private bool ValidateMessageMarkdown(TelegramMessage message)
{
// Validate: *even is ok* and reject odd numbers of '*'
if (!Regex.IsMatch(message.Text, @"^[^*]*(\*[^*]*\*[^*]*)*$"))
{
return(false);
}
// Validate: _even is ok_ and reject odd numbers of '_'
if (!Regex.IsMatch(message.Text, @"^[^_]*(_[^_]*_[^_]*)*$"))
{
return(false);
}
// Validate: [inline URL](url)
// Validate: [inline mention of a user](tg://user?id=123456789)
// Validate: `inline fixed-width code`
if (!Regex.IsMatch(message.Text, @"^[^(`)]*(`[^(`)]*`[^(`)]*)*$"))
{
return(false);
}
// Validate:
// ```block_language
// pre - formatted fixed-width code block
// ```
if (!Regex.IsMatch(message.Text, @"^[^(```)]*(```[^(```)]*```[^(```)]*)*$"))
{
return(false);
}
return(true); // Assume valid if we passed all tests above.
}
public async Task <HttpResponseMessage> PostAsync(TelegramMessage message, string chatId)
{
string json;
// If the message type is 'Plain', the 'parse_mode' key CANNOT be present at all,
// else the Telegram API will attempt to parse the message string as a MarkDown.
if (message.ParseMode == Client.TelegramParseModeTypes.Plain ||
!ValidateMessage(message))
{
var payload = new
{
chat_id = chatId,
text = message.Text
};
json = JsonConvert.SerializeObject(value: payload);
}
else
{
var payload = new
{
chat_id = chatId,
text = message.Text,
parse_mode = message.ParseMode.ToString().ToLower()
};
json = JsonConvert.SerializeObject(value: payload);
}
var response = await _httpClient.PostAsync(
requestUri : _apiUrl,
content : new StringContent(
content: json, encoding: Encoding.UTF8, mediaType: "application/json"));
return(response);
}
private bool ValidateMessageHtml(TelegramMessage message)
{
// Validate the cases where Telegram returns 'BadRequest'. These cases
// really need to be tested with real data because it's unclear what will
// trigger an error from Telegram.
return(true); // Assume everything is valid for now.
}
public async Task <HttpResponseMessage> PostAsync(TelegramMessage message, string chatId)
{
var payload = new
{
chat_id = chatId,
text = message.Text,
parse_mode = "markdown"
};
var json = JsonConvert.SerializeObject(value: payload);
var response = await _httpClient.PostAsync(requestUri : _apiUrl,
content : new StringContent(content: json, encoding: Encoding.UTF8, mediaType: "application/json"));
return(response);
}
/// <summary>
/// These methods should be extended to validate all the cases where Telegram
/// will reject a 'Markdown' or 'Html' formatted string as 'BadRequest'.
/// </summary>
/// <example>
/// Message "*This is rejected" is rejected by Telegram as an invalid
/// markdown because it has an odd number of asterisks, instead of being ignored
/// as it really should.
/// </example>
/// <param name="message"></param>
/// <returns>
/// True: message is valid for the parse mode type.
/// False: invalid and should probably be handled as normal text.
/// </returns>
private bool ValidateMessage(TelegramMessage message)
{
switch (message.ParseMode)
{
case Client.TelegramParseModeTypes.Html:
return(ValidateMessageHtml(message));
case Client.TelegramParseModeTypes.Markdown:
return(ValidateMessageMarkdown(message));
case Client.TelegramParseModeTypes.Plain:
break;
}
return(true); // Is valid
}
protected void SendMessage(string token, string chatId, TelegramMessage message)
{
SelfLog.WriteLine($"Trying to send message to chatId '{chatId}': '{message}'.");
var telegramClient = TelegramClientFactory.CreateClient(token, proxy);
var sendMessageTask = telegramClient.PostAsync(message: message, chatId: chatId);
Task.WaitAll(sendMessageTask);
var sendMessageResult = sendMessageTask.Result;
if (sendMessageResult != null)
{
SelfLog.WriteLine($"Message sent to chatId '{chatId}': '{sendMessageResult.StatusCode}'.");
}
}
protected void SendMessage(string token, string chatId, TelegramMessage message)
{
SelfLog.WriteLine($"Trying to send message to chatId '{chatId}': '{message}'.");
var client = new TelegramClient(botToken: token, timeoutSeconds: 5);
var sendMessageTask = client.PostAsync(message: message, chatId: chatId);
Task.WaitAll(sendMessageTask);
var sendMessageResult = sendMessageTask.Result;
if (sendMessageResult != null)
{
SelfLog.WriteLine($"Message sent to chatId '{chatId}': '{sendMessageResult.StatusCode}'.");
}
}