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In our How do I create a resource? article we introduced the GetObject service as a primary method for creating resource objects. To keep our documentation focused on creating a resource objects, we did not introduce hypermedia. Now we will use the same code sample and introduce a new service: AddLinkRelationship. The AddLinkRelationship service creates the HAL _links reserved property:
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|---|---|---|
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API contacts.ID.GET
KeyID = EndpointSegment
ColumnNames = 'FIRST_NAME' : @FM : 'LAST_NAME' : @FM : 'ADDRESS' : @FM : 'CITY' : @FM : 'STATE' : @FM : 'ZIP'
PropertyNames = 'firstName' : @FM : 'lastName' : @FM : 'address' : @FM : 'city' : @FM : 'state' : @FM : 'zipCode'
// Create a JSON object in memory.
objResource = HTTP_Resource_Services('GetObject', 'CONTACTS', KeyID, ColumnNames, PropertyNames)
If Error_Services('NoError') then
// Add _links sub-properties for HAL implementation.
HTTP_Resource_Services('AddLinkRelation', objResource, 'self', FullEndpointURL)
HTTP_Resource_Services('AddLinkRelation', objResource, 'collection', ParentURL)
end
If Error_Services('NoError') then
// Serialize the JSON object.
jsonResource = HTTP_Resource_Services('GetSerializedResource', objResource)
// Set the response body with the serialized JSON object and set the Content-Type response header.
HTTP_Services('SetResponseBody', jsonResource, False$, 'application/hal+json')
end else
// There is an error condition so call the SetResponseError service.
HTTP_Services('SetResponseError', '', '', 500, Error_Services('GetMessage'), FullEndpointURL)
end
end api |
By using the FullEndpointURL and the ParentURL prepopulated variables, we automatically have the self and collection hypermedia relations ready to add to the reserved _links property:
| Code Block | ||
|---|---|---|
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{
"address":"6649 N Blue Gum St",
"city":"New Orleans",
"firstName":"James",
"lastName":"Butt",
"state":"LA",
"zipCode":"70116",
"_links":{
"self":{
"href":"https://www.examples.org/customers/1"
},
"collection":{
"href":"https://www.examples.org/customers"
}
}
} |
There is also a AddLinkRelations service. It's a wrapper around the AddLinkRelation service that allows the developer to pass in an @FM delimited list of relations and URLs into a single call. Developers will need to decide if the AddLinkRelations service provides enough convenience in lieu of multiple AddLinkRelation calls.
