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Merge pull request #1404 from kamailio/json-transformation
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json: add transformation
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@miconda
miconda committed Jan 24, 2018
2 parents e62fa8f + 12f6992 commit 9d8e957
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Showing 6 changed files with 866 additions and 12 deletions.
26 changes: 26 additions & 0 deletions src/modules/json/doc/json_admin.xml
View file
Expand Up @@ -74,5 +74,31 @@ xlog("foo is $var(foo)");
</example>
</section>
</section>

<section>
<title>Transformations</title>
<para>You can use the transformation to extract values from the json structured pseudo-variables</para>
<itemizedlist>
<listitem>
<para>
<emphasis>json</emphasis>
</para>
<example>
<title>
<function>json.parse</function> usage
</title>
<programlisting format="linespecific">
...
# extract value of "Custom-Data" from $rb pseudo-variable and set it to $var(Custom-Data)
$var(Custom-Data) = $(rb{json.parse,Custom-Data});
if($var(Custom-Data) != $null) { xlog("L_INFO", "$ci|log|custom data: $var(Custom-Data) from Request: $rb");
}
...
</programlisting>
</example>
</listitem>
</itemizedlist>
</section>
</section>
</chapter>

283 changes: 283 additions & 0 deletions src/modules/json/json_funcs.c
View file
Expand Up @@ -76,3 +76,286 @@ int json_get_field(struct sip_msg* msg, char* json, char* field, char* dst)
json_object_put(j);
return ret;
}

#define json_foreach_key(obj, key) \
char *key; \
struct lh_entry *entry##key; \
struct lh_entry *entry_next##key = NULL; \
for(entry##key = json_object_get_object(obj)->head; \
(entry##key ? (key = (char *)entry##key->k, \
entry_next##key = entry##key->next, entry##key) \
: 0); \
entry##key = entry_next##key)


static str json_pv_str_empty = {"", 0};

char **str_split(char *a_str, const char a_delim)
{
char **result = 0;
size_t count = 0;
char *tmp = a_str;
char *last_comma = 0;
char delim[2];
delim[0] = a_delim;
delim[1] = 0;
int len = 0;

/* Count how many elements will be extracted. */
while(*tmp) {
if(a_delim == *tmp) {
count++;
last_comma = tmp;
}
tmp++;
}

/* Add space for trailing token. */
count += last_comma < (a_str + strlen(a_str) - 1);

/* Add space for terminating null string so caller
knows where the list of returned strings ends. */
count++;

result = pkg_malloc(sizeof(char *) * count);

if(result) {
size_t idx = 0;
char *token = strtok(a_str, delim);

while(token) {
assert(idx < count);
len = strlen(token);
char *ptr = pkg_malloc((len + 1) * sizeof(char));
*(result + idx) = ptr;
memcpy(ptr, token, len);
ptr[len] = '\0';
int i = 0;
while(i < len) {
if(ptr[i] == tr_json_escape_char)
ptr[i] = '.';
i++;
}
token = strtok(0, delim);
idx++;
}
assert(idx == count - 1);
*(result + idx) = 0;
}

return result;
}

struct json_object *tr_json_get_field_object(str *json, str *field)
{
char **tokens;
char *dup;
char f1[25], f2[25]; //, f3[25];
int i;

dup = pkg_malloc(json->len + 1);
memcpy(dup, json->s, json->len);
dup[json->len] = '\0';
struct json_object *j = json_tokener_parse(dup);
pkg_free(dup);

if(is_error(j)) {
LM_ERR("empty or invalid JSON\n");
return NULL;
}

struct json_object *jtree = NULL;
struct json_object *ret = NULL;

LM_DBG("getting json %.*s\n", field->len, field->s);

dup = pkg_malloc(field->len + 1);
memcpy(dup, field->s, field->len);
dup[field->len] = '\0';
tokens = str_split(dup, '.');
pkg_free(dup);

if(tokens) {
jtree = j;
for(i = 0; *(tokens + i); i++) {
if(jtree != NULL) {
str field = str_init(*(tokens + i));
// check for idx []
int sresult = sscanf(field.s, "%[^[][%[^]]]", f1, f2); //, f3);
LM_DBG("CHECK IDX %d - %s , %s, %s\n", sresult, field.s, f1,
(sresult > 1 ? f2 : "(null)"));

jtree = json_get_object(jtree, f1);
if(jtree != NULL) {
char *value = (char *)json_object_get_string(jtree);
LM_DBG("JTREE OK %s\n", value);
}
if(jtree != NULL && sresult > 1
&& json_object_is_type(jtree, json_type_array)) {
int idx = atoi(f2);
jtree = json_object_array_get_idx(jtree, idx);
if(jtree != NULL) {
char *value = (char *)json_object_get_string(jtree);
LM_DBG("JTREE IDX OK %s\n", value);
}
}
}
pkg_free(*(tokens + i));
}
pkg_free(tokens);
}


if(jtree != NULL)
ret = json_object_get(jtree);

json_object_put(j);

return ret;
}


int tr_json_get_field_ex(str *json, str *field, pv_value_p dst_val)
{
struct json_object *jtree = tr_json_get_field_object(json, field);


if(jtree != NULL) {
char *value = (char *)json_object_get_string(jtree);
int len = strlen(value);
dst_val->rs.s = pkg_malloc(len + 1);
memcpy(dst_val->rs.s, value, len);
dst_val->rs.s[len] = '\0';
dst_val->rs.len = len;
dst_val->flags = PV_VAL_STR | PV_VAL_PKG;
dst_val->ri = 0;
json_object_put(jtree);
} else {
dst_val->flags = PV_VAL_NULL;
dst_val->rs = json_pv_str_empty;
dst_val->ri = 0;
}
return 1;
}


int tr_json_get_field(struct sip_msg *msg, char *json, char *field, char *dst)
{
str json_s;
str field_s;
pv_spec_t *dst_pv;
pv_value_t dst_val;

if(fixup_get_svalue(msg, (gparam_p)json, &json_s) != 0) {
LM_ERR("cannot get json string value\n");
return -1;
}

if(fixup_get_svalue(msg, (gparam_p)field, &field_s) != 0) {
LM_ERR("cannot get field string value\n");
return -1;
}

if(tr_json_get_field_ex(&json_s, &field_s, &dst_val) != 1)
return -1;

dst_pv = (pv_spec_t *)dst;
dst_pv->setf(msg, &dst_pv->pvp, (int)EQ_T, &dst_val);
if(dst_val.flags & PV_VAL_PKG) {
pkg_free(dst_val.rs.s);
} else if(dst_val.flags & PV_VAL_SHM) {
shm_free(dst_val.rs.s);
}

return 1;
}

struct json_object *json_parse(const char *str)
{
struct json_tokener *tok;
struct json_object *obj;

tok = json_tokener_new();
if(!tok) {
LM_ERR("Error parsing json: could not allocate tokener\n");
return NULL;
}

obj = json_tokener_parse_ex(tok, str, -1);
if(tok->err != json_tokener_success) {
LM_ERR("Error parsing json: %s\n", json_tokener_error_desc(tok->err));
LM_ERR("%s\n", str);
if(obj != NULL) {
json_object_put(obj);
}
obj = NULL;
}

json_tokener_free(tok);
return obj;
}

struct json_object *json_get_object(
struct json_object *jso, const char *key)
{
struct json_object *result = NULL;
json_object_object_get_ex(jso, key, &result);
return result;
}

int tr_json_get_keys(struct sip_msg *msg, char *json, char *field, char *dst)
{
str json_s;
str field_s;
int_str keys_avp_name;
unsigned short keys_avp_type;
pv_spec_t *avp_spec;

if(fixup_get_svalue(msg, (gparam_p)json, &json_s) != 0) {
LM_ERR("cannot get json string value\n");
return -1;
}

if(fixup_get_svalue(msg, (gparam_p)field, &field_s) != 0) {
LM_ERR("cannot get field string value\n");
return -1;
}

if(dst == NULL) {
LM_ERR("avp spec is null\n");
return -1;
}

avp_spec = (pv_spec_t *)dst;

if(avp_spec->type != PVT_AVP) {
LM_ERR("invalid avp spec\n");
return -1;
}

if(pv_get_avp_name(0, &avp_spec->pvp, &keys_avp_name, &keys_avp_type)
!= 0) {
LM_ERR("invalid AVP definition\n");
return -1;
}

struct json_object *jtree = tr_json_get_field_object(&json_s, &field_s);

if(jtree != NULL) {
json_foreach_key(jtree, k)
{
LM_DBG("ITERATING KEY %s\n", k);
int_str v1;
v1.s.s = k;
v1.s.len = strlen(k);
if(add_avp(AVP_VAL_STR | keys_avp_type, keys_avp_name, v1) < 0) {
LM_ERR("failed to create AVP\n");
json_object_put(jtree);
return -1;
}
}
json_object_put(jtree);
}

return 1;
}
27 changes: 27 additions & 0 deletions src/modules/json/json_funcs.h
View file
Expand Up @@ -25,7 +25,34 @@
#define _JSON_FUNCS_H_

#include "../../core/parser/msg_parser.h"
#include <json.h>

int json_get_field(struct sip_msg* msg, char* json, char* field, char* dst);

#define json_extract_field(json_name, field) \
do { \
struct json_object *obj = json_get_object(json_obj, json_name); \
field.s = (char *)json_object_get_string(obj); \
if(field.s == NULL) { \
LM_DBG("Json-c error - failed to extract field [%s]\n", \
json_name); \
field.s = ""; \
} else { \
field.len = strlen(field.s); \
} \
LM_DBG("%s: [%s]\n", json_name, field.s ? field.s : "Empty"); \
} while(0);


extern char tr_json_escape_char;
extern str json_event_key;
extern str json_event_sub_key;

int tr_json_get_field(struct sip_msg *msg, char *json, char *field, char *dst);
int tr_json_get_keys(struct sip_msg *msg, char *json, char *field, char *dst);

struct json_object *json_parse(const char *str);
struct json_object *json_get_object(
struct json_object *jso, const char *key);

#endif

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