void request_init()
+{
+	curl_global_init(CURL_GLOBAL_DEFAULT);
+}
+
+static size_t append(char *data, size_t size, size_t nmemb, char **tok)
+{
+	size_t realsize = size * nmemb;
+	size_t tok_len = *tok ? strlen(*tok) : 0;
+	*tok = realloc(*tok, tok_len + realsize + 1);
+	strlcpy(&(*tok)[tok_len], data, realsize + 1);
+	return realsize;
+}
+
+static inline void request_token(const char *host, const char *key,
+		const char *secret_key, const char *code, char **tok)
+{
+	CURL *curl = curl_easy_init();
+	char url[TOKEN_URL_LEN + strlen(host) + 1];
+	sprintf(url, TOKEN_URL, host);
+	curl_easy_setopt(curl, CURLOPT_URL, url);
+	char post[TOKEN_POST_LEN + strlen(key) + strlen(secret_key)
+		+ strlen(code) + 1];
+	sprintf(post, TOKEN_POST, key, secret_key, code);
+	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, post);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, tok);
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, append);
+#ifdef DEBUG
+	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
+#endif
+	curl_easy_perform(curl);
+	curl_easy_cleanup(curl);
+}
+
+static inline void request_cleanup()
+{
+	curl_global_cleanup();
+}