HTTP Request

HTTP Request (PRIM_WEB.HttpRequest)

HTTP request to an external web resource

Details

An HTTPRequest allows access to 3rd party HTTP services, allowing LANSA to integrate with other web services.
 
An HTTPRequest is effectively a standard XMLHttpRequest in JavaScript.
 
HTTPRequests should be defined within the routine in which they are going to execute. This will create a new instance every time one is executed. The corresponding event routines for the Completed and Failed events are coded in the same routine.
 
The LANSA runtime maintains the instances until they have finished. This allows the same routine to be execute many times and many requests to execute, each one independently producing results.
 
If the HTTPRequest exists as a global scope, there will only ever be one instance.
 
HTTPRequest instances can't be defined with an EVTROUTINE as events cannot have other child events routines.

Example

In this example, a weather API is executed asynchronously, returning the data as a JSON object.
 
When the completed event fires, the result is processed.

Mthroutine Name(GetWeather) Access(*Private)
   Define_Map For(*Input) Class(#prim_alph) Name(#Resource)
 
   Define_Com Class(#PRIM_WEB.HttpRequest) Name(#Request)
 
   #Request.URL := "http://api.openweathermap.org" + #Resource
 
   #Request.ExecuteAsync
 
   Evtroutine Handling(#Request.Completed)
 
      If (#Request.Response *IsNot *null)
 
      Case (#Request.Response.Status)
      When (= 200)
 
         #Com_owner.Update( #Request.Response.JSON.RootItem )
 
      Otherwise
 
         #Com_owner.UpdateForFailure( #Request )
 
      Endcase
 
      Endif
 
   Endroutine
 
Endroutine

Properties

Name	Description
ComponentClassName	ComponentClassName is the name of the component's class. Inherited from Object (PRIM_OBJT)
ComponentMembers	ComponentMembers provides access to all the member components of this component Inherited from Object (PRIM_OBJT)
ComponentPatternName	ComponentPatternName is used to qualify the class of the component. Inherited from Object (PRIM_OBJT)
ComponentTag	Generic space allowing a value to be stored for the instance Inherited from Object (PRIM_OBJT)
ComponentType	ComponentType gives you access to the type information about the component Inherited from Object (PRIM_OBJT)
ComponentTypeName	ComponentTypeName is the fully qualified name of the component's class. Inherited from Object (PRIM_OBJT)
Content	The content of an HTTP request
Headers	HTTP Headers
Method	Standard HTTP request methods such as GET, POST etc.
Name	Name identifies the component Inherited from Object (PRIM_OBJT)
Owner	Owner owns this component Inherited from Object (PRIM_OBJT)
Parent	The component instance to which this instance is attached. The visual container for a control or the collector of a set of child instances Inherited from Object (PRIM_OBJT)
Response	Reference to an HTTP Response object returned by the request
Status	Standard HTTP request status code
Timeout	Standard HTTP request timeout
Url	URL of the request

Events

Name	Description
Completed	Fired when the HTTP request returns after processing successfully
CreateInstance	CreateInstance is signalled when an instance of a component is created Inherited from HTTP Request (PRIM_WEB.HttpRequest)
DestroyInstance	DestroyInstance is signalled when an instance of a component is about to be destroyed Inherited from HTTP Request (PRIM_WEB.HttpRequest)
Failed	Fired when the HTTP request returns after processing unsuccessfully

Methods

Name	Description
Cancel	Cancel the HTTP request
Execute	Execute the Request synchronously
ExecuteAsync	Execute the request asynchronously

Details

Example

Properties

Events

Methods

See also