OutgoingMessage

The 4D.OutgoingMessage class allows you to build messages to be returned by your application functions in response to REST requests. If the response is of type 4D.OutgoingMessage, the REST server does not return an object but the object instance of the OutgoingMessage class.

Typically, this class can be used in functions declared with the onHttpGet keyword and designed to handle HTTP GET requests. Such requests are used, for example, to implement features such as download file, generate and download picture as well as receiving any content-type via a browser.

An instance of this class is built on the Qodly server and can be sent to the browser by the REST Server only. This class allows to use other technologies than HTTP (e.g. mobile).

Example

In this example, a getFile() function is implemented in the Datastore class and can be called by a REST request. The purpose is to return a testFile.pdf file as a response to the request:

extends DataStoreImplementation

exposed onHTTPGet function getFile() : 4D.OutgoingMessage
	
	var result = 4D.OutgoingMessage.new()
	var vfile = file("/SOURCES/Shared/testFile.pdf")
	
	result.setBody(vfile.getContent())  
	result.setHeader("Content-Type", "application/pdf")
	return result

OutgoingMessage Object

4D.OutgoingMessage objects provide the following properties and functions:

note

A 4D.OutgoingMessage object is a non-sharable object.

.body

body* : any

Description

The .body property contains the outgoing message body. The following data types are supported in the .body property:

• text
• blob
• object
• image

The .body property is read-write.

You can also set the .body property using the setBody() function, in which case the content-type header is automatically set.

.headers

headers* : object

Description

The .headers property contains the current headers of the outgoing message as key/value pairs.

The .headers property is read-only. To set a header, use the setHeader() function.

.setBody()

.setBody*( body : any )

Parameter	Type		Description
body	any	→	Body of the outgoing message

Description

The .setBody() function sets the outgoing message body.

The following data types are supported in the body:

• text
• blob
• object
• image

When this function is used, the content-type header is automatically set depending on the body type:

• Content-Type:text/plain if the body is a text
• Content-Type:application/octet-stream if body is a blob
• Content-Type:application/json if body is an object
• Content-Type:image/jpeg, image/gif... if body is an image

If body is not of a supported value type, an error is returned.

.setHeader()

.setHeader*( key : string , value : string )

Parameter	Type		Description
key	string	→	Header property to set
value	string	→	Value of the header property

Description

The .setHeader() function sets the outgoing message header key with the provided value. If both parameters are not Text values, an error is raised.

When returning a 4D.OutgoingMessage object instance, 4D automatically sets some headers (e.g. Set-Cookie with WASID4D=... and 4DSID__ProjectName_=....).

note

If you set a value for the "Content-Type" header key, make sure you call this function after the call to setBody(), because setBody() automatically fills this header.

.setStatus()

.setStatus*( status : integer )

Parameter	Type		Description
status	integer	→	Status to set

Description

The .setStatus() function sets the status property with the given status.

If status is not an integer value, an error is raised.

For a list of HTTP status codes, please refer the HTTP status code list on Wikipedia.

.status

status* : integer

Description

The .status property contains the current status of the outgoing message. This property can be set using the setStatus() function.