Want to send a message to a Teams channel from your Delphi Application?
It is easy – simply post the message to your Teams channel’s WebHook URL.
Update – added Uwe Raabe’s TRESTClient version.
Here is the low down basics of how to do it from Delphi. You simply do a http post with a preformatted Json string.
unit O365WebHook;
// Lars Fosdal, 2020 OCT 16
// Simple example without error handling
interface
uses
System.Classes, System.SysUtils, System.Json, Rest.Json,
IDGlobal, IdHTTP, IdIOHandler, IdSSL, IdSSLOpenSSL;
type
TWebHookMessage = class
end;
/// <summary> See https://docs.microsoft.com/en-us/microsoftteams/platform/webhooks-and-connectors/how-to/connectors-using
/// for examples of how to structure the json for creating advanced formats</summary>
TSimpleText = class(TWebHookMessage)
private
FText: String;
public
property Text: String read FText write FText;
constructor Create(const aText: string);
end;
type
TWebHook = class
private
FHTTP: TIdHTTP;
FURL: string;
protected
property HTTP: TIdHTTP read FHTTP;
public
constructor Create(const aURL: string = '');
destructor Destroy; override;
procedure Post(const aJson: string);
procedure PostMessage(const aMsg: TWebhookMessage);
property URL:String read FURL write FURL;
end;
implementation
{ TWebHook }
constructor TWebHook.Create(const aURL: string);
begin
FURL := aURL;
// Remember that you need libeay32.dll and ssleay32.dll in the path for https to work
FHTTP := TIdHTTP.Create(nil);
HTTP.Request.ContentType := 'application/json';
HTTP.Request.ContentEncoding := 'utf-8';
HTTP.Request.CacheControl := 'no-cache';
HTTP.HTTPOptions := HTTP.HTTPOptions - [hoForceEncodeParams] + [hoNoProtocolErrorException, hoWantProtocolErrorContent];
end;
destructor TWebHook.Destroy;
begin
FHTTP.Free;
inherited;
end;
procedure TWebHook.Post(const aJson: string);
var
ReqString: TStringList;
ResStream: TStringStream;
begin
ReqString := TStringList.Create;
try
try
ReqString.Text := aJson;
ResStream := TStringStream.Create;
try
// DebugOut('HTTP Post ' + ReqString.Text);
HTTP.Post(URL, ReqString, ResStream, IndyTextEncoding_UTF8);
// DebugOut('Response: ' + ResStream.DataString);
finally
ResStream.Free;
end;
except // HTTP Exception
on E: Exception
do begin
// DebugOutException(E, 'HTTP Post');
end;
end;
finally
ReqString.Free;
end;
end;
procedure TWebHook.PostMessage(const aMsg: TWebhookMessage);
begin
try
Post(
TJson.ObjectToJsonString(
aMsg,
[joIgnoreEmptyStrings, joIgnoreEmptyArrays, joDateIsUTC, joDateFormatISO8601]
)
);
finally
aMsg.Free;
end;
end;
{ TSimpleText }
constructor TSimpleText.Create(const aText: string);
begin
Text := aText;
end;
end.
How to use it. This is a very minimal example for a single text line.
procedure TestExampleToATeamsChannel;
var
Teams: TWebhook;
begin
Teams := TWebhook.Create('https:// ... YourLongWebHookURLHere ... ');
try
Teams.PostMessage(TSimpleText.Create('Hello from Delphi! :"{/=''æ}[øå] ÆØÅ'));
finally
Teams.Free;
end;
end;
Make sure to read up on throttling and other rules of engagement before you start spamming your Teams channels. See the MS article on WebHooks for more detail.
Update! Uwe Raabe did a refurbished version that eliminates Indy and the need for the the OpenSLL DLLs, and makes the code work cross platform!
unit O365WebHook;
// Lars Fosdal, 2020 OCT 16
// Simple example without error handling
// Uwe Raabe replaced Indy for TRESTClient, eliminating the need for the OpenSLL DLLS
interface
uses
System.Classes, System.SysUtils,
REST.Json, REST.Client, REST.Types;
type
TWebHookMessage = class
end;
/// <summary> See https://docs.microsoft.com/en-us/microsoftteams/platform/webhooks-and-connectors/how-to/connectors-using
/// for examples of how to structure the json for creating advanced formats</summary>
TSimpleText = class(TWebHookMessage)
private
FText: String;
public
property Text: String read FText write FText;
constructor Create(const aText: string);
end;
type
TWebHook = class
private
FClient: TRESTClient;
FRequest: TCustomRESTRequest;
FURL: string;
protected
property Client: TRESTClient read FClient;
property Request: TCustomRESTRequest read FRequest;
public
constructor Create(const aURL: string = '');
destructor Destroy; override;
function PostMessage(const aMsg: TWebhookMessage; aOwnsMsg: Boolean = False): Boolean;
property URL: string read FURL write FURL;
end;
implementation
{ TWebHook }
constructor TWebHook.Create(const aURL: string);
begin
inherited Create;
FURL := aURL;
FClient := TRESTClient.Create(nil);
FRequest := TCustomRESTRequest.Create(nil);
FRequest.Client := FClient;
end;
destructor TWebHook.Destroy;
begin
FRequest.Free;
FClient.Free;
inherited;
end;
function TWebHook.PostMessage(const aMsg: TWebhookMessage; aOwnsMsg: Boolean = False): Boolean;
begin
try
Request.Client.BaseURL := URL;
Request.Method := rmPOST;
Request.AddBody(aMsg);
Request.Execute;
Result := Request.Response.Status.Success;
finally
if aOwnsMsg then
aMsg.Free;
end;
end;
{ TSimpleText }
constructor TSimpleText.Create(const aText: string);
begin
inherited Create;
FText := aText;
end;
end.
There is a known issue with a workaround for Delphi 10.2.
Have fun!
Lars Fosdal 