ReadFromWeb - method of the PmaData object
Description:
Reading data from Web server in the XML format into this object.
Syntax:
Boolean ReadFromWeb(String URL, [String sUser], [String sPassword])
Parameters:
| URL | (String) The URL address of the data Web server where the XML data are stored.
The PROMOTIC application as the Web server offers the data usually on the path (see the "PmaData > Web server" tab):
http://ComputerName:Port/ComponentId/data.xml?fmt=purevalue
Caution! Head of the address ("http:") must be entered! If you want to enter the address of the local computer, then it is possible to enter the localhost word as the ComputerName. The Port needn't be entered if the Web server is on the standard port 80.
The communication also works on secured Web server at address https://....
fmt - Named format of the sent XML data.
purevalue - Shortened text format containing only the values separated by semicolon. This format can be used for sending values of all variables.
xmlpurevq - A shortened text format containing the values and qualities separated by semicolon. This format is suitable for sending values and qualities of all variables.
full - Extended text XML format containing values and variable names. This format can be used for sending values of some variables. |
|---|
| sUser | [optional](String) User name for the authentication. See "WebRead" permission on the server. If not set and the site requires the authentication, then the onEndOfTransfer event is triggered with the pEvent.Error=62. |
|---|
| sPassword | [optional](String) Password of the user for the authentication. This parameter is ignored if the sUser parameter is missing. |
|---|
Return values:
true - The method successfully
queued the request for reading data from server. After data transfer
the onEndOfTransfer event is triggered.
false - The method
hasn't queued the request for reading data. Probably the previous request about sending/receiving of this object hasn't been finished yet. The
onEndOfTransfer event
is not triggered.
Note:
This method
is not functional for
PmFree.
By the fact that the
ReadFromWeb method is called over the object, this object is regarded as the
Web client that reads data from the component of the Web server, in this case from another but the same configured
PmaData object in another application on the same or another computer.
The method only activates the data transfer but there is no assurance that data are already transferred after ending this method. The data transfer termination is announced by the the
onEndOfTransfer event. During the data transfer (i.e. in the time after calling the
ReadFromWeb method and before the
onEndOfTransfer event is triggered) the
ReadFromWeb nor the
WriteToWeb method cannot be called over the object again - then the method returns the
false value. By means of the
WebClientIsReady property it can be found out if the object is ready for the next transfer.
Variables on the "
Data" tab of this object are filled up by the incoming data.
Example:
JavaScriptVBScriptSelect and copy to clipboard
var oData = pMe.Pm("Data/Param1");
if (oData.WebClientIsReady)
{
oData.ReadFromWeb("http://localhost/param/data.xml?fmt=purevalue", "Johny", "abcd");
}
else
{
Pm.Debug("Web client PARAM is not ready (is still active)");
}
Dim oData
Set oData = pMe.Pm("Data/Param1")
If oData.WebClientIsReady Then
oData.ReadFromWeb "http://localhost/param/data.xml?fmt=purevalue", "Johny", "abcd"
Else
Pm.Debug "Web client PARAM is not ready (is still active)"
End If
History:
Pm9.00.18: New format of xmlpurevq for sending values and qualities of variables
Pm8.00.11: If the application tried to read Web pages from itself (e.g. by the
PmaData.ReadFromWeb method, when the URL address is address of this application), then the data was read with an error.