implement check payment API client

1 files changed, 86 insertions, 0 deletions

diff --git a/src/lib/merchant_api_common.c b/src/lib/merchant_api_common.c
index 05e2637a..12bc81d4 100644
--- a/src/lib/merchant_api_common.c
+++ b/src/lib/merchant_api_common.c
@@ -20,6 +20,7 @@
  * @author Christian Grothoff
  */
 #include "platform.h"
+#include <curl/curl.h>
 #include <gnunet/gnunet_util_lib.h>
 
 
@@ -47,4 +48,89 @@ MAH_path_to_url_ (const char *base_url,
   return url;
 }
 
+
+/**
+ * Concatenate two strings and grow the first buffer (of size n)
+ * if necessary.
+ */
+#define STR_CAT_GROW(s, p, n) do { \
+    for (; strlen (s) + strlen (p) >= n; (n) = (n) * 2); \
+    (s) = GNUNET_realloc ((s), (n)); \
+    GNUNET_assert (NULL != (s)); \
+    strncat (s, p, n); \
+  } while (0)
+
+
+/**
+ * Make an absolute URL with query parameters.
+ *
+ * @param base_url absolute base URL to use
+ * @param path path of the url
+ * @param ... NULL-terminated key-value pairs (char *) for query parameters
+ * @returns the URL, must be freed with #GNUNET_free
+ */
+char *
+MAH_make_url (const char *base_url,
+              const char *path,
+              ...)
+{
+  static CURL *curl = NULL;
+  if (NULL == curl)
+  {
+    curl = curl_easy_init();
+    GNUNET_assert (NULL != curl);
+  }
+
+  size_t n = 256;
+  char *res = GNUNET_malloc (n);
+
+  GNUNET_assert (NULL != res);
+
+  STR_CAT_GROW (res, base_url, n);
+
+  if ( ('/' == path[0]) &&
+       (0 < strlen (base_url)) &&
+       ('/' == base_url[strlen (base_url) - 1]) )
+  {
+   /* avoid generating URL with "//" from concat */
+    path++;
+  }
+  else if ( ('/' != path[0]) && 
+            ('/' != base_url[strlen (base_url) - 1]))
+  {
+    /* put '/' between path and base URL if necessary */
+    STR_CAT_GROW (res, "/", n);
+  }
+
+  STR_CAT_GROW (res, path, n);
+
+  va_list args;
+  va_start (args, path);
+
+  unsigned int iparam = 0;
+
+  while (1) {
+    char *key = va_arg (args, char *);
+    if (NULL == key)
+      break;
+    char *value = va_arg (args, char *);
+    if (NULL == value)
+      continue;
+    if (0 == iparam)
+      STR_CAT_GROW (res, "?", n);
+    else
+      STR_CAT_GROW (res, "&", n);
+    iparam++;
+    char *urlencoded_value = curl_easy_escape (curl, value, strlen (value));
+    STR_CAT_GROW (res, key, n);
+    STR_CAT_GROW (res, "=", n);
+    STR_CAT_GROW (res, urlencoded_value, n);
+    curl_free (urlencoded_value);
+  }
+
+  va_end (args);
+
+  return res;
+}
+
 /* end of merchant_api_common.c */