如何通过 EXIF / JFIF 签名检测 JPEG 文件？

Question

几天前，我最后一个朋友 (@emcconville) 帮我编写了 "Recover every JPEG files in a single file" 的脚本。现在我意识到这个程序只适用于 "JFIF" 标准的图像，不能检索 "EXIF" 标准的图像（数码相机拍摄的图像）。

如何修改程序使其在图像中也能识别Exif标准？我不熟悉 Python，也不知道它的威力。

谢谢

import struct

with open('src.bin', 'rb') as f:
    # Calculate file size.
    f.seek(0, 2)
    total_bytes = f.tell()
    # Rewind to beging.
    f.seek(0)
    file_cursor = f.tell()
    image_cursor = 0

    while file_cursor < total_bytes:
        # Can for start of JPEG.
        if f.read(1) == b"\xFF":
            if f.read(3) == b"\xD8\xFF\xE0":
                print("JPEG FOUND!")
                # Backup and find the size of the image
                f.seek(-8, 1)
                payload_size = struct.unpack('<I', f.read(4))[0]
                # Write image to disk
                d_filename = 'image{0}.jpeg'.format(image_cursor)
                with open(d_filename, 'wb') as d:
                    d.write(f.read(payload_size))
                image_cursor += 1
        file_cursor = f.tell()

Answer 1

EXIF files have a marker of 0xffe1, JFIF files have a marker of 0xffe0. So all code that relies on 0xffe0 to detect a JPEG file will miss all EXIF files. (from here)

所以改变一下

if f.read(3) == b"\xD8\xFF\xE0":

到

if f.read(3) == b"\xD8\xFF\xE1":

如果您想检查这两种情况，请不要再那样使用 .read()。取而代之的是

x = f.read(3)
if x in (b"\xD8\xFF\xE0", b"\xD8\xFF\xE1"):

如何通过 EXIF / JFIF 签名检测 JPEG 文件？

How can I detect JPEG files by their EXIF / JFIF signature?

python

exif

jfif