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From eb2299a0897577048205e4d8a331168d82ce09d0 Mon Sep 17 00:00:00 2001
From: Noriko Hosoi <nhosoi@momo7.localdomain>
Date: Thu, 26 Jul 2018 17:18:38 -0700
Subject: [PATCH] Add a parameter skipempty to the json field type.
If skipempty is set as follows, empty json objects are dropped from
the parsed result.
%field_name:json:skipempty%
If any parameter other than "skipempty" is given ("bogus" in this
example), an error message "invalid flag for JSON parser: bogus"
is issued.
---
src/parser.c | 127 ++++++++++++++++++++++++++++++++++++++++++
src/parser.h | 2 +-
src/pdag.c | 2 +-
3 files changed, 129 insertions(+), 2 deletions(-)
diff --git a/src/parser.c b/src/parser.c
index 77407c6..6736c6f 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -2325,6 +2325,85 @@ PARSER_Parse(v2IPTables)
return r;
}
+/*
+ * Delete children of the given object if it has children and they are empty.
+ *
+ * return 0 if object is not empty
+ * return 1 if object is empty
+ * return < 0 if error
+ *
+ * Caller should do this:
+ * if (jsonSkipEmpty(obj) > 0) {
+ * json_object_put(obj);
+ * obj = NULL;
+ * }
+ * or otherwise not use obj if jsonSkipEmpty returns > 0.
+ */
+static int
+jsonSkipEmpty(struct json_object *__restrict__ json)
+{
+ int rc = 0;
+ struct json_object *val = NULL;
+
+ if(json == NULL) {
+ rc = 1;
+ goto finalize_it;
+ }
+
+ switch (json_object_get_type(json)) {
+ case json_type_string:
+ rc = json_object_get_string_len(json) == 0;
+ break;
+ case json_type_array:
+ {
+ int i;
+ int arrayLen = json_object_array_length(json);
+ for (i = 0 ; i < arrayLen ; ++i) {
+ val = json_object_array_get_idx(json, i);
+ if ((rc = jsonSkipEmpty(val)) > 0) {
+ /* delete the empty item and reset the index and arrayLen */
+ json_object_array_del_idx(json, i--);
+ arrayLen = json_object_array_length(json);
+ } else if (rc < 0) {
+ goto finalize_it;
+ }
+ }
+ rc = json_object_array_length(json) == 0;
+ break;
+ }
+ case json_type_object:
+ {
+ struct json_object_iterator it = json_object_iter_begin(json);
+ struct json_object_iterator itEnd = json_object_iter_end(json);
+ while (!json_object_iter_equal(&it, &itEnd)) {
+ val = json_object_iter_peek_value(&it);
+ if ((rc = jsonSkipEmpty(val)) > 0) {
+ json_object_object_del(json, json_object_iter_peek_name(&it));
+ } else if (rc < 0) {
+ goto finalize_it;
+ }
+ json_object_iter_next(&it);
+ }
+ rc = json_object_object_length(json) == 0;
+ }
+ case json_type_null:
+ case json_type_boolean:
+ case json_type_double:
+ case json_type_int:
+ default: break;
+ }
+finalize_it:
+ return rc;
+}
+
+/*
+ * Parameters for field type json
+ * skipempty - skips empty json objects.
+ * - %field_name:json:skipempty%
+ */
+struct data_JSON {
+ int skipempty;
+};
/**
* Parse JSON. This parser tries to find JSON data inside a message.
* If it finds valid JSON, it will extract it. Extra data after the
@@ -2340,6 +2419,7 @@ PARSER_Parse(v2IPTables)
PARSER_Parse(JSON)
const size_t i = *offs;
struct json_tokener *tokener = NULL;
+ struct data_JSON *const data = (struct data_JSON*) pdata;
if(npb->str[i] != '{' && npb->str[i] != ']') {
/* this can't be json, see RFC4627, Sect. 2
@@ -2368,6 +2448,20 @@ PARSER_Parse(JSON)
if(value == NULL) {
json_object_put(json);
} else {
+ if (data && data->skipempty) {
+ int rc = jsonSkipEmpty(json);
+ if (rc < 0) {
+ json_object_put(json);
+ FAIL(LN_WRONGPARSER);
+ } else if (rc > 0) {
+ /*
+ * json value is empty.
+ * E.g., {"message":""}, {"message":[]}, {"message":{}}
+ */
+ json_object_put(json);
+ FAIL(0);
+ }
+ }
*value = json;
}
@@ -2376,7 +2470,40 @@ PARSER_Parse(JSON)
json_tokener_free(tokener);
return r;
}
+PARSER_Construct(JSON)
+{
+ int r = 0;
+ struct json_object *ed;
+ struct data_JSON *data = NULL;
+ char *flag;
+ if(json == NULL)
+ goto done;
+
+ if(json_object_object_get_ex(json, "extradata", &ed) == 0) {
+ /* No JSON parameter */
+ goto done;
+ }
+ data = (struct data_JSON*) calloc(1, sizeof(struct data_JSON));
+ flag = json_object_get_string(ed);
+ if (strcasecmp(flag, "skipempty") == 0) {
+ data->skipempty = 1;
+ } else {
+ ln_errprintf(ctx, 0, "invalid flag for JSON parser: %s", flag);
+ r = LN_BADCONFIG;
+ goto done;
+ }
+ *pdata = data;
+done:
+ if(r != 0) {
+ free(data);
+ }
+ return r;
+}
+PARSER_Destruct(JSON)
+{
+ free(pdata);
+}
/* check if a char is valid inside a name of a NameValue list
* The set of valid characters may be extended if there is good
diff --git a/src/parser.h b/src/parser.h
index 38be62d..5b4a821 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -70,7 +70,7 @@ PARSERDEF_NO_DATA(Time24hr);
PARSERDEF_NO_DATA(Duration);
PARSERDEF_NO_DATA(IPv4);
PARSERDEF_NO_DATA(IPv6);
-PARSERDEF_NO_DATA(JSON);
+PARSERDEF(JSON);
PARSERDEF_NO_DATA(CEESyslog);
PARSERDEF_NO_DATA(v2IPTables);
PARSERDEF_NO_DATA(CiscoInterfaceSpec);
diff --git a/src/pdag.c b/src/pdag.c
index 0768e99..9feb755 100644
--- a/src/pdag.c
+++ b/src/pdag.c
@@ -90,7 +90,7 @@ static struct ln_parser_info parser_lookup_table[] = {
PARSER_ENTRY_NO_DATA("duration", Duration, 16),
PARSER_ENTRY_NO_DATA("cisco-interface-spec", CiscoInterfaceSpec, 4),
PARSER_ENTRY_NO_DATA("name-value-list", NameValue, 8),
- PARSER_ENTRY_NO_DATA("json", JSON, 4),
+ PARSER_ENTRY("json", JSON, 4),
PARSER_ENTRY_NO_DATA("cee-syslog", CEESyslog, 4),
PARSER_ENTRY_NO_DATA("mac48", MAC48, 16),
PARSER_ENTRY_NO_DATA("cef", CEF, 4),
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