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json-procs.tcl

Utility ad_procs for Tcl <-> JSON conversion. This is based on the tcllib json package written by Andreas Kupries, and later rewritten to parse via regular expressions by Thomas Maeder. The tcllib version suffers from generating Tcl structures from JSON strings with no type (JSON array or object) information. The resulting structures can't be converted back to JSON strings, you have to munge them with type information first. And the code making use the Tcl structure also needs to know whether each field is an object or array. It also depends on the DICT package or Tcl 8.5. This rewrite doesn't depend on DICT, declares procs using ad_proc (so the API will be picked up by our API browser), and is symmetrical (you can convert from JSON to the Tcl representation and back again). I've not renamed internal variables in the typical OpenACS style. I've placed these in the global util namespace for two reasons: 1. Don't want to clash with the tcllib json package in case someone else decides to use it. 2. Might put it in acs-tcl as part of the utility stuff someday. More information ... See http://www.json.org/ && http://www.ietf.org/rfc/rfc4627.txt Total rework of the code published with version number 1.0 by Thomas Maeder, Glue Software Engineering AG

Location:
packages/acs-tcl/tcl/json-procs.tcl
Created:
2010/04/09
Author:
Don Baccus
CVS Identification:
$Id: json-procs.tcl,v 1.11 2018/07/25 21:19:26 hectorr Exp $

Procedures in this file

Detailed information

util::json::array::create (public)

 util::json::array::create values

Construct a JSON object with the given values list

Parameters:
values

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::array::get_values (public)

 util::json::array::get_values item

Verify that the given Tcl structure is an object, and return its values list.

Parameters:
item

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::gen (public)

 util::json::gen value

Top-level procedure to generate a JSON string from its Tcl list representation.

Parameters:
value - A two-element object/array Tcl list.
Returns:
A valid JSON string.

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::indent (public)

 util::json::indent [ -simplify ] json

Indent a JSON string to make it more easily digestable by the human mind. This works best (by far) if the JSON string doesn't already contain newlines (as will be true of JSON strings generated by util::json::gen).

Switches:
-simplify (boolean) (optional)
If true, remove all fields that don't contribute to the structure of the object/array combination being described by the string.
Parameters:
json - The string to indent
Returns:
The beautifully indented, and optionally simplified, string

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::json_value_to_sql_value (public)

 util::json::json_value_to_sql_value value

While mysql happily treats false as 0, real SQL does not. And we need to protect against apostrophes in strings. And handle null. You get the idea.

Parameters:
value - A value from a parsed JSON string
Returns:
Something that works in Real SQL, not to be confused with MySQL. This includes not trying to insert '' into columns of type real, when "null" is meant (we mimic Oracle bindvar/PG bindvar emulation semantics). The Ilias RTE JavaScript returns '' rather than null for JS null variables.

Partial Call Graph (max 5 caller/called nodes):
%3 ns_dbquotevalue ns_dbquotevalue util::json::json_value_to_sql_value util::json::json_value_to_sql_value util::json::json_value_to_sql_value->ns_dbquotevalue

Testcases:
No testcase defined.

util::json::object::create (public)

 util::json::object::create values

Construct a JSON object with the given values list

Parameters:
values

Partial Call Graph (max 5 caller/called nodes):
%3 util::json::object::set_by_path util::json::object::set_by_path (public) util::json::object::create util::json::object::create util::json::object::set_by_path->util::json::object::create util::json::object::set_value util::json::object::set_value (public) util::json::object::set_value->util::json::object::create

Testcases:
No testcase defined.

util::json::object::get_value (public)

 util::json::object::get_value -object object -attribute attribute

Returns the value of an attribute in an object. If the attribute doesn't exist, an error will result.

Switches:
-object (required)
The JSON object which contains the attribute.
-attribute (required)
The attribute name.
Returns:
The attribute value or an error, if the attribute doesn't exist.

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::object::get_values (public)

 util::json::object::get_values item

Verify that the given Tcl structure is an object, and return its values list.

Parameters:
item

Partial Call Graph (max 5 caller/called nodes):
%3 util::json::object::get_value util::json::object::get_value (public) util::json::object::get_values util::json::object::get_values util::json::object::get_value->util::json::object::get_values util::json::object::set_by_path util::json::object::set_by_path (public) util::json::object::set_by_path->util::json::object::get_values util::json::object::set_value util::json::object::set_value (public) util::json::object::set_value->util::json::object::get_values

Testcases:
No testcase defined.

util::json::object::set_by_path (public)

 util::json::object::set_by_path -object object -path path -value value

This is an odd utility that mimics some odd code in the Ilias SCORM module, included here because it might be of more general use. Essentially we walk down an object tree structure using the "path" parameter. If we encounter a leaf on the way, we replace it with a new object node and continue. The last element of the path is interpreted as a leaf of the tree and is set to "value". Example: util::json::gen [util::json::object::set_by_path -object "" -path {a b c} -value 3] Result: {"a":{"b":{"c":3}}} Example: util::json::gen [util::json::object::set_by_path -object [util::json::object::create [list a [util::json::object::create [list d null]]]] -path {a b c} -value 3] Result: {"a":{"b":{"c":3},"d":null}} "a" is the top level object with two subnodes "b" and "d", with "b" having a subnode "c" of value 3, and "d" being a leaf of "a" with value "null".

Switches:
-object (required)
The object to add subnodes to.
-path (required)
The path through the tree with the last value being the name of a new or existing leaf.
-value (required)
The value to set the final leaf to.
Returns:
A new object with the new tree structure interwoven into it.

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::object::set_value (public)

 util::json::object::set_value -object object -attribute attribute \
    -value value

Set an attribute value in an object structure. If the attribute doesn't exist in the object, it's created.

Switches:
-object (required)
The object we want to set the value in.
-attribute (required)
The name of the attribute.
-value (required)
The value to set attribute to.
Returns:
A new object with the attribute/value pair.

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::parse (public)

 util::json::parse jsonText

Parse JSON text into a Tcl list.

Parameters:
jsonText - JSON text
Returns:
List containing the object represented by jsonText

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::sql_values_to_json_values (public)

 util::json::sql_values_to_json_values row

Converts empty values to "null", consistent with how oracle, mysql, and the nspostgres bindvar hack treats them.

Parameters:
row - A row (list) returned by a sql SELECT.
Returns:
A new list with empty strings converted to null.

Partial Call Graph (max 5 caller/called nodes):
%3

Testcases:
No testcase defined.

util::json::type_of (public)

 util::json::type_of item

Return the type of the item, "object" or "array"

Parameters:
item

Partial Call Graph (max 5 caller/called nodes):
%3 _ _ (public) util::json::type_of util::json::type_of util::json::type_of->_

Testcases:
No testcase defined.
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