字节明智的修改在JPG图像的特定范围内（被视为二进制对象）
我正在测试在.jpg文件的末尾编写数据。众所周知，所有.jpg文件以FFD8开头，并以FFD9结束。利用这个事实，我成功地写了“ Hello World！”在我的.jpg文件的末尾，带有看起来像这样的函数：
def writte_at_the_end_of_jpg_fct (img_path:str, msg:str):
with open(img_path, 'ab') as fimg:
fimg.write(b"Hello World!")
确实我得到了：
但是现在我该怎么做才能仅删除文件末尾添加的数据（这意味着“ Hllo World！”
我尝试了这一点：
def erase_data_in_img_fct(img_jpg_file_path: str) -> None:
with open(img_jpg_file_path, 'rb') as fimg:
content = fimg.read()
offset = content.index(bytes.fromhex('FFD9'))
end_i = fimg.seek(offset + 2)
with open(img_jpg_file_path, 'ab') as fimg:
fimg = fimg[0:end_i]
但是它不起作用，我获取此错误：
typeError：'_io.bufferedwriter'对象不可订阅
我在网络上搜索了很多时间，答案是我的问题，但找不到。
谢谢
I am testing to write data at the end of a .jpg file. As i know all the .jpg files begin by FFD8 and end by FFD9. Using that fact i succeeded in writting "Hello World!" at the end of my .jpg file with a function that looks like this:
def writte_at_the_end_of_jpg_fct (img_path:str, msg:str):
with open(img_path, 'ab') as fimg:
fimg.write(b"Hello World!")
And Indeed i get:
But now how can i do to remove only the data that i ve added at the end of the file (that means "Hllo World!"
I ve tried this:
def erase_data_in_img_fct(img_jpg_file_path: str) -> None:
with open(img_jpg_file_path, 'rb') as fimg:
content = fimg.read()
offset = content.index(bytes.fromhex('FFD9'))
end_i = fimg.seek(offset + 2)
with open(img_jpg_file_path, 'ab') as fimg:
fimg = fimg[0:end_i]
But it didn't work, i get this error:
TypeError: '_io.BufferedWriter' object is not subscriptable
I have searched a lot of time on the web an answer to my problem and didn't found it.
Thank you
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您应该使用 bytes.rindex ，因为
> code>> code>> FFD9字节可能在文件中多次发生：You should use bytes.rindex instead because the
ffd9bytes may occur multiple times in the file: