Table of Contents
27.5.2 Class RpcClient
You can create an object of the class RpcClient (gb.xml.rpc) in this way:
Dim hRpcClient As RpcClient hRpcClient = New RpcClient(remoteFunction As RpcFunction) As "EVENT-NAME"
Note that you must have defined all the properties of a (new) RPC function before you can create a new RPC client object.
27.5.2.1 Properties
The class RpcClient has three properties:
| Property | Data type | Description |
|---|---|---|
| Mode | Integer | Specifies or sets the mode for the internally used HTTP server. These three constants can be used as values for the Mode property: Const offLine As Integer = 0, Const httpSync As Integer = 1 and Const httpAsync As Integer = 2. |
| RpcMethod | RpcFunction | This property can only be read and returns an Rpc function. |
| URL | String | The URL consists of the server's locator with the subsequent port number on which the XML RPC server listens. Example: localhost: 1088 |
Table 27.5.2.1.1: Properties of the RpcClient class
27.5.2.2 Methods
The class RpcClient has only these two methods:
| Method | Return type | Description |
|---|---|---|
| Function Call (Data As Variant[]) | Variant | Returns the function value of the method call. Data is a variant array with the arguments passed to the server. |
| Function EvalReply (sCad As String) | Variant | Returns the data part of an XML-RPC response. This data can be of the following types: integer, float, string, boolean, array or structure. |
Table 27.5.2.2.1: Methods of the class RpcClient
27.5.2.3 Client Project 1
For the first project, an XML-RPC-Server is started as the server for the first project → chapter 27.5.1 RPC-Server, which offers its services on a PC locally on port 1088. Port 1088 was chosen because it is above the first standard ports (>1023) and because it is not officially used or reserved. The following four functions can be called by the client via the RPC interface:
- system. methodHelp - The method' system. methodHelp' returns the help text if a help text is defined for the special method with RpcServer. help. Otherwise it returns an empty string.
Figure 27.5.2.3.1: Documentation of the add2integer function
- system. methodSignature - The method' system. methodSignature' returns an array of known signatures (as an array of arrays) for the special method name. If no signatures are known, it returns an empty array.
Figure 27.5.2.3.2: List of the signature of the add2integer function
- system. listMethods - The system. listMethods method lists all methods as elements in an array that are implemented for the RPC interface on the XML RPC server. The call takes place without arguments - the array of arguments is empty.
Figure 27.5.2.3.3.3: List of implemented functions
- add2integer - This method returns as a function value the sum of two integer numbers passed as argument.
Figure 27.5.2.3.3.4: Call of the method add2integer
Pay attention: In both projects, the data type and integer area are not checked for the two summands.
The source code for the XML RPC client is specified in full:
' Gambas class file Private $sRPCURL As String Private hXMLRPCFunction As RpcFunction Private hXMLRPCClient As RpcClient Private $aArguments As Variant[] Private $sRPCFunctionName As String Public Sub Form_Open() FMain.Resizable = False FMain.Title = "HTTP-SERVICE * RPC-CLIENT" txbSumme.ReadOnly = True ' $sRPCURL = "0.0.0.0:1088" ' $sRPCURL = "192.168.2.101:1088" ' $sRPCURL = "127.0.0.1:1088" $sRPCURL = "localhost:1088" ' This Port officially not used or reserved $sRPCFunctionName = "add2integer" End Public Sub btnGetResult_Click() GetResult() End Public Sub btnGetInformation_Click() GetDoc() GetSignatures() GetMethods() End Public Sub txbSummand1_Change() txbSumme.Clear() End Public Sub txbSummand2_Change() txbSumme.Clear() End Private Sub GetResult() Dim iResult As Integer $aArguments = New Variant[] hXMLRPCFunction = New RpcFunction($sRPCFunctionName, [XmlRpc.xInteger, XmlRpc.xInteger], XmlRpc.xInteger) hXMLRPCClient = New RpcClient(hXMLRPCFunction) As "hXMLRPCClient" hXMLRPCClient.URL = "http://" & $sRPCURL $aArguments.Add(CInt(txbSummand1.Text)) $aArguments.Add(CInt(txbSummand2.Text)) Try iResult = hXMLRPCClient.Call($aArguments) If Not Error Then txbSumme.Text = Str(iResult) Else Message.Error(("Error-Text: ") & Error.Text & gb.NewLine & ("Error-Location: ") & Error.Where & gb.NewLine & ("URL: '") & $sRPCURL & " '") Endif End Private Sub GetDoc() Dim sResult As String $aArguments = New Variant[] hXMLRPCFunction = New RpcFunction("system.methodHelp", [XmlRpc.xString], XmlRpc.xString) hXMLRPCClient = New RpcClient(hXMLRPCFunction) As "hXMLRPCClient" hXMLRPCClient.URL = "http://" & $sRPCURL $aArguments.Add("add2integer") Try sResult = hXMLRPCClient.Call($aArguments) If Not Error Then Message.Title = ("Description of the function") Message.Info(("Function: ") & $sRPCFunctionName & "<hr>" & sResult) Else Message.Error(("Error-Text: ") & Error.Text) Endif End Private Sub GetSignatures() Dim aResult As New RpcArray Dim sMessage As String Dim iIndex As Integer $aArguments = New Variant[] hXMLRPCFunction = New RpcFunction("system.methodSignature", [XmlRpc.xString], XmlRpc.xArray) hXMLRPCClient = New RpcClient(hXMLRPCFunction) As "hXMLRPCClient" hXMLRPCClient.URL = "http://" & $sRPCURL $aArguments.Add("add2integer") Try aResult = hXMLRPCClient.Call($aArguments) If Not Error Then Message.Title = ("List of data types") sMessage = ("List of data types of the function") sMessage &= "<font color='red'>" & $sRPCFunctionName & "</font>" sMessage &= "<hr>" For iIndex = 1 To aResult.Count If iIndex = 1 Then sMessage &= ("Function value ") & " = " & aResult[iIndex - 1] & gb.NewLine Else If iIndex = aResult.Count Then sMessage &= "Argument " & Str(iIndex - 1) & " = " & aResult[iIndex - 1] Else sMessage &= "Argument " & Str(iIndex - 1) & " = " & aResult[iIndex - 1] & gb.NewLine Endif Endif Next Message.Info(sMessage) Else Message.Error(("Error-Text: ") & Error.Text) Endif End Private Sub GetMethods() Dim aResult As New RpcArray Dim sMessage As String Dim iIndex As Integer $aArguments = New Variant[] hXMLRPCFunction = New RpcFunction("system.listMethods", [], XmlRpc.xArray) hXMLRPCClient = New RpcClient(hXMLRPCFunction) As "hXMLRPCClient" hXMLRPCClient.URL = "http://" & $sRPCURL Try aResult = hXMLRPCClient.Call($aArguments) If Not Error Then Message.Title = ("List of funktions") sMessage = ("Functions on the RPC server") & "<hr>" For iIndex = 1 To aResult.Count sMessage &= aResult[iIndex - 1] & gb.NewLine Next Message.Info(sMessage) Else Message.Error(("Error-Text: ") & Error.Text) Endif End
27.5.2.4 Client Project 2
In contrast to the first project, an XML-RPC-Server is only started if the PHP file xmlrpc.server.php is called in the web folder ~/public_html → chapter 27.5.1 and 24.13. Therefore, the source code for Client2 differs from Client1 from Project 1 mainly in the different diction of the URL. As a function, add2integer is implemented as in the first project.
' Gambas class file Private $sRPCURL As String Public Sub Form_Open() FMain.Resizable = False FMain.Title = "WEBSERVICE * RPC-CLIENT" txbSumme.ReadOnly = True $sRPCURL = "localhost/~" & System.User.Name &/ "xmlrpc.server.php" End Public Sub btnGetResult_Click() GetResult() End Public Sub txbSummand1_Change() txbSumme.Clear() End Public Sub txbSummand2_Change() txbSumme.Clear() End Private Sub GetResult() Dim hXMLRPCClient As RpcClient Dim hXMLRPCFunction As RpcFunction Dim aArguments As New Variant[] Dim iResult As Integer hXMLRPCFunction = New RpcFunction("add2integer", [XmlRpc.xInteger, XmlRpc.xInteger], XmlRpc.xInteger) hXMLRPCClient = New RpcClient(hXMLRPCFunction) As "hXMLRPCClient" hXMLRPCClient.URL = "http://" & $sRPCURL aArguments.Add(CInt(txbSummand1.Text)) aArguments.Add(CInt(txbSummand2.Text)) Try iResult = hXMLRPCClient.Call(aArguments) If Not Error Then txbSumme.Text = Str(iResult) Else Message.Error("Error-Text: " & Error.Text & gb.NewLine & "Error-Location: " & Error.Where & gb.NewLine & "URL: '" & $sRPCURL & " '") Endif End
The result of the algebraic addition will probably not surprise you:
Figure 27.5.2.4.1: Calling the add2integer function implemented on an RPC server (PHP)