Parsing and Serializing JSON
- Aryn Wiebe
- Lianne So
Working with JSON data in Iguana is easy. You can parse, create, and serialize JSON data efficiently using the built-in json module. Below is a quick guide on how to manage JSON data in the Translator.
Parsing JSON:
To parse incoming JSON data, use the json.parse{} function. This will convert a JSON string into a Lua table, which can then be manipulated easily.
Try it out with this simple code snippet:
local jsonTemplate = [[
{
"firstname":"John",
"lastname":"Doe",
"birthdate":"1997-04-11",
"phone":"(905)343-2352"
}
]]
function main(Data)
-- parse JSON
local msg = json.parse{data=jsonTemplate}
local name = msg.firstname..' '..msg.lastname
trace(name)
end Use the annotations to view the lua table generated from the JSON string.
Generating and Serializing JSON:
To generate JSON, use json.serialize{} to serialize Lua tables into a JSON Object or Array.
First, you can create a Lua table, either by following a static template or dynamically based on available inbound data from a source system.
For example, take this sample HL7 message and use it as sample data to map to a lua table. For practice, create a simple VMD called adt.vmd file and import the ADT^A04 for HL7v2.3.
MSH|^~\&|SENDING_APP|SENDING_FACILITY|RECEIVING_APP|RECEIVING_FACILITY|20110613083617||ADT^A04|934576120|P|2.3||||
EVN|A04|20110613083617|||
PID|1||135769||Mouse^Mickey||19281118|M|||123 Main St.^^Lake Buena Vista^FL^32830||(407)939-1289|||||1719|99999999|||
PV1|1|O|||||7^Disney^Walt^^MD^^^^||Using a Predefined Template:
Typically, the JSON template values will start as empty strings or JSON NULLs, ready to be populated.
local jsonTemplate = [[
{
"firstname":"",
"lastname":"",
"birthdate":"",
"phone":""
}
]]
function main(Data)
-- parse JSON
local msg = json.parse{data=jsonTemplate}
-- map HL7 to Lua table
local msgIn = hl7.parse{vmd='adt.vmd', data=Data}
msg.firstname = msgIn.PID[5][2]:nodeValue()
msg.lastname = msgIn.PID[5][1]:nodeValue()
msg.birthdate = msgIn.PID[7]:nodeValue()
msg.phone = msgIn.PID[13][1]:nodeValue()
end Dynamic Generation:
Both methods will result in the same Lua table:
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