8.6 KiB
- How to get picture?
- How to send photos?
- How do I send photos by file_id?
- How to use custom keyboards?
- How can I run my bot?
- How can I compile my project?
How to download photo?
To download a picture (or any other file), you will need the file_path of the file. Let start by finding the photo we want to download, the following method will extract the PhotoSize from a photo sent to the bot (in our case, we are taken the bigger size of those provided):
public PhotoSize getPhoto(Update update) {
// Check that the update contains a message and the message has a photo
if (update.hasMessage() && update.getMessage().hasPhoto()) {
// When receiving a photo, you usually get different sizes of it
List<PhotoSize> photos = update.getMessage().getPhoto();
// We fetch the bigger photo
return photos.stream()
.sorted(Comparator.comparing(PhotoSize::getFileSize).reversed())
.findFirst()
.orElse(null);
}
// Return null if not found
return null;
}
Once we have the photo we have to options: The file_path is already present or we need to get it, the following method will handle both of them and return the final file_path:
public String getFilePath(PhotoSize photo) {
Objects.requireNonNull(photo);
if (photo.hasFilePath()) { // If the file_path is already present, we are done!
return photo.getFilePath();
} else { // If not, let find it
// We create a GetFile method and set the file_id from the photo
GetFile getFileMethod = new GetFile();
getFileMethod.setFileId(photo.getFileId());
try {
// We execute the method using AbsSender::getFile method.
File file = getFile(getFileMethod);
// We now have the file_path
return file.getFilePath();
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
return null; // Just in case
}
Now that we have the file_path we can download it:
public java.io.File downloadPhotoByFilePath(String filePath) {
try {
// Download the file calling AbsSender::downloadFile method
return downloadFile(filePath);
} catch (TelegramApiException e) {
e.printStackTrace();
}
return null;
}
The returned java.io.File object will be your photo
How to send photos?
There are several method to send a photo to an user using sendPhoto method: With a file_id, with an url or uploading the file. In this example, we assume that we already have the chat_id where we want to send the photo:
public void sendImageFromUrl(String url, String chatId) {
// Create send method
SendPhoto sendPhotoRequest = new SendPhoto();
// Set destination chat id
sendPhotoRequest.setChatId(chatId);
// Set the photo url as a simple photo
sendPhotoRequest.setPhoto(url);
try {
// Execute the method
sendPhoto(sendPhotoRequest);
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
public void sendImageFromFileId(String fileId, String chatId) {
// Create send method
SendPhoto sendPhotoRequest = new SendPhoto();
// Set destination chat id
sendPhotoRequest.setChatId(chatId);
// Set the photo url as a simple photo
sendPhotoRequest.setPhoto(fileId);
try {
// Execute the method
sendPhoto(sendPhotoRequest);
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
public void sendImageUploadingAFile(String filePath, String chatId) {
// Create send method
SendPhoto sendPhotoRequest = new SendPhoto();
// Set destination chat id
sendPhotoRequest.setChatId(chatId);
// Set the photo file as a new photo (You can also use InputStream with a method overload)
sendPhotoRequest.setNewPhoto(new File(filePath));
try {
// Execute the method
sendPhoto(sendPhotoRequest);
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
How to send photo by its file_id?
In this example we will check if user sends to bot a photo, if it is, get Photo's file_id and send this photo by file_id to user.
// If it is a photo
if (update.hasMessage() && update.getMessage().hasPhoto()) {
// Array with photos
List<PhotoSize> photos = update.getMessage().getPhoto();
// Get largest photo's file_id
String f_id = photos.stream()
.sorted(Comparator.comparing(PhotoSize::getFileSize).reversed())
.findFirst()
.orElse(null).getFileId();
// Send photo by file_id we got before
SendPhoto msg = new SendPhoto()
.setChatId(update.getMessage().getChatId())
.setPhoto(f_id)
.setCaption("Photo");
try {
sendPhoto(msg); // Call method to send the photo
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
How to use custom keyboards?
Custom keyboards can be appended to messages using the setReplyMarkup. In this example, we will build a simple ReplyKeyboardMarkup with two rows and three buttons per row, but you can also use other types like ReplyKeyboardHide, ForceReply or InlineKeyboardMarkup:
public void sendCustomKeyboard(String chatId) {
SendMessage message = new SendMessage();
message.setChatId(chatId);
message.setText("Custom message text");
// Create ReplyKeyboardMarkup object
ReplyKeyboardMarkup keyboardMarkup = new ReplyKeyboardMarkup();
// Create the keyboard (list of keyboard rows)
List<KeyboardRow> keyboard = new ArrayList<>();
// Create a keyboard row
KeyboardRow row = new KeyboardRow();
// Set each button, you can also use KeyboardButton objects if you need something else than text
row.add("Row 1 Button 1");
row.add("Row 1 Button 2");
row.add("Row 1 Button 3");
// Add the first row to the keyboard
keyboard.add(row);
// Create another keyboard row
row = new KeyboardRow();
// Set each button for the second line
row.add("Row 2 Button 1");
row.add("Row 2 Button 2");
row.add("Row 2 Button 3");
// Add the second row to the keyboard
keyboard.add(row);
// Set the keyboard to the markup
keyboardMarkup.setKeyboard(keyboard);
// Add it to the message
message.setReplyMarkup(keyboardMarkup);
try {
// Send the message
sendMessage(message);
} catch (TelegramApiException e) {
e.printStackTrace();
}
}
How can I run my bot?
You don't need to spend a lot of money into hosting your own telegram bot. Basically, there are two options around how to host:
- Hosting on your own hardware. It can be a Mini-PC like a Raspberry Pi. The costs for the hardware (~35€) and annual costs for power (~7-8€) are low. Keep in mind that your internet connection might be limited and a Mini-Pc is not ideal for a large users base.
- Run your bot in a Virtual Server/dedicated root server. There are many hosters out there that are providing cheap servers that fit your needs. The cheapest one should be openVZ-Containers or a KVM vServer. Example providers are Hetzner, DigitalOcean, (are providing systems that have a high availability but cost's a bit more) and OVH
How can I compile my project?
This is just one way, how you can compile it (here with maven). The example below below is compiling the TelegramBotsExample repo.
