Python-变量未定义，但我认为是

Question

I am pulling images from the Internet Archive as a test of some python code and I am incorporating the requests module. My code is as follows: (note, not the entire code, just the relevant section)

    image_results = []
    image_hashes = []
    session = requests.Session()


    for image in image_list:
        if txtUrl not in image:
            continue
    try:
        self.rslBox.AppendText("[v] Downloading %s" % image + "\n")
        self.rslBox.Refresh()
        response = session.get(image)
    except:
        self.rslBox.AppendText("[!] Failed to download: %s" % image + "\n")
        self.rslBox.Refresh()
#        continue

    if "image" in response.headers['content-type']:

        sha1 = hashlib.sha1(response.content).hexadigest()

        if sha1 not in image_hashes:
            image_hashes.append(sha1)
            image_path = "WayBackImages/%s-%s" % (sha1.image.split("/")[-1])

            with open(image_path, "wb") as fd:
                fd.write(response.content)

            self.rslBox.AppendText("[*] Saved %s" % images + "\n")
            self.rslBox.Refresh()

            info = pyexifinfo.get_json(image_path)
            info[0]['ImageHash'] = sha1
            image_results.append(info[0])

            image_results_json = json.dumps(image_results)
            data_frame = pandas.read_json(image_results_json)
            csv = data_frame.to_csv('results.csv')

    self.rslBox.AppendText("[*] Finished writing CSV to results.csv" + '\n')
    self.rslBox.Refresh()
    return

When I run my code, I get the following message:

Traceback (most recent call last):
File "C:\eclipse-workspace\test\tabbedPage.py", line 136, in OnSearch
if "image" in response.headers['content-type']:
NameError: name 'response' is not defined

But response is defined in the try statement - or so I would think. It only complains on the if "image" section - why??

I am new to python and I am using python3.6 and pydev with Eclipse. Thanks!

Answer 1

Something inside your try failed. Your except caught it handle the error but since there is no raise in it, it continues execution, but response is not set.

Answer 2

It's because you are declaring response in the try block. If the exception gets thrown then response is not declared.

A work around for this would be putting the code that relies on response being declared into that try block.