Version: 20 R7 BETA

Calling class functions

You can call data model class functions defined for the ORDA Data Model and singleton class functions through REST requests, so that you can benefit from the exposed API of the targeted 4D application.

Functions can be called in two ways:

using POST requests, with data parameters passed in the body of the request.
using GET requests, with parameters directly passed in the URL.

POST requests provide a better security level because they avoid running sensitive code through an action as simple as clicking on a link. However, GET requests can be more compliant with user experience, allowing to call functions by entering an URL in a browser (note: the developer must ensure no sensitive action is done in such functions).

Function calls

The following ORDA and singleton functions can be called in REST:

Class function	Syntax
datastore class	`/rest/$catalog/DataStoreClassFunction`
dataclass class	`/rest/\{dataClass\}/DataClassClassFunction`
entitySelection class	`/rest/\{dataClass\}/EntitySelectionClassFunction`
	`/rest/{dataClass}/EntitySelectionClassFunction/$entityset/entitySetNumber`
	`/rest/{dataClass}/EntitySelectionClassFunction/$filter`
	`/rest/{dataClass}/EntitySelectionClassFunction/$orderby`
entity class	`/rest/{dataClass}(key)/EntityClassFunction/`
Singleton class	`/rest/$singleton/SingletonClass/SingletonClassFunction` (see $singleton page)

note

/rest/{dataClass}/Function can be used to call either a dataclass or an entity selection function (/rest/{dataClass} returns all entities of the DataClass as an entity selection). The function is searched in the entity selection class first. If not found, it is searched in the dataclass. In other words, if a function with the same name is defined in both the DataClass class and the EntitySelection class, the dataclass class function will never be executed.

Functions are simply called on the appropriate ORDA interface or singleton class, without (). Parameters are passed either in the body of the POST request (POST calls) or in the params collection in the URL (GET calls).

For example, if you have defined a getCity() function in the City dataclass class, you could call it using the following request:

POST request

/rest/City/getCity

with data in the body of the POST request: ["Aguada"]

GET request

/rest/City/getCity?$params='["Aguada"]'

note

The getCity() function must have been declared with the onHttpGet keyword (see Function configuration below).

In 4D language, this call is equivalent to:

$city:=ds.City.getCity("Aguada")

Function configuration

`exposed`

All functions allowed to be called directly from HTTP REST requests (POST or GET) must be declared with the exposed keyword. For example:

exposed Function getSomeInfo() : 4D.OutgoingMessage

See Exposed vs non-exposed functions section.

`onHttpGet`

Functions allowed to be called from HTTP GET requests must also be specifically declared with the onHttpGet keyword. For example:

//allowing GET requests
exposed onHttpGet Function getSomeInfo() : 4D.OutgoingMessage

Thread-safe

All 4D code called from REST requests must be thread-safe if the project runs in compiled mode, because the REST Server always uses preemptive processes in this case (the Use preemptive process setting value is ignored by the REST Server).

info

You can restrict calls to specific ORDA functions by configuring appropriate privileges in the roles.json file.

Parameters

You can send parameters to functions defined in ORDA user classes or singletons. On the server side, they will be received in the declared parameters of the class functions.

The following rules apply:

In functions called through POST requests, parameters must be passed in the body of the POST request.
In functions called through GET requests, parameters must be passed in the URL with "?$params=" syntax.
Parameters must be enclosed within a collection (JSON format).
All scalar data types supported in JSON collections can be passed as parameters.
Entity and entity selection can be passed as parameters. The parameter list must contain specific attributes used by the REST server to assign data to the corresponding ORDA objects: __DATACLASS, __ENTITY, __ENTITIES, __DATASET.

See this example and this example.

Scalar value parameter

Scalar value parameter(s) must simply be enclosed in a collection. All JSON data types are supported in parameters, including JSON pointers. Dates can be passed as strings in ISO 8601 date format (e.g. "2020-08-22T22:00:000Z").

For example, with a dataclass function getCities() receiving text parameters:

POST request

/rest/City/getCities

Parameters in body: ["Aguada","Paris"]

GET request

/rest/City/getCities?$params='["Aguada","Paris"]'

Entity parameter

Entities passed in parameters are referenced on the server through their key (i.e. __KEY property). If the key parameter is omitted in a request, a new entity is loaded in memory on the server. You can also pass values for any attributes of the entity. These values will automatically be used for the entity handled on the server.

If the request sends modified attribute values for an existing entity on the server, the called ORDA data model function will be automatically executed on the server with modified values. This feature allows you, for example, to check the result of an operation on an entity, after applying all business rules, from the client application. You can then decide to save or not the entity on the server.

Properties	Type	Description
Attributes of the entity	mixed	Optional - Values to modify
__DATACLASS	Text	Mandatory - Indicates the Dataclass of the entity
__ENTITY	Boolean	Mandatory - True to indicate to the server that the parameter is an entity
__KEY	mixed (same type as the primary key)	Optional - Primary key of the entity

If __KEY is not provided, a new entity is created on the server with the given attributes.
If __KEY is provided, the entity corresponding to __KEY is loaded on the server with the given attributes

See examples for creating or updating entities with POST requests. See an example of contents downloading using an entity with a GET request.

Same properties as for an entity parameter. In addition, the related entity must exist and is referenced by __KEY containing its primary key.

See examples for creating or updating entities with related entities.

Entity selection parameter

The entity selection must have been defined beforehand using $method=entityset.

If the request sends a modified entity selection to the server, the called ORDA data model function will be automatically executed on the server with the modified entity selection.

Properties	Type	Description
Attributes of the entity	mixed	Optional - Values to modify
__DATASET	Text	Mandatory - entitySetID (UUID) of the entity selection
__ENTITIES	Boolean	Mandatory - True to indicate to the server that the parameter is an entity selection

See example for receiving an entity selection with a POST request. See example for getting a list built upon an entity selection with a GET request.

POST request examples

This database is exposed as a remote datastore on localhost (port 8111):

alt-text

Using a datastore class function

The US_Cities DataStore class provides an API:

// DataStore class

Class extends DataStoreImplementation

exposed Function getName() : Text
    return "US cities and zip codes manager"

You can then run this request:

POST 127.0.0.1:8111/rest/$catalog/getName

Result

{
"result": "US cities and zip codes manager"
}

Using a dataclass class function

The Dataclass class City provides an API that returns a city entity from a name passed in parameter:

// City class

Class extends DataClass

exposed Function getCity($city : Text ) : cs.CityEntity
	return This.query("name = :1";$city).first()

You can then run this request:

POST 127.0.0.1:8111/rest/City/getCity

Body of the request: ["Aguada"]

Result

The result is an entity:

{
    "__entityModel": "City",
    "__DATACLASS": "City",
    "__KEY": "1",
    "__TIMESTAMP": "2020-03-09T08:03:19.923Z",
    "__STAMP": 1,
    "ID": 1,
    "name": "Aguada",
    "countyFIPS": 72003,
    "county": {
        "__deferred": {
            "uri": "/rest/County(72003)",
            "__KEY": "72003"
        }
    },
    "zips": {
        "__deferred": {
            "uri": "/rest/City(1)/zips?$expand=zips"
        }
    }
}

Using an entity class function

The Entity class CityEntity provides an API:

// CityEntity class

Class extends Entity

exposed Function getPopulation()
    return This.zips.sum("population")

You can then run this request:

POST 127.0.0.1:8111/rest/City(2)/getPopulation

Result

{
    "result": 48814
}

Using an entitySelection class function

The EntitySelection class CitySelection provides an API:

// CitySelection class

Class extends EntitySelection

exposed Function getPopulation()
    return This.zips.sum("population")

You can then run this request:

POST 127.0.0.1:8111/rest/City/getPopulation/?$filter="ID<3"

Result

{
    "result": 87256
}

Using an entitySelection class function and an entitySet

The StudentsSelection class has a getAgeAverage function:

// StudentsSelection Class

Class extends EntitySelection

exposed Function getAgeAverage : Integer
	var $sum : Integer
	var $s : Object

	$sum:=0
	For each ($s;This)
	    $sum:=$sum+$s.age()
	End for each
	return $sum/This.length

Once you have created an entityset, you can run this request:

POST 127.0.0.1:8044/rest/Students/getAgeAverage/$entityset/17E83633FFB54ECDBF947E5C620BB532

Result

{
    "result": 34
}

Using an entitySelection class function and an orderBy

The StudentsSelection class has a getLastSummary function:

// StudentsSelection Class


Class extends EntitySelection

exposed Function getLastSummary : Text
	var $last : Object

	$last:=This.last()
	return =$last.firstname+" - "+$last.lastname+" is ... "+String($last.age())

You can then run this request:

POST 127.0.0.1:8044/rest/Students/getLastSummary/$entityset/?$filter="lastname=b@"&$orderby="lastname"

Result

{
    "result": "Wilbert - Bull is ... 21"
}

Using an entity to be created on the server

The Dataclass class Students has the function pushData() receiving an entity containing data from the client. The checkData() method runs some controls. If they are OK, the entity is saved and returned.

// Students Class

Class extends DataClass

exposed Function pushData($entity : Object) : Object
	var $status : Object

	$status:=checkData($entity) // $status is an object with a success boolean property

	If ($status.success)
	    $status:=$entity.save()
 	   If ($status.success)
 	       return $entity
  	  End if
	End if

	return $status

You run this request:

POST http://127.0.0.1:8044/rest/Students/pushData

Body of the request:

[{
"__DATACLASS":"Students",
"__ENTITY":true,
"firstname":"Ann",
"lastname":"Brown"
}]

Since no __KEY is given, a new Students entity is loaded on the server with the attributes received from the client. Because the pushData() function runs a save() action, the new entity is created.

Result

{
    "__entityModel": "Students",
    "__DATACLASS": "Students",
    "__KEY": "55",
    "__TIMESTAMP": "2020-06-16T10:54:41.805Z",
    "__STAMP": 1,
    "ID": 55,
    "firstname": "Ann",
    "lastname": "BROWN",
    "schoolID": null,
    "school": null
}

Using an entity to be updated on the server

Same as above but with a __KEY attribute

You run this request:

POST:http://127.0.0.1:8044/rest/Students/pushData

Body of the request:

[{
"__DATACLASS":"Students",
"__ENTITY":true,
"lastname":"Brownie",
"__KEY":55
}]

Since __KEY is given, the Students entity with primary key 55 is loaded with the lastname value received from the client. Because the function runs a save() action, the entity is updated.

Result

{
    "__entityModel": "Students",
    "__DATACLASS": "Students",
    "__KEY": "55",
    "__TIMESTAMP": "2020-06-16T11:10:21.679Z",
    "__STAMP": 3,
    "ID": 55,
    "firstname": "Ann",
    "lastname": "BROWNIE",
    "schoolID": null,
    "school": null
}

In this example, we create a new Students entity with the Schools entity having primary key 2.

You run this request:

POST:http://127.0.0.1:8044/rest/Students/pushData

Body of the request:

[{
"__DATACLASS":"Students",
"__ENTITY":true,
"firstname":"John",
"lastname":"Smith",
"school":{"__KEY":2}
}]

Result

{
    "__entityModel": "Students",
    "__DATACLASS": "Students",
    "__KEY": "56",
    "__TIMESTAMP": "2020-06-16T11:16:47.601Z",
    "__STAMP": 1,
    "ID": 56,
    "firstname": "John",
    "lastname": "SMITH",
    "schoolID": 2,
       "school": {
        "__deferred": {
            "uri": "/rest/Schools(2)",
            "__KEY": "2"
        }
    }
}

In this example, we associate an existing school to a Students entity. The StudentsEntity class has an API:

// StudentsEntity class

Class extends Entity

exposed Function putToSchool()
	var $1, $school , $0, $status : Object

		//$1 is a Schools entity
	$school:=$1
		//Associate the related entity school to the current Students entity
	This.school:=$school

	$status:=This.save()

	$0:=$status

You run this request, called on a Students entity : POST http://127.0.0.1:8044/rest/Students(1)/putToSchool Body of the request:

[{
"__DATACLASS":"Schools",
"__ENTITY":true,
"__KEY":2
}]

Result

{
    "result": {
        "success": true
    }
}

Receiving an entity selection as parameter

In the Students Dataclass class, the setFinalExam() function updates a received entity selection ($1). It actually updates the finalExam attribute with the received value ($2). It returns the primary keys of the updated entities.

// Students class

Class extends DataClass

exposed Function setFinalExam()


    var $1, $es, $student, $status : Object
    var $2, $examResult : Text

    var $keys, $0 : Collection

      //Entity selection
    $es:=$1

    $examResult:=$2

    $keys:=New collection()

      //Loop on the entity selection
    For each ($student;$es)
        $student.finalExam:=$examResult
        $status:=$student.save()
        If ($status.success)
            $keys.push($student.ID)
        End if
    End for each

    $0:=$keys

An entity set is first created with this request:

http://127.0.0.1:8044/rest/Students/?$filter="ID<3"&$method=entityset

Then you can run this request:

POST http://127.0.0.1:8044/rest/Students/setFinalExam

Body of the request:

[
{
"__ENTITIES":true,
"__DATASET":"9B9C053A111E4A288E9C1E48965FE671"
},
"Passed"
]

Result

The entities with primary keys 1 and 2 have been updated.

{
    "result": [
        1,
        2
    ]
}

Using an entity selection updated on the client

Using the getAgeAverage() function defined above.

var $remoteDS, $newStudent, $students : Object
var $ageAverage : Integer

$remoteDS:=Open datastore(New object("hostname";"127.0.0.1:8044");"students")

// $newStudent is a student entity to procees
$newStudent:=...
$students:=$remoteDS.Students.query("school.name = :1";"Math school")
// We add an entity to the $students entity selection on the client
$students.add($newStudent)

// We call a function on the StudentsSelection class returning the age average of the students in the entity selection
// The function is executed on the server on the updated $students entity selection which included the student added from the client
$ageAverage:=$students.getAgeAverage()

GET request examples

Returning a document

You want to propose a link to download the user manual for a selected product with several formats available. You write a getUserManual() function of the Products dataclass. You return an object of the OutgoingMessage class.

// Product dataclass
exposed onHTTPGet Function getUserManual($productId : Integer; $type : Text) : 4D.OutgoingMessage
	
var $file : 4D.File
var $response:=4D.OutgoingMessage.new()
var $doc:="/RESOURCES/User manuals/product_"+String($productId)

Case of 
	: ($type="pdf")
		$file:=File($doc+".pdf")
                $response.setBody($file.getContent()) // This is binary content 
		$response.setHeader("Content-Type"; "application/pdf")
			
	: ($type="jpeg")
		$file:=File($doc+".jpeg")
                $response.setBody($file.getContent()) // This is binary content 
		$response.setHeader("Content-Type"; "image/jpeg")
End case 
	
return $response

You can call the function using a request like:

GET http://127.0.0.1:8044/rest/Products/getUserManual?$params='[1,"pdf"]'

Using an entity to download a PDF document

Same example as above but you want to pass an entity as parameter to the datastore function.

// Product dataclass
exposed onHTTPGet Function getUserManual($product : cs.ProductEntity) : 4D.OutgoingMessage
	
	var $file : 4D.File
	var $response := 4D.OutgoingMessage.new()
	
	$file:=File("/RESOURCES/User manuals/"+$product.name+".pdf")
	$response.setBody($file.getContent())
	$response.setHeader("Content-Type"; "application/pdf")
	
	return $response

You can call the function using this request:

GET http://127.0.0.1:8044/rest/Product/getUserManual?$params='[{"__DATACLASS":"Product","__ENTITY":true,"__KEY":41}]'

Using an entity selection to get a list

You want to send an entity selection as parameter to a singleton function using a REST GET request and return a list using an object of the OutgoingMessage class.

shared singleton Class constructor()
	
exposed onHTTPGet Function buildShoppingList($products : cs.ProductSelection) : 4D.OutgoingMessage
	
	var $p : cs.ProductsEntity
	var $content : Text
	var $response := 4D.OutgoingMessage.new()
	
	$content:=""
	
	For each ($p; $products)
		$content:=$content+" "+$p.manufacturer+" - "+$p.name
		$content:=$content+Char(Carriage return)
	End for each 
	
	$response.setBody($content)
	$response.setHeader("Content-Type"; "text/plain")
	
	return $response

You can call the function using this request:

GET http://127.0.0.1:8044/rest/$singleton/Shopping/buildShoppingList?$params='[{"__DATASET":"8DB0556854HDK52FR5974F","__ENTITIES":true}]'

Function calls​

POST request​

GET request​

Function configuration​

exposed​

onHttpGet​

Thread-safe​

Parameters​

Scalar value parameter​

POST request​

GET request​

Entity parameter​

Related entity parameter​

Entity selection parameter​

POST request examples​

Using a datastore class function​

Result​

Using a dataclass class function​

Result​

Using an entity class function​

Result​

Using an entitySelection class function​

Result​

Using an entitySelection class function and an entitySet​

Result​

Using an entitySelection class function and an orderBy​

Result​

Using an entity to be created on the server​

Result​

Using an entity to be updated on the server​

Result​

Creating an entity with a related entity​

Result​

Updating an entity with a related entity​

Result​

Receiving an entity selection as parameter​

Result​

Using an entity selection updated on the client​

GET request examples​

Returning a document​

Using an entity to download a PDF document​

Using an entity selection to get a list​

Function calls

POST request

GET request

Function configuration

`exposed`

`onHttpGet`

Thread-safe

Parameters

Scalar value parameter

POST request

GET request

Entity parameter

Related entity parameter

Entity selection parameter

POST request examples

Using a datastore class function

Result

Using a dataclass class function

Result

Using an entity class function

Result

Using an entitySelection class function

Result

Using an entitySelection class function and an entitySet

Result

Using an entitySelection class function and an orderBy

Result

Using an entity to be created on the server

Result

Using an entity to be updated on the server

Result

Creating an entity with a related entity

Result

Updating an entity with a related entity

Result

Receiving an entity selection as parameter

Result

Using an entity selection updated on the client

GET request examples

Returning a document

Using an entity to download a PDF document

Using an entity selection to get a list