Add evhttp_parse_query_str_flags()

And a set of flags:
- EVHTTP_URI_QUERY_LAST
- EVHTTP_URI_QUERY_NONCONFORMANT

Fixes: #15

http.c

@@ -3216,7 +3216,7 @@ evhttp_uridecode(const char *uri, int decode_plus, size_t *size_out)
 
 static int
 evhttp_parse_query_impl(const char *str, struct evkeyvalq *headers,
-    int is_whole_uri)
+    int is_whole_uri, unsigned flags)
 {
 	char *line=NULL;
 	char *argument;
@@ -3254,8 +3254,14 @@ evhttp_parse_query_impl(const char *str, struct evkeyvalq *headers,
 
 		value = argument;
 		key = strsep(&value, "=");
-		if (value == NULL || *key == '\0') {
-			goto error;
+		if (flags & EVHTTP_URI_QUERY_NONCONFORMANT) {
+			if (value == NULL)
+				value = "";
+			if (*key == '\0')
+				continue;
+		} else {
+			if (value == NULL || *key == '\0')
+				goto error;
 		}
 
 		if ((decoded_value = mm_malloc(strlen(value) + 1)) == NULL) {
@@ -3265,6 +3271,8 @@ evhttp_parse_query_impl(const char *str, struct evkeyvalq *headers,
 		evhttp_decode_uri_internal(value, strlen(value),
 		    decoded_value, 1 /*always_decode_plus*/);
 		event_debug(("Query Param: %s -> %s\n", key, decoded_value));
+		if (flags & EVHTTP_URI_QUERY_LAST_VAL)
+			evhttp_remove_header(headers, key);
 		evhttp_add_header_internal(headers, key, decoded_value);
 		mm_free(decoded_value);
 	}
@@ -3284,12 +3292,17 @@ done:
 int
 evhttp_parse_query(const char *uri, struct evkeyvalq *headers)
 {
-	return evhttp_parse_query_impl(uri, headers, 1);
+	return evhttp_parse_query_impl(uri, headers, 1, 0);
 }
 int
 evhttp_parse_query_str(const char *uri, struct evkeyvalq *headers)
 {
-	return evhttp_parse_query_impl(uri, headers, 0);
+	return evhttp_parse_query_impl(uri, headers, 0, 0);
+}
+int
+evhttp_parse_query_str_flags(const char *uri, struct evkeyvalq *headers, unsigned flags)
+{
+	return evhttp_parse_query_impl(uri, headers, 0, flags);
 }
 
 static struct evhttp_cb *

include/event2/http.h

@@ -1004,6 +1004,33 @@ char *evhttp_uridecode(const char *uri, int decode_plus,
 EVENT2_EXPORT_SYMBOL
 int evhttp_parse_query(const char *uri, struct evkeyvalq *headers);
 
+/** @see evhttp_parse_query_str_flags() */
+EVENT2_EXPORT_SYMBOL
+int evhttp_parse_query_str(const char *uri, struct evkeyvalq *headers);
+
+/** Tolerate queries that are not standard conformant.
+ *
+ * Here are some examples:
+ *
+ * - test=123&test2
+ *   with with this flag test2 will be present in the output headers
+ *
+ * - test=123&&test2=1
+ *   will parse the query with this flag
+ *
+ * - test=123&=456&test2=1
+ *   will parse the queyr with this flag, however there won't be empty key
+ *   present
+ */
+#define EVHTTP_URI_QUERY_NONCONFORMANT 0x01
+/** Prefer last value over the first from query args
+ *
+ * Example: test=123&test=456
+ * Without: test=123
+ * With   : test=456
+ */
+#define EVHTTP_URI_QUERY_LAST_VAL 0x02
+
 /**
    Helper function to parse out arguments from the query portion of an
    HTTP URI.
@@ -1019,10 +1046,11 @@ int evhttp_parse_query(const char *uri, struct evkeyvalq *headers);
 
    @param query_parse the query portion of the URI
    @param headers the head of the evkeyval queue
+   @param flags one or more of EVHTTP_URI_QUERY_*
    @return 0 on success, -1 on failure
  */
 EVENT2_EXPORT_SYMBOL
-int evhttp_parse_query_str(const char *uri, struct evkeyvalq *headers);
+int evhttp_parse_query_str_flags(const char *uri, struct evkeyvalq *headers, unsigned flags);
 
 /**
  * Escape HTML character entities in a string.

test/regress_http.c

@@ -2517,6 +2517,62 @@ http_parse_query_str_test(void *ptr)
 	tt_int_op(r, ==, 0);
 	evhttp_clear_headers(&headers);
 
+end:
+	evhttp_clear_headers(&headers);
+}
+static void
+http_parse_query_str_flags_test(void *ptr)
+{
+	struct evkeyvalq headers;
+	int r;
+
+	TAILQ_INIT(&headers);
+
+	/** ~EVHTTP_URI_QUERY_LAST_VAL */
+	r = evhttp_parse_query_str_flags("q=test&q=test2", &headers, 0);
+	tt_want(validate_header(&headers, "q", "test") == 0);
+	tt_int_op(r, ==, 0);
+	evhttp_clear_headers(&headers);
+
+	/** EVHTTP_URI_QUERY_LAST_VAL */
+	r = evhttp_parse_query_str_flags("q=test&q=test2", &headers, EVHTTP_URI_QUERY_LAST_VAL);
+	tt_want(validate_header(&headers, "q", "test2") == 0);
+	tt_int_op(r, ==, 0);
+	evhttp_clear_headers(&headers);
+
+	/** ~EVHTTP_URI_QUERY_NONCONFORMANT */
+	r = evhttp_parse_query_str_flags("q=test&q2", &headers, 0);
+	tt_int_op(r, ==, -1);
+	evhttp_clear_headers(&headers);
+
+	r = evhttp_parse_query_str_flags("q=test&&q2=test2", &headers, 0);
+	tt_int_op(r, ==, -1);
+	evhttp_clear_headers(&headers);
+
+	r = evhttp_parse_query_str_flags("q=test&=1&q2=test2", &headers, 0);
+	tt_int_op(r, ==, -1);
+	evhttp_clear_headers(&headers);
+
+	/** EVHTTP_URI_QUERY_NONCONFORMANT */
+	r = evhttp_parse_query_str_flags("q=test&q2", &headers, EVHTTP_URI_QUERY_NONCONFORMANT);
+	tt_want(validate_header(&headers, "q", "test") == 0);
+	tt_want(validate_header(&headers, "q2", "") == 0);
+	tt_int_op(r, ==, 0);
+	evhttp_clear_headers(&headers);
+
+	r = evhttp_parse_query_str_flags("q=test&&q2=test2", &headers, EVHTTP_URI_QUERY_NONCONFORMANT);
+	tt_want(validate_header(&headers, "q", "test") == 0);
+	tt_want(validate_header(&headers, "q2", "test2") == 0);
+	tt_int_op(r, ==, 0);
+	evhttp_clear_headers(&headers);
+
+	r = evhttp_parse_query_str_flags("q=test&=1&q2=test2", &headers, EVHTTP_URI_QUERY_NONCONFORMANT);
+	tt_want(validate_header(&headers, "q", "test") == 0);
+	tt_want(validate_header(&headers, "q2", "test2") == 0);
+	tt_int_op(r, ==, 0);
+	evhttp_clear_headers(&headers);
+
+
 end:
 	evhttp_clear_headers(&headers);
 }
@@ -4826,6 +4882,7 @@ struct testcase_t http_testcases[] = {
 	{ "bad_headers", http_bad_header_test, 0, NULL, NULL },
 	{ "parse_query", http_parse_query_test, 0, NULL, NULL },
 	{ "parse_query_str", http_parse_query_str_test, 0, NULL, NULL },
+	{ "parse_query_str_flags", http_parse_query_str_flags_test, 0, NULL, NULL },
 	{ "parse_uri", http_parse_uri_test, 0, NULL, NULL },
 	{ "parse_uri_nc", http_parse_uri_test, 0, &basic_setup, (void*)"nc" },
 	{ "uriencode", http_uriencode_test, 0, NULL, NULL },