{ This is a sample IVR application written in Delphi.Net
All .Net IVR applications are implemented as classes derived by the base class NetClientcall
in the namespace IVRForBeginners. The class implements an application's voice user interface
in its Answer() method. This one speaks the current weather condition to a caller who has
identified the locality whose weather he wants by entering its ZIP code on his telephone's
keypad.
Please note that while the sample may not be considered short, that has to do with what the
sample does and not the form of its user interface. To put that another way, the entirety of
the voice user interface code is held in the short (3 dozen executable lines) subroutine
named Answer() which is below. }
unit DelphiNetWeatherDTMFApp;
interface
uses
{ from the Big House }
System.IO,
System.Net,
System.Web,
System.Xml,
System.Text,
System.Threading,
System.Reflection,
System.Collections,
{ from our house }
IVRForBeginners;
var
{ The data common to all instances of the application }
dirs : Hashtable;
states : Hashtable;
prompt : string;
welcome : string;
regrets : string;
patience : string;
baseQuery : string;
nameSpaceUri : string;
nameSpaceName : string;
type
TDelphiWeatherDTMF = class(IVRForBeginners.NetClientCall)
private
zip : array[0..5] of char;
iar : IAsyncResult;
req : WebRequest;
resp : HttpWebResponse;
weather : string;
class procedure BuildStatesTable();
procedure RequestWeather();
procedure CompleteRequest();
procedure CancelRequest();
function GetCity(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
function GetWind(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
function GetOutlook(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
function GetTemperature(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
function Direction(num : integer) : string;
public
procedure Answer();
class function Initialize() : System.Boolean; static;
end;
implementation
{ This function is called once when the application is loaded. It opens a
configuration file containing the user name and password for the web
service. It would be somewhat shorter if we wanted to hardcode the
credentials. It also builds a couple of hastables we use to translate
abbreviations to their pronounceable equivalents. }
class function TDelphiWeatherDTMF.Initialize() : System.Boolean;
begin;
prompt := 'Please enter a five digit ZIP code or press the pound key to quit.';
welcome := 'Welcome to the weather demonstration application.';
regrets := 'We are sorry but we had trouble determining the weather for that ZIP code. ' +
'If the ZIP code is valid you can try again later.';
patience := 'Please wait ...';
baseQuery := 'http://weather.yahooapis.com/forecastrss?p=';
nameSpaceUri := 'http://xml.weather.yahoo.com/ns/rss/1.0';
nameSpaceName := 'yweather';
BuildStatesTable();
result := true;
end;
{ The required Answer() method always comprises the entire Voice User
Interface for an IVR application. }
procedure TDelphiWeatherDTMF.Answer();
var
i : Integer;
c : char;
ok : Boolean;
syn : ISynthesizer;
done : Boolean;
millis : Integer;
begin
try
{ We want an exception if the user disconnects }
hangupThrows(true);
{ Get an instance of the synthesizer and greet the caller
We should check for a nil object which indicates failure }
syn := getSynthesizer();
syn.speak(welcome);
syn.wait();
done := false;
{ Keep going until the user gets bored }
while not isDisconnected() and not done do
begin
{ Ask the user for a ZIP code }
syn.speak(prompt);
syn.wait();
{ Wait for 5 strokes or a terminator but not more than 20 seconds }
ok := inputWait(5, '#', 20000);
{ If the time out elapses or the caller hangs up then we are done }
if not ok then
done := true;
{ We have no patience if we got fewer than 5 digits }
if inputAvailable() < 5 then
done := true;
{ Build a string from the key strokes
But if there is a '#' or '*' key in there we are done }
for i := 0 To 4 do
begin
c := getChar();
if (c <> '#') and (c <> '*') then
zip[i] := c
else
done := true
end;
zip[5] := #0;
{ We bail out if we don't have a complete ZIP code }
if not done then
begin
{ Tell the caller to be patient }
syn.speak(patience);
{ Initiate the request to the web service }
RequestWeather();
while not iar.IsCompleted do
begin
{ Amuse the user with "music on hold" while we wait }
millis := playMessage('strumming');
{ Wait for the request to complete, the music to stop,
or for the user to hang up. When the music stops we
just play it again but we could count the iterations
of the loop to enforce a time out. }
wait(iar.AsyncWaitHandle, millis);
end;
// When the request completes we fetch the data and build the forecast
CompleteRequest();
// That done we kill the music, add a bit of silence
// and then deliver the forecast to the caller
stopPlaying();
wait(500);
syn.speak(weather);
// While speaking we add an entry to the call detail records
cdrStatusMessage(0, zip);
cdrStatusMessage(1, weather);
// Then we wait for the forecast to be completely spoken
syn.wait();
end;
end;
{ Be polite and say goodbye before hanging up }
syn.speak('Good bye.');
syn.wait();
except
{ Nothing serious here; caller hung up }
on t : NetClientCallTermination do
begin
Writeln(t.Message);
CancelRequest();
end;
{ This might just be serious }
on e : Exception do
begin
Writeln(e.Message);
CancelRequest();
end;
end;
end;
{ We use this hash table to translate state abbreviations we get from the web
service to more easily pronounceable stuff. }
class procedure TDelphiWeatherDTMF.BuildStatesTable();
begin
states := Hashtable.Create();
states.Add('AL', 'Alabama');
states.Add('AK', 'Alaska');
states.Add('AZ', 'Arizona');
states.Add('AR', 'Arkansas');
states.Add('CA', 'California');
states.Add('CO', 'Colorado');
states.Add('CT', 'Connecticut');
states.Add('DE', 'Delaware');
states.Add('DC', 'D C');
states.Add('FL', 'Florida');
states.Add('GA', 'Georgia');
states.Add('HI', 'Hawaii');
states.Add('ID', 'Idaho');
states.Add('IL', 'Illinois');
states.Add('IN', 'Indiana');
states.Add('IA', 'Iowa');
states.Add('KS', 'Kansas');
states.Add('KY', 'Kentucky');
states.Add('LA', 'Louisiana');
states.Add('ME', 'Maine');
states.Add('MD', 'Maryland');
states.Add('MA', 'Massachusetts');
states.Add('MI', 'Michigan');
states.Add('MN', 'Minnesota');
states.Add('MS', 'Mississippi');
states.Add('MO', 'Missouri');
states.Add('MT', 'Montana');
states.Add('NE', 'Nebraska');
states.Add('NV', 'Nevada');
states.Add('NH', 'New Hampshire');
states.Add('NJ', 'New Jersey');
states.Add('NM', 'New Mexico');
states.Add('NY', 'New York');
states.Add('NC', 'North Carolina');
states.Add('ND', 'North Dakota');
states.Add('OH', 'Ohio');
states.Add('OK', 'Oklahoma');
states.Add('OR', 'Oregon');
states.Add('PA', 'Pennsylvania');
states.Add('PR', 'Puerto Rico');
states.Add('RI', 'Rhode Island');
states.Add('SC', 'South Carolina');
states.Add('SD', 'South Dakota');
states.Add('TN', 'Tennessee');
states.Add('TX', 'Texas');
states.Add('UT', 'Utah');
states.Add('VT', 'Vermont');
states.Add('VA', 'Virginia');
states.Add('WA', 'Washington');
states.Add('WV', 'West Virginia');
states.Add('WI', 'Wisconsin');
states.Add('WY', 'Wyoming');
end;
{ Access a web service to retrieve the weather for the ZIP code }
procedure TDelphiWeatherDTMF.RequestWeather();
var
query : string;
begin
{ Complete the query string and use XML HTTP to send it }
query := System.String.Create(zip);
query := baseQuery + query;
req := WebRequest.CreateDefault( Uri.Create(query) );
iar := req.BeginGetResponse(nil, nil);
end;
{ When the asynchronous HTTP transation completes we fetch the results }
procedure TDelphiWeatherDTMF.CompleteRequest();
var
doc : XmlDocument;
mgr : XmlNamespaceManager;
msg : StringBuilder;
city : string;
temp : string;
wind : string;
isOpen : Boolean;
outlook : string;
begin
doc := nil;
mgr := nil;
resp := nil;
isOpen := false;
weather := nil;
try
resp := HttpWebResponse ( req.EndGetResponse(iar) );
try
isOpen := true;
// The response from the web service is XML so load it into a document
doc := XmlDocument.Create();
doc.Load( resp.GetResponseStream() );
// Get a namespace manager and add the namespace
mgr := XmlNamespaceManager.Create(doc.NameTable);
mgr.AddNamespace(nameSpaceName, nameSpaceUri);
// Then pull the city, temperature, current condition and wind speed from it
city := GetCity(doc, mgr);
temp := GetTemperature(doc, mgr);
wind := GetWind(doc, mgr);
outlook := GetOutlook(doc, mgr);
// We take those bits of information to build a two sentence forecast
msg := StringBuilder.Create();
msg.Append('In ');
msg.Append(city);
msg.Append(', the weather is ');
msg.Append(outlook);
msg.Append(' with a temperature of ');
msg.Append(temp);
msg.Append('. The winds are ');
msg.Append(wind);
msg.Append('.');
weather := msg.ToString();
except
on ioe : InvalidOperationException do
isOpen := false;
on e : Exception do
Console.WriteLine(e.Message);
end;
// Make sure we close the connection when we are done
finally
if isOpen then
resp.Close()
end;
// If we failed to build a forecast we'll offer an apology instead
if weather = nil then
weather := regrets;
end;
{ We will cancel the outstanding web service request if the user hangs
up of if an exception occurs }
procedure TDelphiWeatherDTMF.CancelRequest();
begin
try
if req <> nil then
begin
req.Abort();
CompleteRequest();
end;
except
on e : Exception do
Console.WriteLine( e.Message );
end;
end;
{ Pull the city from the document }
function TDelphiWeatherDTMF.GetCity(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
var
city : string;
temp1 : string;
temp2 : string;
node : XmlNode;
begin
// The city and the state reside in the same node ...
node := doc.SelectSingleNode('//channel/yweather:location', mgr);
// ... as distinct attributes
temp1 := node.Attributes.GetNamedItem('city').InnerText;
temp2 := node.Attributes.GetNamedItem('region').InnerText;
// Expand the state abbreviation if we know it ...
if ( states.Contains(temp2) ) then
city := temp1 + ' ' + states.Item[temp2].ToString()
// ... or take it as is if we don't
else
city := temp1 + ' ' + temp2;
result := city;
end;
{ Pull the wind speed and direction from the document }
function TDelphiWeatherDTMF.GetWind(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
var
node : XmlNode;
temp1 : string;
temp2 : string;
degrees : Integer;
begin
node := doc.SelectSingleNode('//channel/yweather:wind', mgr);
temp1 := node.Attributes.GetNamedItem('direction').InnerText;
temp2 := node.Attributes.GetNamedItem('speed').InnerText;
degrees := System.Convert.ToInt32(temp1);
result := 'from the ' + Direction(degrees) + ' at ' + temp2 + ' miles per hour';
end;
{ Pull the current condition from the document }
function TDelphiWeatherDTMF.GetOutlook(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
var
node : XmlNode;
begin
node := doc.SelectSingleNode('//channel/item/yweather:condition', mgr);
result := node.Attributes.GetNamedItem('text').InnerText;
end;
{ Pull the current temperature from the document }
function TDelphiWeatherDTMF.GetTemperature(doc : XmlDocument; mgr : XmlNamespaceManager) : string;
var
temp : string;
node : XmlNode;
begin
node := doc.SelectSingleNode('//channel/item/yweather:condition', mgr);
temp := node.Attributes.GetNamedItem('temp').InnerText;
result := temp + ' degrees Fahrenheit';
end;
{ Translates a numeric wind heading to compass direction }
function TDelphiWeatherDTMF.Direction(num : integer) : string;
begin
if num <= 11 then
result := 'north'
else if num <= 33 then
result := 'north northeast'
else if num <= 56 then
result := 'northeast'
else if num <= 78 then
result := 'east northeast'
else if num <= 101 then
result := 'east'
else if num <= 123 then
result := 'east southeast'
else if num <= 146 then
result := 'southeast'
else if num <= 168 then
result := 'south southeast'
else if num <= 191 then
result := 'south'
else if num <= 213 then
result := 'south southwest'
else if num <= 236 then
result := 'southwest'
else if num <= 258 then
result := 'west southwest'
else if num <= 281 then
result := 'west'
else if num <= 303 then
result := 'west northwest'
else if num <= 326 then
result := 'northwest'
else if num <= 348 then
result := 'north northwest'
else
result := 'north';
end;
end.