Answered check for existance of Json value before reading to temp-table

[Potish]

I am reading data from a json file into a temp-table provided by an external vendor. Some fields on the json file are not included every time. How do I check if a field exists on the json file before I attempt to read it. A simplified version of my code looks as follows

USING Progress.Json.ObjectModel.ObjectModelParser.
USING Progress.Json.ObjectModel.JsonArray.
USING Progress.Json.ObjectModel.JsonObject.

DEFINE VARIABLE oParser             AS ObjectModelParser NO-UNDO.
DEFINE VARIABLE oavailabilityArray  AS JsonArray         NO-UNDO.
DEFINE VARIABLE oavailabilityObject AS JsonObject        NO-UNDO.

define temp-table ttHAPIavailability like HAPIavailability.

oParser  = NEW ObjectModelParser().
oavailabilityObject = CAST(oParser:ParseFile("testfile.json"), JsonObject).

create ttHAPIavailability.
assign
    ttHAPIavailability.price = decimal(oavailabilityObject:GetCharacter("price"))
    ttHAPIavailability.currency = oavailabilityObject:GetCharacter("currency")
    ttHAPIavailability.additional_info = oavailabilityObject:GetCharacter("additional_info").

In this case 'additional_info' is not always passed so if I don't check prior to reading it I end up with the following error

Call to Progress.Json.ObjectModel.JsonObject:GetCharacter( ) failed. Property 'additional_info' was not found. (16058)

 

[TheMadDBA]

Add NO-ERROR to your assign or CATCH the errors.

Why not use READ-JSON on the temp-table instead? It handles all of that for you.

 

[mollyfud]

I haven't tried it myself, but there is a "HAS" method that is described as:
Returns a LOGICAL indicating if the JsonObject contains the named property.

Takes a character input of the property name. Wonder if you could check if the property exists and if it does, setting it.

Hope this helps.
TIA
Molly

 

[Potish]

Quick update. Adding the NO-ERROR worked for now.

The reason I asked about this option is because the vendor I am working sometimes nests the json in a way that READ-JSON is not able to support so I wanted to have the information for those cases. Where I can I always use the READ-JSON.

I will look into the HAS option and update this thread if it works.

Thank you for the suggestions.