JSON parser
Kore provides a built-in JSON parser for your applications.
Index
- kore_json_init
- kore_json_cleanup
- kore_json_find_array
- kore_json_find_string
- kore_json_find_number
- kore_json_create_array
- kore_json_create_string
- kore_json_create_number
- kore_json_strerror
Examples
See the included example in the Kore source tree for an example on how to use this API.
kore_json_init
Synopsis
void kore_json_init(struct kore_json *json, const void *data, size_t len);
Description
Initializes a kore_json context. This must be called before any other function can be safely used.
Parameter | Description |
---|---|
json | A kore_json data structure. |
data | The JSON data to be parsed. |
len | The length of the JSON data to be parsed. |
Returns
Nothing
kore_json_cleanup
Synopsis
void kore_json_cleanup(struct kore_json *json);
Description
Cleanup the kore_json context and release all associated resources. This must be called when you no longer need the context.
Parameter | Description |
---|---|
json | A kore_json data structure. |
Returns
Nothing
kore_json_parse
Synopsis
int kore_json_parse(struct kore_json *json);
Description
Parse the JSON data that was set via kore_json_init.
Parameter | Description |
---|---|
json | A kore_json data structure. |
Returns
Returns KORE_RESULT_OK if parsing was successful or KORE_RESULT_ERROR if the parsing failed. If the parsing failed the json->error field holds the error code.
This error code can be translated to a human readable string via the kore_json_strerror() function.
kore_json_find_object
Synopsis
struct kore_json_item *kore_json_find_object(struct kore_json_item *item, const char *name);
Description
Find an object named name in the JSON root item.
Parameter | Description |
---|---|
item | A kore_json_item data structure representing the root. |
name | The name of the object to be found. |
Returns
A pointer to the JSON object as a kore_json_item data structure or NULL if the object was not found.
struct kore_json_item *object, *item;
if ((object = kore_json_find_object(json.root, "person")) == NULL)
return;
TAILQ_FOREACH(item, &object->data.items, list) {
printf("got a entry in the object of type %d\n", item->type);
}
kore_json_find_array
Synopsis
struct kore_json_item *kore_json_find_array(struct kore_json_item *item, const char *name);
Description
Find an array named name in the JSON root item.
Parameter | Description |
---|---|
item | A kore_json_item data structure representing the root. |
name | The name of the array to be found. |
Returns
A pointer to the JSON array as a kore_json_item data structure or NULL if the array was not found.
struct kore_json_item *items, *item;
if ((items = kore_json_find_array(json.root, "items")) == NULL)
return;
TAILQ_FOREACH(item, &items->data.items, list) {
printf("got a entry in the array of type %d\n", item->type);
}
kore_json_find_string
Synopsis
struct kore_json_item *kore_json_find_string(struct kore_json_item *item, const char *name);
Description
Find a string named name in the JSON root item.
Parameter | Description |
---|---|
item | A kore_json_item data structure representing the root. |
name | The name of the string to be found. |
Returns
A pointer to the JSON string as a kore_json_item data structure or NULL if the string was not found.
Example
struct kore_json_item *name;
name = kore_json_find_string(json.root, "name");
if (name != NULL)
printf("found name '%s'\n", name->data.string);
kore_json_find_number
Synopsis
struct kore_json_item *kore_json_find_number(struct kore_json_item *item, const char *name);
Description
Find a number named name in the JSON root item.
Parameter | Description |
---|---|
item | A kore_json_item data structure representing the root. |
name | The name of the number to be found. |
Returns
A pointer to the JSON number as a kore_json_item data structure or NULL if the number was not found.
Example
struct kore_json_item *price;
price = kore_json_find_number(json.root, "price");
if (price != NULL)
printf("found 'price' with value of %.0f\n", price->data.number);
kore_json_find_literal
Synopsis
struct kore_json_item *kore_json_find_literal(struct kore_json_item *item, const char *name);
Description
Find a literal named name in the JSON root item.
Parameter | Description |
---|---|
item | A kore_json_item data structure representing the root. |
name | The name of the literal to be found. |
Returns
A pointer to the JSON literal as a kore_json_item data structure or NULL if the literal was not found.
Possible values
KORE_JSON_TRUE - The JSON true value KORE_JSON_FALSE - The JSON false value KORE_JSON_NULL - The JSON null value
Example
struct kore_json_item *istrue;
istrue = kore_json_find_literal(json.root, "istrue");
if (istrue != NULL && istrue->data.literal == KORE_JSON_TRUE)
printf("istrue is set to true\n");
kore_json_create_object
Synopsis
struct kore_json_item *kore_json_create_object(struct kore_json_item *parent, const char *name);
Description
Creates a new JSON object under the given parent with the given name.
Parameter | Description |
---|---|
parent | A kore_json_item data structure representing the parent. |
name | The name of the object to be created. |
Parent
The parent parameter can be NULL if no parent is to be used.
Returns
A pointer to the JSON object as a kore_json_item data structure or NULL if something has failed.
Example
struct kore_json_item *person;
if ((person = kore_json_create_object(NULL, "person")) == NULL)
/* handle */
if (kore_json_create_number(person, "age", 34) == NULL)
/* handle */
kore_json_create_array
Synopsis
struct kore_json_item *kore_json_create_array(struct kore_json_item *parent, const char *name);
Description
Creates a new JSON array under the given parent with the given name.
Parameter | Description |
---|---|
parent | A kore_json_item data structure representing the parent. |
name | The name of the array to be created. |
Parent
The parent parameter can be NULL if no parent is to be used.
Returns
A pointer to the JSON array as a kore_json_item data structure or NULL if something has failed.
Example
struct kore_json_item *array;
if ((array = kore_json_create_array(NULL, "person")) == NULL)
/* handle */
if (kore_json_create_number(array, NULL, 34) == NULL)
/* handle */
if (kore_json_create_number(array, NULL, 27) == NULL)
/* handle */
kore_json_create_string
Synopsis
struct kore_json_item *kore_json_create_string(struct kore_json_item *parent, const char *name, const char *value);
Description
Creates a new JSON string under the given parent with the given name.
Parameter | Description |
---|---|
parent | A kore_json_item data structure representing the parent. |
name | The name of the string to be created. |
value | The value of the string. |
Parent
The parent parameter can be NULL if no parent is to be used.
Returns
A pointer to the JSON string as a kore_json_item data structure or NULL if something has failed.
Example
if (kore_json_create_string(parent, "person", "hacker") == NULL)
/* handle */
kore_json_create_number
Synopsis
struct kore_json_item *kore_json_create_number(struct kore_json_item *parent, const char *name, double value);
Description
Creates a new JSON number under the given parent with the given name.
Parameter | Description |
---|---|
parent | A kore_json_item data structure representing the parent. |
name | The name of the number to be created. |
value | The value of the number as a C double. |
Parent
The parent parameter can be NULL if no parent is to be used.
Returns
A pointer to the JSON number as a kore_json_item data structure or NULL if something has failed.
Example
if (kore_json_create_number(parent, "age", 34) == NULL)
/* handle */
kore_json_create_literal
Synopsis
struct kore_json_item *kore_json_create_literal(struct kore_json_item *parent, const char *name, int value);
Description
Creates a new JSON literal under the given parent with the given name.
Parameter | Description |
---|---|
parent | A kore_json_item data structure representing the parent. |
name | The name of the literal to be created. |
value | The value of the literal (see below). |
Parent
The parent parameter can be NULL if no parent is to be used.
Possible values
KORE_JSON_TRUE - The JSON true value KORE_JSON_FALSE - The JSON false value KORE_JSON_NULL - The JSON null value
Returns
A pointer to the JSON literal as a kore_json_item data structure or NULL if something has failed.
Example
if (kore_json_create_literal(parent, "istrue", KORE_JSON_FALSE) == NULL)
/* handle */
kore_json_errno
Synopsis
int kore_json_errno(void);
Description
Returns a the last error code that occurred.
Returns
The last error code that has occurred.
Example
kore_log(LOG_INFO, "parsing error '%d'", kore_json_errno());
kore_json_strerror
Synopsis
const char *kore_json_strerror(void);
Description
Returns a human readable string for last error that occurred.
Returns
A pointer to a human readable string that describes the error. This pointer should not be freed by the caller.
Example
kore_log(LOG_INFO, "parsing error '%s'", kore_json_strerror());