Using Telegram Bot API to upload a valid photo (pic.png) results in error 400 for unsupported extension. Code sample below:
using (var imgStream = File.Open("pic.png", FileMode.Open))
{
var response = await client.UploadImageAsync(chatId, new FilePacket("pic", imgStream));
}
Any insights?
I encountered a similar issue when working with the Telegram Bot API. In my case, the problem wasn’t with the file itself but with how the file packet was set up. I discovered that explicitly naming the parameter to what Telegram expects, which is typically ‘photo’, rather than a custom name like ‘pic’, resolved the error. There was also a chance that a mismatch in the version of the library was causing some inconsistencies, so updating the package helped. Additionally, reviewing the API documentation closely for any changes in parameter naming conventions can prevent these types of issues.
I encountered a similar issue recently when developing a Telegram bot. The error message was misleading at first, as it suggested a problem with the file extension when, in fact, the issue was related to parameter configuration. I found that explicitly labeling the file parameter as ‘photo’ in my request was essential. Also, I ensured that the file stream was properly managed and that the file’s content type was correctly recognized. It turned out that a minor misalignment in parameter naming was enough to trigger the 400 error.
hey, try setting the file param as ‘photo’. i had weird issues until i updated my library version too. sometimes an outdated version messes up filetype recognition. give that a shot!
I experienced a similar issue recently and discovered that the problem was not with the file’s extension at all but with how the file stream was managed by the library. I eventually determined that the file stream was not properly initiated at the time of calling the upload, causing the API to misinterpret the file content. After diving deeper into the documentation, I realized that ensuring the stream was freshly opened and correctly processed before the call made a difference. I also checked that the library version used handled the MIME types as expected, which ultimately resolved the problem.
In my experience, the error can sometimes be attributed to incomplete file metadata passed to the Telegram API. I once encountered this issue because the file packet did not include a proper fileName, causing Telegram to struggle in determining the correct MIME type. I solved it by explicitly setting the fileName to ‘pic.png’ when constructing the FilePacket, ensuring that the API received both the correct parameter name and metadata. Additionally, verifying that the stream remained open during the request resolved some intermittent issues in similar cases. Checking these factors may help address your situation.