写入 NamedTemporaryFile 静默失败；将 Curl cookie jar 转换为 Requests cookie

Question

我正在尝试获取 Curl 吐出的 Netscape HTTP Cookie 文件并将其转换为 Requests 库可以使用的 Cookiejar。我的 Python 脚本中有 netscapeCookieString 作为变量，如下所示：

# Netscape HTTP Cookie File
# https://curl.haxx.se/docs/http-cookies.html
# This file was generated by libcurl! Edit at your own risk.

.miami.edu  TRUE    /   TRUE    0   PS_LASTSITE https://canelink.miami.edu/psc/PUMI2J/

由于我不想自己解析 cookie 文件，我想使用cookielib。可悲的是，这意味着我必须写入磁盘，因为 cookielib.MozillaCookieJar() 不会将字符串作为输入：它必须采用文件。

所以我正在使用NamedTemporaryFile（无法让SpooledTemporaryFile 工作；如果可能，我再次希望在内存中完成所有这些操作）。

tempCookieFile = tempfile.NamedTemporaryFile()

# now take the contents of the cookie string and put it into this in memory file
# that cookielib will read from. There are a couple quirks though. 
for line in netscapeCookieString.splitlines():

    # cookielib doesn't know how to handle httpOnly cookies correctly
    # so we have to do some pre-processing to make sure they make it into
    # the cookielib. Basically just removing the httpOnly prefix which is honestly
    # an abuse of the RFC in the first place. note: httpOnly actually refers to
    # cookies that javascript can't access, as in only http protocol can
    # access them, it has nothing to do with http vs https. it's purely 
    # to protect against XSS a bit better. These cookies may actually end up
    # being the most critical of all cookies in a given set.
    # https://stackoverflow.com/a/53384267/2611730
    if line.startswith("#HttpOnly_"):
        # this is actually how the curl library removes the httpOnly, by doing length
        line = line[len("#HttpOnly_"):]

    tempCookieFile.write(line)

tempCookieFile.flush()

# another thing that cookielib doesn't handle very well is 
# session cookies, which have 0 in the expires param
# so we have to make sure they don't get expired when they're
# read in by cookielib
# https://stackoverflow.com/a/14759698/2611730
print tempCookieFile.read()
cookieJar = cookielib.MozillaCookieJar(tempCookieFile.name)
cookieJar.load(ignore_expires=True)
pprint.pprint(cookieJar)

但这是踢球者，这不起作用！

print tempCookieFile.read() 打印一个空行。

因此，pprint.pprint(cookieJar) 打印出一个空的 cookie 罐。

我很容易在我的 Mac 上重现这个：

>>> import tempfile
>>> tempCookieFile = tempfile.NamedTemporaryFile()
>>> tempCookieFile.write("hey")
>>> tempCookieFile.flush()
>>> print tempCookieFile.read()

>>>

我怎样才能真正写信给NamedTemporaryFile？

Answer 1

在您写入文件后，指向该文件的指针指向写入数据之后的位置（在您的情况下为文件结尾），因此当您读取它时返回一个空字符串（文件结尾后不再有数据）阅读前先求0

>>> import tempfile
>>> tempCookieFile = tempfile.NamedTemporaryFile()
>>> tempCookieFile.write("hey")
>>> tempCookieFile.seek(0)
>>> print(tempCookieFile.read())