解决Python3.6，发送POST请求错误提示：POST data should be bytes, an iterable of bytes, or a file object. It canno

之前遇到的坑，今天又遇到了，在此记录一下，

爬虫时，转码data时，出现下面错误信息：

POST data should be bytes, an iterable of bytes, or a file object. It cannot be of type str.

测试代码：

# -*- coding:utf-8 -*-

import urllib.request

def movieSpider():
"""
模拟Ajax请求

"""

url = "https://movie.douban.com/j/chart/top_list?"

header = {"User-Agent" : "Opera/9.80 (Windows NT 6.1; U; en) Presto/2.7.62 Version/11.01"}

formData = {
"type" : "11",
"interval_id" : "100:90",
"action" : "",
"start" : "0",
"limit" : "20"
}

data = urllib.parse.urlencode(formData)

request = urllib.request.Request(url, data=data, headers=header)

print(url)
print(data)

print(urllib.request.urlopen(request).read())

if __name__ == "__main__":
movieSpider()

报错截图：



查看源文档：https://docs.python.org/3/library/urllib.parse.html

Convert a mapping object or a sequence of two-element tuples, which may contain str or bytes objects, to a percent-encoded ASCII text string. If the resultant string is to be used as a data for POST operation with the urlopen() function, then it should be encoded to bytes, otherwise it would result in a TypeError.

简洁明了一句话，转码为bytes类型

修改代码如下：

# -*- coding:utf-8 -*-

import urllib.request

def movieSpider():
"""
模拟Ajax请求

"""

url = "https://movie.douban.com/j/chart/top_list?"

header = {"User-Agent" : "Opera/9.80 (Windows NT 6.1; U; en) Presto/2.7.62 Version/11.01"}

formData = {
"type" : "11",
"interval_id" : "100:90",
"action" : "",
"start" : "0",
"limit" : "20"
}

#将str类型转换为bytes类型
data = urllib.parse.urlencode(formData).encode("utf-8")

request = urllib.request.Request(url, data=data, headers=header)

print(urllib.request.urlopen(request).read().decode("utf-8"))

if __name__ == "__main__":
movieSpider()


测试结果(部分截图)：



总结：

多看源文档少踩坑