1.基本需求
编写登陆接口，实现如下需求：
（1）输入用户名密码
（2）认证成功后显示欢迎信息
（3）输错三次后锁定
2.实现细节
·每添加一个用户，需要手动添加三个文件
| 文件 | 功能 |
| username_count.txt | 记录用户输错密码的次数，最大为3次，如果用户密码输入正确，则重置为0，默认为0 |
| username_lock.txt | 记录用户是否被锁定，1表示锁定，0表示未锁定，默认为0 |
| username_passwd.txt | 记录用户的密码 |
·注：username是指该用户的用户名，视具体的用户名而定；
·每添加一个用户，在username.txt中写入该用户名，一个用户名占一行（手动）；
·如果输入的用户名或密码为空，都要求重新输入；
·输入不存在的用户名，只会提示“username or password wrong”；
·输入存在的用户名，才会进行密码输入错误次数的记录。
3.实现代码与注释
import sys,os count = 0 #To count, if the user is locked. mark_user = 0 #To make sure if the user is existing. mark_passwd = 0 #To make sure if the password is right. while count < 3: name = raw_input(‘Username:‘).strip() if len(name) == 0: print ‘The username can not be empty!‘ continue key = raw_input(‘Password:‘).strip() if len(key) == 0: print ‘The password can not be empty!Try again!‘ continue #Upon:To check if the username or password is empty.检查用户名或密码是否为空 f = file(‘username.txt‘, ‘r‘) userlist = f.readlines() f.close() for user in userlist: if user.strip() == name: mark_user = 1 #检查输入的用户是否在username.txt文件中，即是否注册，如果在，mark_user = 1 if mark_user == 1: f = file(‘%s_lock.txt‘ % (name), ‘r‘) locked = int(f.readline().strip()) f.close() else: print ‘Username or password wrong!‘ break #Upon:To check if exist,if not exist,printing username or password wrong!And quit the program. #用户名不存在就提示用户名或密码错误，用户名存在就检查该用户是否被锁定 if locked == 1: sys.exit(‘Sorry, the username had been locked!!!Please call the system administrator.‘) #Upon:To check if the username is locked by the system. else: f = file(‘%s_passwd.txt‘ % (name), ‘r‘) passwd = (f.readline().strip()) if passwd.strip() == key: mark_passwd = 1 # check the password from the name_input password file. if mark_user == 1 and mark_passwd == 1: f = file(‘%s_count.txt‘ % name, ‘w‘) f.write(‘0‘) f.close() sys.exit(‘%s, welcome to our system!‘ % name) #用户名和密码正确，将username_count.txt内容重置为0 else: f = file(‘%s_count.txt‘ % name, ‘r‘) count = int((f.read().strip())) f.close() count += 1 f = file(‘%s_count.txt‘ % name, ‘w‘) f.write(str(count)) f.close() #open the count file of the user and change it. #密码不正确，就把count次数记录在该用户名对应的文件count文件上 print ‘‘‘Username or password wrong! And the username ‘%s‘ has %d more chances to retry!‘‘‘ % (name, 3 - count) if count == 3: print "‘%s‘ has been locked!!!" % (name) if os.path.exists(‘%s_lock.txt‘ % (name)): fobj = open(‘%s_lock.txt‘ % (name), ‘w‘) fobj.writelines(‘1\n‘) else: print ‘Username or password wrong!‘ continue #Upon:To check if the username and password are right, if not, the count will add 1. #如果count次数为3，则将用户对应的lock文件内容重置为1，锁定该用户
4.测试
--对单一用户xpleaf的测试
·在对应4个文件中添加相应信息：
xpleaf@xpleaf-machine:~/seminar6/day1$ head username.txt xpleaf_count.txt xpleaf_lock.txt xpleaf_passwd.txt ==> username.txt <== xpleaf ==> xpleaf_count.txt <== 0 ==> xpleaf_lock.txt <== 0 ==> xpleaf_passwd.txt <== xpleaf123
·正常输入用户名和密码：
xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:xpleaf Password:xpleaf123 xpleaf, welcome to our system!
·故意输错两次密码后查看相关文件：
xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:xpleaf Password:klkdf Username or password wrong! And the username ‘xpleaf‘ has 2 more chances to retry! Username:xpleaf Password:kldf Username or password wrong! And the username ‘xpleaf‘ has 1 more chances to retry! Username:Traceback (most recent call last): File "newlogin.py", line 8, in <module> name = raw_input(‘Username:‘).strip() EOFError xpleaf@xpleaf-machine:~/seminar6/day1$ cat xpleaf_count.txt 2
·可以看到count文件已经记录为2，再输入正确的用户名和密码：
xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:xpleaf Password:xpleaf123 xpleaf, welcome to our system! xpleaf@xpleaf-machine:~/seminar6/day1$ cat xpleaf_count.txt 0
·count文件重置为0；
·连续输入密码错误超过3次：
0xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:xpleaf Password:kldf Username or password wrong! And the username ‘xpleaf‘ has 2 more chances to retry! Username:xpleaf Password:klkdf Username or password wrong! And the username ‘xpleaf‘ has 1 more chances to retry! Username:xpleaf Password:kldf Username or password wrong! And the username ‘xpleaf‘ has 0 more chances to retry! ‘xpleaf‘ has been locked!!! xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:xpleaf Password:xpleaf123 Sorry, the username had been locked!!!Please call the system administrator. xpleaf@xpleaf-machine:~/seminar6/day1$ cat xpleaf_lock.txt 1
·用户已经被锁定，对应lock文件内容变为1，如果需要解锁，则要手动将该文件重置为0；
·输入错误的用户名：
xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:klkdlf Password:klkdf Username or password wrong!
·只会提示用户名或密码错误，不会做相关文件记录；
--对两个用户xpleaf和yonghaoyip的测试
·为用户yonghaoyip添加相关文件信息：
xpleaf@xpleaf-machine:~/seminar6/day1$ head username.txt yonghaoyip_count.txt yonghaoyip_lock.txt yonghaoyip_passwd.txt ==> username.txt <== xpleaf yonghaoyip ==> yonghaoyip_count.txt <== 0 ==> yonghaoyip_lock.txt <== 0 ==> yonghaoyip_passwd.txt <== yonghaoyip123
·主要测试两个用户的count文件记录：
对用户yonghaoyip操作： xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:yonghaoyip Password:klkdf Username or password wrong! And the username ‘yonghaoyip‘ has 2 more chances to retry! Username:yonghaoyip Password:kldf Username or password wrong! And the username ‘yonghaoyip‘ has 1 more chances to retry! Username:Traceback (most recent call last): File "newlogin.py", line 8, in <module> name = raw_input(‘Username:‘).strip() EOFError 对用户xpleaf操作： xpleaf@xpleaf-machine:~/seminar6/day1$ python newlogin.py Username:xpleaf Password:kkjlkdf Username or password wrong! And the username ‘xpleaf‘ has 2 more chances to retry! Username:xpleaf Password:xpleaf123 xpleaf, welcome to our system! 查看两个用户对应的count文件记录： xpleaf@xpleaf-machine:~/seminar6/day1$ head yonghaoyip_count.txt xpleaf_count.txt ==> yonghaoyip_count.txt <== 2 ==> xpleaf_count.txt <== 0
·可以看到两个用户的相关文件并不会相互影响。
本文出自 “香飘叶子” 博客，请务必保留此出处http://xpleaf.blog.51cto.com/9315560/1691400
原文地址：http://xpleaf.blog.51cto.com/9315560/1691400
