Python Telegram Bot sendPhoto Method Throws ASCII Codec Error

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1

I’m working with a Telegram bot using Python 2.7 and running into encoding issues when trying to send images. When I attempt to upload a photo from my local directory, I keep getting a UnicodeDecodeError.

Here’s the code I’m using to send the image:

telegram_bot.send_photo(chat_message.chat_id, photo=open(picture.file_path, 'rb'))

The picture.file_path contains the complete path to a JPEG image file. However, when this code runs, I get this error:

UnicodeDecodeError: 'ascii' codec can't decode byte 0xff in position 0: ordinal not in range(128)

I tried different approaches like opening the file with specific encoding:

with io.open(picture.file_path, 'r', encoding='utf8') as image_file:
    telegram_bot.send_photo(chat_message.chat_id, photo=image_file.read())

But this just creates different encoding problems. The error seems to happen when the library tries to process the binary image data as text. Has anyone faced this issue before? What’s the proper way to handle image file encoding when sending photos through the Telegram bot API?

2

This happens because you’re mixing binary and text operations. Your second approach opens the image file in text mode with UTF-8 encoding, but JPEG files are binary data - they shouldn’t be decoded as text. I hit this exact issue when migrating an old bot from Python 2.7. You need to work with binary data consistently throughout. Try this:

with open(picture.file_path, 'rb') as photo_file:
    telegram_bot.send_photo(chat_message.chat_id, photo=photo_file)

Pass the file object directly instead of calling read() on it. This lets the Telegram library handle the binary data properly without trying to decode ASCII. Also, upgrade from Python 2.7 if you can - it handles Unicode way better by default and prevents these encoding headaches.

3

python 2.7 is notorious for this. ur first code looks right, but maybe somethings off with the file path? try printing the file_path variable and check for non-ascii chars in the filename or directory. thatll make the decoder choke before it even reads the img data.

4

I hit this same issue with file paths that had special characters. The problem might not be your file opening code - it’s probably the file path encoding that’s messed up. Try encoding the path first:

file_path = picture.file_path.encode('utf-8')
with open(file_path, 'rb') as photo:
    telegram_bot.send_photo(chat_message.chat_id, photo=photo)

Also check if your picture.file_path is actually a string or unicode object. In Python 2.7, use type(picture.file_path) to find out. If it’s unicode, convert it to a byte string first. I’ve seen paths get corrupted during file system operations, especially on Windows with non-English folder names.