疑难解答“TypeError：ord() 预期的长度为 1 的字符串，但找到了 int”

Posted 2023-02-16

【中文标题】疑难解答“TypeError：ord() 预期的长度为 1 的字符串，但找到了 int”

【英文标题】：Troubleshooting "TypeError: ord() expected string of length 1, but int found"

【发布时间】：2013-11-22 17:09:34

【问题描述】：

ERROR : TypeError: ord() expected string of length 1, but int found

我在编译程序时遇到此错误。

 File "C:\Users\Administrator\Desktop\tracer1.py", line 129, in <module>
    get_route("www.google.com")
  File "C:\Users\Administrator\Desktop\tracer1.py", line 85, in get_route
    d = build_packet()
  File "C:\Users\Administrator\Desktop\tracer1.py", line 62, in build_packet
    myChecksum = checksum(header + data)
  File "C:\Users\Administrator\Desktop\tracer1.py", line 28, in checksum
    thisVal = ord(str[count+1]) * 256 + ord(str[count])
**TypeError: ord() expected string of length 1, but int found**

程序是使用ICMP查找traceroute

from socket import *
import socket
import os
import sys
import struct
import time
import select
import binascii
import ctypes
ICMP_ECHO_REQUEST = 8
MAX_HOPS = 30
TIMEOUT = 2.0
TRIES = 2

# The packet that we shall send to each router along the path is the ICMP echo
# request packet, which is exactly what we had used in the ICMP ping exercise.
# We shall use the same packet that we built in the Ping exercise

ctypes.windll.shell32.IsUserAnAdmin()
print (ctypes.windll.shell32.IsUserAnAdmin())

def checksum(str):
    csum = 0
    countTo = (len(str) / 2) * 2
    count = 0

    while count < countTo:
        thisVal = ord(str[count+1]) * 256 + ord(str[count])
        csum = csum + thisVal
        csum = csum & 0xffffffff
        count = count + 2

    if countTo < len(str):
        csum = csum + ord(str[len(str) - 1])
        csum = csum & 0xffffffff

    csum = (csum >> 16) + (csum & 0xffff)
    csum = csum + (csum >> 16)
    answer = ~csum
    answer = answer & 0xffff
    answer = answer >> 8 | (answer << 8 & 0xff00)
    return answer

def build_packet():
    # In the sendOnePing() method of the ICMP Ping exercise ,firstly the header of our
    # packet to be sent was made, secondly the checksum was appended to the header and
    # then finally the complete packet was sent to the destination.

    # Make the header in a similar way to the ping exercise.
    # Header is type (8), code (8), checksum (16), id (16), sequence (16)
    myChecksum = 0
    pid = os.getpid() & 0xFFFF

    # Make a dummy header with a 0 checksum.
    # struct -- Interpret strings as packed binary data
    header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, myChecksum, pid, 1)
    #header = struct.pack("!HHHHH", ICMP_ECHO_REQUEST, 0, myChecksum, pid, 1)
    data = struct.pack("d", time.time())

    # Calculate the checksum on the data and the dummy header.
    # Append checksum to the header.
    myChecksum = checksum(header + data)    
    if sys.platform == 'darwin':
        myChecksum = socket.htons(myChecksum) & 0xffff
        #Convert 16-bit integers from host to network byte order.
    else:
        myChecksum = htons(myChecksum)

    packet = header + data
    return packet

def get_route(hostname):
    timeLeft = TIMEOUT
    for ttl in range(1,MAX_HOPS):
        for tries in range(TRIES):
            destAddr = socket.gethostbyname(hostname)
            #Fill in start
            # Make a raw socket named mySocket
            mySocket = socket.socket(AF_INET, SOCK_RAW, getprotobyname("icmp"))
            mySocket.bind(("", 12000));
            #Fill in end
            mySocket.setsockopt(socket.IPPROTO_IP, socket.IP_TTL, struct.pack('I', ttl))
            mySocket.settimeout(TIMEOUT)
            try:
                d = build_packet()
                mySocket.sendto(d, (hostname, 0))
                t = time.time()
                startedSelect = time.time()
                whatReady = select.select([mySocket], [], [], timeLeft)
                howLongInSelect = (time.time() - startedSelect)
                if whatReady[0] == []: # Timeout
                    print ("*    *    * Request timed out.")

                recvPacket, addr = mySocket.recvfrom(1024)
                print ("addr")
                timeReceived = time.time()
                timeLeft = timeLeft - howLongInSelect
                if timeLeft <= 0:
                    print ("*    *    * Request timed out.")
            except socket.timeout:
                continue
            else:
                #Fill in start
                # Fetch the icmp type from the IP packet
                print( struct.calcsize("bbHHhd"))
                request_code, request_type, checksum, packet_id, \
                    sequence, timeSent, data = struct.unpack("bbHHhd", recvPacket,0)
                #Fill in end

                if request_type == 11:
                    bytes = struct.calcsize("d")
                    timeSent = struct.unpack("d", recvPacket[28:28 + bytes])[0]
                    print (" %d   rtt=%.0f ms %s" % (ttl,(timeReceived -t)*1000, addr[0]))
                elif request_type == 3:
                    bytes = struct.calcsize("d")
                    timeSent = struct.unpack("d", recvPacket[28:28 + bytes])[0]
                    print (" %d   rtt=%.0f ms %s" % (ttl,(timeReceived -t)*1000, addr[0]))
                elif request_type == 0:
                    bytes = struct.calcsize("d")
                    timeSent = struct.unpack("d", recvPacket[28:28 + bytes])[0]
                    print (" %d   rtt=%.0f ms %s" % (ttl,(timeReceived -timeSent)*1000, addr[0]))
                    return
                else:
                    print ("error")
                    break
            finally:
                mySocket.close()

get_route("www.google.com")

【问题讨论】：

莫名其妙！如果可以重现，请尝试在checksum() 的开头打印repr(str)。

【参考方案1】：

您正在使用 Python 3 运行脚本，其中索引 bytes 对象返回一个整数：

>>> b"abc"[1]
98

删除ord() 调用。在这种情况下，它们是多余的。

【讨论】：

猜得好！如果他们正在运行 Python3，他们还应该更改 (len(str) / 2) * 2 以使用整数除法（或者简单地将 & 去掉最后一位）。

@TimPeters 你能解释清楚吗，有什么需要改变的。

@user2977469 使用 // 而不是 / 进行整数除法 - 它也适用于最新版本的 Python 2。

例如，在 Python 3 中，“3/2”是“1.5”。您的 checksum() 函数希望它返回整数 1（这发生在 Python 2 中）。最快的解决方法是将countTo = (len(str) / 2) * 2 中的/ 更改为//。如果不这样做，您的函数将无法正常处理奇数长度的字符串。

@user2977469：你删除了ord 电话吗？

【参考方案2】：

我今天遇到了类似类型的错误。我在此处添加了此答案以突出某些观察结果。这里要关注的主要 API 是 triple_des。如果输入是qqq，那么就会报错。如果输入为sMAC，则没有错误。有趣的是，qqq == sMAC 是 true。此外，通过binascii 打印的两个变量都显示出相似的值。变量qqq 来自bytearray.fromhex('7A414086D86A4BF5554AE6FBC4AC0465')，变量sMAC 来自"7A414086D86A4BF5554AE6FBC4AC0465",decode('hex')。

>>> qqq[0]
122
>>> sMAC[0]
'z'
>>> qqq == sMAC
True
>>> binascii.hexlify(sMAC)
'7a414086d86a4bf5554ae6fbc4ac0465'
>>> binascii.hexlify(qqq)
'7a414086d86a4bf5554ae6fbc4ac0465'
>>> qqq == sMAC
True
>>> repr(qqq)
"bytearray(b'zA@\\x86\\xd8jK\\xf5UJ\\xe6\\xfb\\xc4\\xac\\x04e')"
>>> repr(sMAC)
"'zA@\\x86\\xd8jK\\xf5UJ\\xe6\\xfb\\xc4\\xac\\x04e'"
>>> cipher1 = triple_des(qqq,CBC,"\0\0\0\0\0\0\0\0",pad=None,padmode=PAD_PKCS5)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/john/.local/lib/python2.7/site-packages/pyDes.py", line 710, in __init__
    self.setKey(key)
  File "/home/john/.local/lib/python2.7/site-packages/pyDes.py", line 727, in setKey
    self._padding, self._padmode)
  File "/home/john/.local/lib/python2.7/site-packages/pyDes.py", line 409, in __init__
    self.setKey(key)
  File "/home/john/.local/lib/python2.7/site-packages/pyDes.py", line 414, in setKey
    self.__create_sub_keys()
  File "/home/john/.local/lib/python2.7/site-packages/pyDes.py", line 462, in __create_sub_keys
    key = self.__permutate(des.__pc1, self.__String_to_BitList(self.getKey()))
  File "/home/john/.local/lib/python2.7/site-packages/pyDes.py", line 421, in __String_to_BitList
    data = [ord(c) for c in data]
TypeError: ord() expected string of length 1, but int found
>>> cipher1 = triple_des(sMAC,CBC,"\0\0\0\0\0\0\0\0",pad=None,padmode=PAD_PKCS5)
>>>

希望这个额外的细节有所帮助。