今天是又一年度的2月14日西方情人节，先说点与情人节有关的，但这绝不是狗粮，可以放心阅读。
讲真，如果你是单身狗，没事时还是要静下心学习以提升自己；如果你不是单身狗，没事时除了上一条还要多陪陪媳妇和家人。因为没有什么是比亲人和提升自己更重要的事了！无论是提升自己还是陪伴家人，不要浮于表面，就像今天过情人节一样，向对方表达爱并不是只有这一天和那几天，而是男女双方长久的坚持和包容。
用以前有人用过的句子说：
当你的才华撑不起你的野心，那你就应该静下心来学习；当你的金钱赶不上你的梦想，那你就应该坐下来好好工作；当你的能力还驾驭不了你的目标，那就应该沉下心来历练！
正文开始：
本文为使用python脚本检验文件系统数据完整性和防止数据篡改提供一种简单且容易实现的思路（其实很简单，只需要了解Python基础+hashlib+文件操作等）。
虽然校验数据完整性这个话题已经由很多更加完美的解决办法，但依然可以作为Python新手练手内容之一，培养一下逻辑思维，防止“老年痴呆”。
目前已经在windows 10以及Ubuntu（Python 2.7）下测试通过，其他的平台应该也可以，欢迎帮忙测试。
编写的思路和执行过程简要如下：
1.输入要检查数据完整性的目录的路径（也支持单个文件）和要保存文件hash值的校验文件的路径，如果路径不存在，则抛出异常或者创建，取决于具体情况；
参数传入（关于参数传入部分的未改进说明见文末的TODO部分）：
合法的参数和路径：
路径不存在时抛出异常：
其他异常处理可以通过脚本内容看到。
2.首次执行保存需要校验hash值的校验文件的内容，再次执行读取原先的文件与现在的待校验的目录中的文件的hash值做比对，如果hash值不一样，则显示出该文件路径，如果全部一致，则输出提示信息
首次执行：
再次执行（检验通过）：
校验不通过：
3.当文件发生变更并且想更新校验文件数据时，可以使用remakeDataIntegrity()函数将已保存的校验文件删除
linux上的测试：
代码如下：
#!/usr/bin/python # encoding: utf-8 # -*- coding: utf8 -*- """ Created by PyCharm. File: LinuxBashShellScriptForOps:checkDataIntegrity.py User: Guodong Create Date: 2017/2/14 Create Time: 14:45 """ import os import sys import hashlib # TODO(Guodong Ding) using 'docopt' to accept parameters and command switch, import docopt # TODO(Guodong Ding) define a help doc in function here def get_hash_sum(filename, method="sha256", block_size=65536): if not os.path.exists(filename): raise RuntimeError("cannot open '%s' (No such file or directory)" % filename) if not os.path.isfile(filename): raise RuntimeError("'%s' :not a regular file" % filename) if "md5" in method: checksum = hashlib.md5() elif "sha1" in method: checksum = hashlib.sha1() elif "sha256" in method: checksum = hashlib.sha256() elif "sha384" in method: checksum = hashlib.sha384() elif "sha512" in method: checksum = hashlib.sha512() else: raise RuntimeError("unsupported method %s" % method) with open(filename, 'rb') as f: buf = f.read(block_size) while len(buf) > 0: checksum.update(buf) buf = f.read(block_size) if checksum is not None: return checksum.hexdigest() else: return checksum def makeDataIntegrity(path): path = unicode(path, 'utf8') # For Chinese Non-ASCII character if not os.path.exists(path): raise RuntimeError("Error: cannot access %s: No such file or directory" % path) elif os.path.isfile(path): dict_all = dict() dict_all[os.path.abspath(path)] = get_hash_sum(path) return dict_all elif os.path.isdir(path): dict_nondirs = dict() dict_dirs = dict() for top, dirs, nondirs in os.walk(path, followlinks=True): for item in nondirs: # Do NOT use os.path.abspath(item) here, else it will make a serious bug because of # os.path.abspath(item) return "os.getcwd()" + "filename" in some case. dict_nondirs[os.path.join(top, item)] = get_hash_sum(os.path.join(top, item)) for item in dirs: dict_dirs[os.path.join(top, item)] = r"" dict_all = dict(dict_dirs, **dict_nondirs) return dict_all def saveDataIntegrity(data, filename): import json data_to_save = json.dumps(data, encoding='utf-8') if not os.path.exists(os.path.dirname(filename)): os.makedirs(os.path.dirname(filename)) with open(filename, 'wb') as f: f.write(data_to_save) def readDataIntegrity(filename): import json if not os.path.exists(filename): raise RuntimeError("cannot open '%s' (No such file or directory)" % filename) with open(filename, 'rb') as f: data = json.loads(f.read()) if data: return data def remakeDataIntegrity(filename): def confirm(question, default=True): """ Ask user a yes/no question and return their response as True or False. :parameter question: ``question`` should be a simple, grammatically complete question such as "Do you wish to continue?", and will have a string similar to " [Y/n] " appended automatically. This function will *not* append a question mark for you. The prompt string, if given,is printed without a trailing newline before reading. :parameter default: By default, when the user presses Enter without typing anything, "yes" is assumed. This can be changed by specifying ``default=False``. :return True or False """ # Set up suffix if default: # suffix = "Y/n, default=True" suffix = "Y/n" else: # suffix = "y/N, default=False" suffix = "y/N" # Loop till we get something we like while True: response = raw_input("%s [%s] " % (question, suffix)).lower() # Default if not response: return default # Yes if response in ['y', 'yes']: return True # No if response in ['n', 'no']: return False # Didn't get empty, yes or no, so complain and loop print("I didn't understand you. Please specify '(y)es' or '(n)o'.") if os.path.exists(filename): if confirm("[warning] remake data integrity file \'%s\'?" % filename): os.remove(filename) print "[successful] data integrity file \'%s\' has been remade." % filename sys.exit(0) else: print "[warning] data integrity file \'%s\'is not remade." % filename sys.exit(0) def checkDataIntegrity(path_to_check, file_to_save): from time import sleep if not os.path.exists(file_to_save): print "[info] Do make a data integrity file to %s" % file_to_save data = makeDataIntegrity(path_to_check) saveDataIntegrity(data, file_to_save) print "[successful] Do make a data integrity file to %s, finished!" % file_to_save, print "Now you can use this script later to check data integrity." else: old_data = readDataIntegrity(file_to_save) new_data = makeDataIntegrity(path_to_check) error_flag = True for item in old_data.keys(): if not old_data[item] == new_data[item]: print>> sys.stderr, new_data[item], item sleep(0.01) print "\told hash data is %s" % old_data[item], item error_flag = False if error_flag: print "[ successful ] passed, All files integrity is ok!" if __name__ == '__main__': # remakeDataIntegrity("/tmp/data_integrity_1.json") checkDataIntegrity(r"E:\Users\Guodong\PycharmProjects\LinuxBashShellScriptForOps\functions\security", "/tmp/data_integrity_1.json")已知需要改进的地方：
1.编写一个帮助函数，在异常或者需要帮助的时候打印帮助内容
2.添加参数和命令开关支持，使脚本可以接收参数和命令开关，使用起来更加灵活。
由于时间关系暂时不写了，等有时间再做添加，可以关注GitHub获取最新版本。
tag:Python校验文件完整性,文件完整性,哈希校验
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