IncomingMessage

The 4D.IncomingMessage class allows you to handle the object received by a custom HTTP request handler. HTTP requests and their properties are automatically received as an instance of the 4D.IncomingMessage class. Parameters given directly in the request with GET verb are handled by the .urlQuery property, while parameters passed in the body of the request are available through functions such as .getBlob() or getText().

The HTTP request handler can return any value (or nothing). It usually returns an instance of the 4D.OutgoingMessage class.

All properties of this class are read-only. They are automatically filled by the request handler.

History

Release	Changes
20 R8	Class added

Example

The following HTTPHandlers.json file has been defined:

[
    {
        "class": "GeneralHandling",
        "method": "gettingStarted",
        "pattern": "start",
        "verbs": "get, post"
    }
]

The http://127.0.0.1/start/example?param=demo&name=4D request is run with a GET verb in a browser. It is handled by the gettingStarted function of the following GeneralHandling singleton class:

shared singleton Class constructor()
        
Function gettingStarted($request : 4D.IncomingMessage) : 4D.OutgoingMessage
    
    var $result:=4D.OutgoingMessage.new()
    var $body : Text
    
    $body:="Called URL: "+$request.url+"\n"
    
    $body+="The parameters are received as an object: \n"+JSON Stringify($request.urlQuery; *)+"\n"
    
    $body+="The verb is: "+$request.verb+"\n"
    
    $body+="There are "+String($request.urlPath.length)+" url parts - Url parts are: "\
    +$request.urlPath.join(" - ")+"\n\n"
    
    
    $result.setBody($body)
    $result.setHeader("Content-Type"; "text/plain")
    
    return $result

The request is received on the server as $request, an object instance of the 4D.IncomingMessage class.

Here is the response:

Called URL: /start/example? param=demo&name=4D 
The parameters are received as an object:
{
  "param": "demo",
  "name": "4D"
}
The verb is: GET
There are 2 url parts - Url parts are: start - example

IncomingMessage Object

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

.getBlob() : Blob returns the body of the request as a Blob
.getHeader( key : Text ) : Text returns the value of the key header
.getJSON() : Variant returns the body of the request as a JSON resolution
.getPicture() : Picture returns the body of the request as a picture (in case of a body sent as a picture)
.getText() : Text returns the body of the request as a text value
headers : Object the current headers of the incoming message as key/value pairs (strings)
url : Text the URL of the request without the IP:port part and as a string
urlPath : Collection the URL of the request without the IP:port part and as a collection of strings
urlQuery : Object the parameters of the request when they have been given in the URL as key/value pairs
verb : Text the verb used by the request

note

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

.getBlob()

.getBlob() : Blob

Parameter	Type		Description
Result	Blob	<-	Body of the request as a Blob

Description

The .getBlob() function returns the body of the request as a Blob.

If the body has not been given as a binary content, the function tries to convert the value but it can give unexpected results.

.getHeader()

.getHeader( key : Text ) : Text

Parameter	Type		Description
key	Text	->	Header property to get
Result	Text	<-	Value of the header property

Description

The .getHeader() function returns the value of the key header.

note

The key parameter is not case sensitive.

Example

var $value : Text
var $request : 4D.IncomingMessage
$value := $request.getHeader("content-type")

.getJSON()

.getJSON() : Variant

Parameter	Type		Description
Result	Variant	<-	JSON resolution of the body of the request

Description

The .getJSON() function returns the body of the request as a JSON resolution.

If the body has not been given as JSON valid content, an error is raised.

.getPicture()

.getPicture() : Picture

Parameter	Type		Description
Result	Picture	<-	Body of the request as picture

Description

The .getPicture() function returns the body of the request as a picture (in case of a body sent as a picture).

The content-type must be given in the headers to indicate that the body is a picture.

note

If the request is built using the HTTPRequest class, the picture must be sent in the body as a Blob with the appropriate content-type.

If the body is not received as a valid picture, the function returns null.

.getText()

.getText() : Text

Parameter	Type		Description
Result	Text	<-	Body of the request as text

Description

The .getText() function returns the body of the request as a text value.

If the body has not been given as a string value, the function tries to convert the value but it can give unexpected results.

.headers

headers : Object

Description

The .headers property contains the current headers of the incoming message as key/value pairs (strings).

The .headers property is read-only.

Header names (keys) are lowercased. Note header names are case sensitive.

.url

url : Text

Description

The .url property contains the URL of the request without the IP:port part and as a string.

For example, if the request is addressed to: "http://127.0.0.1:80/docs/invoices/today", the .url property is "/docs/invoices/today".

The .url property is read-only.

note

The "host" part of the request (IP:port) is provided by the host header.

.urlPath

urlPath : Collection

Description

The .urlPath property contains the URL of the request without the IP:port part and as a collection of strings.

For example, if the request is addressed to: "http://127.0.0.1:80/docs/invoices/today", the .urlPath property is ["docs", "invoices" ,"today"].

The .urlPath property is read-only.

.urlQuery

urlQuery : Object

Description

The .urlQuery property contains the parameters of the request when they have been given in the URL as key/value pairs.

The .urlQuery property is read-only.

Parameters can be passed in the URL of requests directly or as JSON contents.

Direct parameters

Example: http://127.0.0.1:8044/myCall?firstname=Marie&id=2&isWoman=true

In this case, parameters are received as stringified values in the urlQuery property: urlQuery = {"firstname":"Marie" ,"id":"2" ,"isWoman":"true"}

JSON contents parameters

Example: http://127.0.0.1:8044/myCall/?myparams='[{"firstname": "Marie","isWoman": true,"id": 3}]'.

Parameters are passed in JSON format and enclosed within a collection.

In this case, parameters are received as JSON text in the urlQuery property and can be parsed using JSON Parse.

//urlQuery.myparams: "[{"firstname": "Marie","isWoman": true,"id": 3}]"
$test:=Value type(JSON Parse($r.urlQuery.myparams))=Is collection) //true

Special characters such as simple quotes or carriage returns must be escaped.

Example: http://127.0.0.1:8044/syntax/?mdcode=%60%60%604d

//urlQuery.mdcode = ```4d
$test:=Length($r.urlQuery.mdcode) //5

note

Parameters given in the body of the request using POST or PUT verbs are handled through dedicated functions: getText(), getPicture(), getBlob(), getJSON().

.verb

verb : Text

Description

The .verb property contains the verb used by the request.

HTTP and HTTPS request verbs include for example "get", "post", "put", etc.

The .verb property is read-only.