fix: bad error message on invalid URL scheme

Closes #243

Author: steve-chavez

src/errors.h

@@ -26,6 +26,21 @@
     list = new_list;                                                                               \
   } while (0)
 
+// curl_url_strerror is available starting from libcurl 7.80.0
+#define EREPORT_CURL_URL_SET(hdl, part, str, flags)                                                \
+  do {                                                                                             \
+    CURLUcode rc = curl_url_set(hdl, part, str, flags);                                            \
+    if (rc != CURLUE_OK)                                                                           \
+      ereport(ERROR, errmsg("invalid URL \"%s\": %s", str, curl_url_strerror(rc)));                \
+  } while (0)
+
+#define EREPORT_CURL_URL_GET(hdl, part, out, flags, value)                                         \
+  do {                                                                                             \
+    CURLUcode rc = curl_url_get(hdl, part, out, flags);                                            \
+    if (rc != CURLUE_OK)                                                                           \
+      ereport(ERROR, errmsg("failed to encode URL \"%s\": %s", value, curl_url_strerror(rc)));     \
+  } while (0)
+
 #define EREPORT_NULL_ATTR(tupIsNull, attr)                                                         \
   do {                                                                                             \
     if (tupIsNull) ereport(ERROR, errmsg("%s cannot be null", #attr));                             \

src/util.c

@@ -2,6 +2,7 @@
 
 #include "curl_prelude.h"
 
+#include "errors.h"
 #include "util.h"
 
 PG_FUNCTION_INFO_V1(_urlencode_string);
@@ -33,30 +34,20 @@ Datum _encode_url_with_params_array(PG_FUNCTION_ARGS) {
   bool          isnull;
   char         *param;
 
-  CURLU    *h  = curl_url();
-  CURLUcode rc = curl_url_set(h, CURLUPART_URL, url, 0);
-  if (rc != CURLUE_OK) {
-    // TODO: Use curl_url_strerror once released.
-    elog(ERROR, "%s", curl_easy_strerror((CURLcode)rc));
-  }
+  CURLU *h = curl_url();
+  EREPORT_CURL_URL_SET(h, CURLUPART_URL, url, 0);
 
   iterator = array_create_iterator(params, 0, NULL);
   while (array_iterate(iterator, &value, &isnull)) {
     if (isnull) continue;
 
     param = TextDatumGetCString(value);
-    rc    = curl_url_set(h, CURLUPART_QUERY, param, CURLU_APPENDQUERY);
-    if (rc != CURLUE_OK) {
-      elog(ERROR, "curl_url returned: %d", rc);
-    }
+    EREPORT_CURL_URL_SET(h, CURLUPART_QUERY, param, CURLU_APPENDQUERY);
     pfree(param);
   }
   array_free_iterator(iterator);
 
-  rc = curl_url_get(h, CURLUPART_URL, &full_url, 0);
-  if (rc != CURLUE_OK) {
-    elog(ERROR, "curl_url returned: %d", rc);
-  }
+  EREPORT_CURL_URL_GET(h, CURLUPART_URL, &full_url, 0, url);
 
   pfree(url);
   curl_url_cleanup(h);

test/test_http_errors.py

@@ -15,7 +15,20 @@ def test_get_bad_url(sess):
         """
         ))
 
-    assert r"resolve proxy name" in str(execinfo)
+    assert 'Unsupported URL scheme' in str(execinfo.value)
+
+
+def test_http_get_rejects_relative_url(sess):
+    """net.http_get with a correct error when given a relative url"""
+
+    with pytest.raises(Exception) as execinfo:
+        sess.execute(text(
+            """
+            select net.http_get('/malformed_url');
+        """
+        ))
+
+    assert 'invalid URL "/malformed_url"' in str(execinfo.value)
 
 
 def test_bad_post(sess):