I can generalize the technical use-cases you described into two categories: payload modification, and payload validation.
For #4, validating against an Enum, that sounds like a job for JSON Schema. You could do that with the OpenAPI Spec validator, or ... if you don't want the full validation of the request, and you want only the validation of the JSON payload itself, then you can use your own JSON Schema validator.
For #1, #2, and #3, these are all just different flavors of the general case of "modifying a payload within the proxy." And I agree with Christian, use a JavaScript callout. In all cases, you will: (a) parse the payload into a JSON object. (b) mdoify the object. (c) stringify the resulting JSON object
For #1, you want to replace a property name. Use something like this:
var c = JSON.parse(context.getVariable('request.content'));
c.xyz = c.abc;
delete c.abc;
context.setVariable('request.content', JSON.stringify(c));
For #2, you want to replace a complex object, and Wrap it into a list. You can do this with JavaScript that is not very different form the above:
var c = JSON.parse(context.getVariable('request.content'));
var loclist = [c.location];
delete c.location;
context.setVariable('request.content', JSON.stringify(c));
For #3, now you are talking about something a little more interesting. Of course the simple way to solve it is to just add the set of default fields, like this:
var c = JSON.parse(context.getVariable('request.content'));
c.addedField1 = VALUE1;
c.addedField2 = VALUE2;
context.setVariable('request.content', JSON.stringify(c));
But that's not a very nice, scalable solution. I assume the set of defaults will
- be spread across the entire JSON payload
- vary according to the app, the client, the user, etc.
For those reasons the simple JS shown above won't satisfy to set defaults.
Instead what you need is
- a way to walk through the JSON graph to set defaults at whatever level
- a way to retrieve the defaults to use for each app, client, user, or etc.
To solve the first challenge you can use a recursive function. It might look like this:
function isObject(item) {
return (item && typeof item === 'object' && !Array.isArray(item));
}
function deepMerge(orig, defaults) {
var output = {};
if (isObject(orig) && isObject(defaults)) {
Object.keys(orig).forEach(function(key) {
output[key] = orig[key];
});
Object.keys(defaults).forEach(function(key) {
if (key in output) {
if (isObject(defaults[key])) {
output[key] = deepMerge(output[key], defaults[key]);
}
}
else {
output[key] = defaults[key];
}
});
}
return output;
}
To solve the second challenge, just use a custom attribute on the API Product, or client or app or token.
Please find attached a working example. Using defaults of
{
"field1" : 24,
"phn" : {
"type" : "mobile"
}
}
if I pass in
{
"name" : "Chris",
"phn" : {
"num" : "201-555-1212"
}
}
...then the output is:
{
"name": "Chris",
"phn": {
"num": "201-555-1212",
"type": "mobile"
},
"field1": 24
}
Whereas if I provide input of:
{
"name" : "Chris",
"phn" : {
"num" : "201-555-1212",
"type" : "work"
}
}
...then I get this output:
{
"name": "Chris",
"phn": {
"num": "201-555-1212",
"type": "work"
},
"field1": 24
}
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