JSON and XML Parsing Library-阿里云帮助中心

The JSON and XML Parsing Library provides built-in functions for reading and writing structured data inside smart contracts on Alibaba Cloud Blockchain as a Service (BaaS). Use these functions to parse JSON or XML input, extract typed node values, insert data, and release the parser handle when done.

Function index

Function	Description
`property_parse`	Parse a JSON or XML string and return a handler
`property_destroy`	Release the handler returned by `property_parse`
`property_get_bool`	Read a `bool` node value
`property_get_int`	Read an `int` node value
`property_get_uint`	Read a `uint` node value
`property_get_string`	Read a `string` node value
`property_set_bool`	Write a `bool` node value
`property_set_int`	Write an `int` node value
`property_set_uint`	Write a `uint` node value
`property_set_string`	Write a `string` node value

Return value conventions

All functions share a consistent return value pattern:

Function group	`result` type	Success value	Failure value
`property_parse`	`uint`	Non-zero handler	—
`property_destroy`, `property_set_*`	`bool`	`true`	`false`
`property_get_*`	`int`	`1`	`0`

For property_get_* functions, always check result before using data. A result of 0 means the path was not found or the call failed.

Usage notes

Path format: The path parameter is a dot-separated string that locates a node in the parsed document. For example, to access {"order": {"price": 100}}, use path = "order.price". For XML, use the element tag name hierarchy in the same dot notation.

Handler lifecycle: Always call property_destroy after you finish reading or writing. This releases the memory allocated by property_parse.

property_parse

Parses a JSON or XML string and returns a handler used by all subsequent calls.

Syntax

property_parse(string property_value, int property_type) returns(uint result);

Request parameters

Name	Required	Type	Description
`property_value`	Yes	string	The data to parse, in JSON or XML format.
`property_type`	Yes	int	The format of `property_value`. `0` = JSON, `1` = XML.

Response parameters

Name	Required	Type	Description
`result`	Yes	uint	The handler for this parse session. Pass this value to all subsequent `property_get_`, `property_set_`, and `property_destroy` calls.

property_destroy

Releases the handler returned by property_parse and frees the associated memory.

Syntax

property_destroy(uint handler) returns(bool result);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.

Response parameters

Name	Required	Type	Description
`result`	Yes	bool	`true` if the handler was released successfully. `false` if the call failed.

property_get_bool

Reads a node of type bool from the parsed document.

Syntax

property_get_bool(uint handler, string path) returns(int result, bool data);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node (for example, `"user.active"`).

Response parameters

Name	Required	Type	Description
`result`	Yes	int	`1` if the node was found and read successfully. `0` if the call failed.
`data`	Yes	bool	The value of the node at `path`.

property_get_int

Reads a node of type int from the parsed document.

Syntax

property_get_int(uint handler, string path) returns(int result, int data);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node (for example, `"order.amount"`).

Response parameters

Name	Required	Type	Description
`result`	Yes	int	`1` if the node was found and read successfully. `0` if the call failed.
`data`	Yes	int	The value of the node at `path`.

property_get_uint

Reads a node of type uint from the parsed document.

Syntax

property_get_uint(uint handler, string path) returns(int result, uint data);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node (for example, `"token.balance"`).

Response parameters

Name	Required	Type	Description
`result`	Yes	int	`1` if the node was found and read successfully. `0` if the call failed.
`data`	Yes	uint	The value of the node at `path`.

property_get_string

Reads a node of type string from the parsed document.

Syntax

property_get_string(uint handler, string path) returns(int result, string memory data);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node (for example, `"product.name"`).

Response parameters

Name	Required	Type	Description
`result`	Yes	int	`1` if the node was found and read successfully. `0` if the call failed.
`data`	Yes	string memory	The value of the node at `path`.

property_set_bool

Creates data in JSON and XML, and inserts data of the bool type.

Syntax

property_set_bool(uint handler, string path, bool data) returns(bool result);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node.
`data`	Yes	bool	The value to set.

Response parameters

Name	Required	Type	Description
`result`	Yes	bool	`true` if the value was set successfully. `false` if the call failed.

property_set_int

Creates data in JSON and XML, and inserts data of the int type.

Syntax

property_set_int(uint handler, string path, int data) returns(bool result);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node.
`data`	Yes	int	The value to set.

Response parameters

Name	Required	Type	Description
`result`	Yes	bool	`true` if the value was set successfully. `false` if the call failed.

property_set_uint

Creates data in JSON and XML, and inserts data of the uint type.

Syntax

property_set_uint(uint handler, string path, uint data) returns(bool result);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node.
`data`	Yes	uint	The value to set.

Response parameters

Name	Required	Type	Description
`result`	Yes	bool	`true` if the value was set successfully. `false` if the call failed.

property_set_string

Creates data in JSON and XML, and inserts data of the string type.

Syntax

property_set_string(uint handler, string path, val data) returns(bool result);

Request parameters

Name	Required	Type	Description
`handler`	Yes	uint	The handler returned by `property_parse`.
`path`	Yes	string	Dot-separated path to the target node.
`data`	Yes	val	The value to set.

Response parameters

Name	Required	Type	Description
`result`	Yes	bool	`true` if the value was set successfully. `false` if the call failed.