Question

面对Python中似乎是一个流行的模块/函数（getimageinfo.py）的错误。想要获得图像大小而不下载它们。但是，遇到以下错误：

>>> import getimageinfo
>>> import urllib2
>>> imgdata = urllib2.urlopen('https://cdn.programiz.com/sites/tutorial2program/files/python-modules.jpg')
>>> image_type,width,height = getimageinfo.getImageInfo(imgdata)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "getimageinfo.py", line 61, in getImageInfo
    width = int(w)
UnboundLocalError: local variable 'w' referenced before assignment
>>>

错误似乎来自代码的这一部分：

# handle JPEGs
elif (size >= 2) and data.startswith('\377\330'):
    content_type = 'image/jpeg'
    jpeg = StringIO.StringIO(data)
    jpeg.read(2)
    b = jpeg.read(1)
    try:
        while (b and ord(b) != 0xDA):
            while (ord(b) != 0xFF): b = jpeg.read(1)
            while (ord(b) == 0xFF): b = jpeg.read(1)
            if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
                jpeg.read(3)
                h, w = struct.unpack(">HH", jpeg.read(4))
                break
            else:
                jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
            b = jpeg.read(1)
        width = int(w)
        height = int(h)
    except struct.error:
        pass
    except ValueError:
        pass

似乎没有其他人面临该模块的错误（至少没有人报告过Stackoverflow或其他论坛）。我如何解决它？我想得到

                h, w = struct.unpack(">HH", jpeg.read(4))

以外的行如果＆＃39;声明，但不知道在图像具有奇怪属性的情况下它会有多严重。（新编码）

Answer 1

如果条件w为(ord(b) >= 0xC0 and ord(b) <= 0xC3)，您尚未声明False的默认值，我可以添加两条注释行

    while (b and ord(b) != 0xDA):
        while (ord(b) != 0xFF): b = jpeg.read(1)
        while (ord(b) == 0xFF): b = jpeg.read(1)
        # HERE YOU NEED SET VALUE for w and h
        if (ord(b) >= 0xC0 and ord(b) <= 0xC3):
            jpeg.read(3)
            h, w = struct.unpack(">HH", jpeg.read(4))
            break
        else:
            # Or HERE YOU NEED SET VALUE for w and h
            jpeg.read(int(struct.unpack(">H", jpeg.read(2))[0])-2)
        b = jpeg.read(1)
    width = int(w)
    height = int(h)

Python getimageinfo.py:UnboundLocalError：local variable＆＃39; w＆＃39;在转让之前引用

1 个答案: