day-1 用python编写一个简易的FTP服务器

　　从某宝上购买了一份《Python神经网络深度学习》课程，按照视频教程，用python语言，写了一个简易的FTP服务端和客户端程序，以前也用C++写过聊天程序，编程思路差不多，但是python编程时更顺畅，代码量更少。没有很高深的理论知识，也不需要扎实的编程基础，知道需要用哪些库就行了。

　　两种语言对比，初次感受到python语言的易用之处，python的核心是简洁清晰，也是伪代码的最佳实践语言。可以理解为C语言的一些常用功能库的转义，所以普遍认为python语言带来编程便捷的同时，也会带来一部分性能的牺牲。但这并不也是绝对的，有时候程序的开发效率更为重要，更何况并不一定人人都是大牛，用C或者其它语言未必就能写出比python更高性能的代码。整体学习完以后，还会再来深入对比下python和其他语言的差异。

１、基本功能

　　登陆验证

　　上传：支持断点上传，MD５验证

　　简单命令：cd、ls、mkdir

2、常用模块

　　下面是我汇总的用到的模块信息，要写出完整的代码，首先得了解基本的python函数和库，例如：

　　os，sys库对目录和文件的处理；

　　socket和socketserver对网络通信的处理；

　　json对传输数据格式的处理；

　　configparse对配置文件的处理；

　　hashlib对MD5校验的处理；

　　optparse对命令行输入参数的格式化处理等；

　　另外还需要了解如何利用反射机制，处理多If else分支的函数调用等。

　　关于python反射机制，参考链接：https://www.cnblogs.com/Guido-admirers/p/6206212.html

3、具体代码

　　

　　ftp_client.py：FTP客户端主程序

import socket
import optparse
import json
import os,sys
import hashlib

STATUS_CODE  = {
    250 : "Invalid cmd format, e.g: {'action':'get','filename':'test.py','size':344}",
    251 : "Invalid cmd ",
    252 : "Invalid auth data",
    253 : "Wrong username or password",
    254 : "Passed authentication",
    255 : "Filename doesn't provided",
    256 : "File doesn't exist on server",
    257 : "ready to send file",
    258 : "md5 verification",
    800 : "the file exist,but not enough ,is continue? ",
    801 : "the file exist !",
    802 : " ready to receive datas",
    900 : "md5 valdate success"
}

sk = socket.socket()
sk.connect(("127.0.0.1",18000))

class ClientHander():
    def __init__(self):

        #初始化变量
        self.op = optparse.OptionParser()
        self.op.add_option("-s","--server",dest="server")
        self.op.add_option("-P", "--port", dest="port")
        self.op.add_option("-u", "--username", dest="username")
        self.op.add_option("-p", "--password", dest="password")
        self.options,self.args = self.op.parse_args()
        #self.verify_args(self.options,self.args)
        self.mainPath = os.path.dirname(os.path.abspath(__file__))
        self.last = 0
        self.is_authenticated = False
        self.is_connected = False
        self.is_needed_md5 = True

        #开始建立连接
        self.make_connection()

    # 验证用户输入信息
    def verify_args(self,options,args):
        server = options.server
        port = options.port
        username = options.username
        password = options.password
        if int(port) > 0 and int(port) < 65535:
            return True
        else:
            exit("the port should been in 0-65535")

    # 连接服务器
    def make_connection(self):
        if not self.is_connected:
            self.sock = socket.socket()
            self.sock.connect(("127.0.0.1", 18000))
            self.is_connected = True
        return

    def interactive(self):

        # 判断是否已经验证过
        if not self.is_authenticated:
            self.make_connection()
            self.authenticate()

        # 开始和服务器进行交互
        cmd_info = input("[%s]"%self.current_dir).strip()
        # 利用反射机制，建立命令与功能对应关系
        cmd_list = cmd_info.split()
        if hasattr(self,cmd_list[0]):
            func = getattr(self,cmd_list[0])
            func(*cmd_list)

    def authenticate(self):
        if not self.is_connected:
            print("没有连接FTP服务器")
            return
        if self.options.username is None or self.options.password is None:
            username = input("username:")
            password = input("password:")
            return self.get_auth_result(username,password)
        return self.get_auth_result(self.options.username,self.options.password)

    def response(self):
        data = self.sock.recv(1024).decode("utf-8")
        data = json.loads(data)
        return data

    def get_auth_result(self,username,password):
        data = {
            "action":"auth",
            "username":username,
            "password":password
        }
        self.sock.send(json.dumps(data).encode("utf-8"))
        res = self.response()
        print("res",res["status_code"])
        if res["status_code"] ==  254:
            self.username = username
            self.current_dir = username
            self.is_authenticated = True
            print(STATUS_CODE[254])
            return True
        else:
            print(STATUS_CODE[res["status_code"]])

    def put(self,*cmd_list):

        # 1 发送上传命令
        action,local_path,target_path = cmd_list
        local_path = os.path.join(self.mainPath,local_path)
        file_name = os.path.basename(local_path)
        file_size = os.stat(local_path).st_size
        data = {
            "action":"put",
            "file_name": file_name,
            "file_size": file_size,
            "target_path": target_path
        }
        self.sock.sendall(json.dumps(data).encode("utf-8"))

        # 2 接收服务器检查结果
        has_sent = 0
        is_exsit = self.sock.recv(1024).decode("utf-8")

        # 3 根据服务器检查结果，执行相应命令
        # 文件存在但不完整
        if is_exsit == "":
            print("服务器文件已经存在，且不完整")
            # 和服务器确认是否继续上传
            choice = input("The file exist but not enough,is continue?[Y/N]").strip()
            # 继续上传
            if choice.upper() == "Y":
                self.sock.sendall("Y".encode("utf-8"))
                # 等待服务器返回存在文件大小
                continue_position = self.sock.recv(1024).decode("utf-8")
                has_sent += int(continue_position)
            # 不继续上传
            else:
                self.sock.sendall("N".encode("utf-8"))
        # 文件存在且完整
        elif is_exsit == "":
            print("服务器文件已经存在，且完整")
            return
        f = open(local_path,"rb")
        f.seek(has_sent)

        md5_obj = None
        if self.is_needed_md5:
            md5_obj = hashlib.md5()

        while has_sent < file_size:
            data = f.read(1024)
            self.sock.sendall(data)
            if md5_obj:
                md5_obj.update(data)
            has_sent += len(data)

        mdt_val_server = self.sock.recv(1024).decode("utf-8")
        mdt_val_client = md5_obj.hexdigest()
        self.show_progress(has_sent,file_size)
        print("client's md5 is %s"%mdt_val_client)
        print("server's md5 is %s" %mdt_val_server)
        f.close()

        if mdt_val_client == mdt_val_server:
            print("put success")
        else:
            print("Athenticate MD5 failed.")

    def show_progress(self,has,total):
        rate = float(has) / float(total)
        rate_num = int(rate*100)
        print("%s%% %s\r"%(rate_num,"#"*rate_num))

    def ls(self,*cmd_list):
        data = {
            "action":"ls"
        }
        self.sock.sendall(json.dumps(data).encode("utf-8"))
        data = self.sock.recv(1024).decode("utf-8")
        print(data)

    def cd(self,*cmd_list):
        # cd images
        data = {
            "action":"cd",
            "dirname":cmd_list[1]
        }
        self.sock.sendall(json.dumps(data).encode("utf-8"))
        data = self.sock.recv(1024).decode("utf-8")
        self.current_dir = os.path.basename(data)
        print(os.path.basename(data))

    def mkdir(self,*cmd_list):
        data = {
            "action":"mkdir",
            "dirname":cmd_list[1]
        }

        self.sock.sendall(json.dumps(data).encode("utf-8"))
        data = self.sock.recv(1024).decode("utf-8")
        print(data)

ch = ClientHander()
while 1:
    ch.interactive()

　　ftp_server.py：FTP服务器端主程序

import os,sys

PATH = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
sys.path.append(PATH)

from core import main

if __name__ == '__main__':
    main.ArgvHandler()

　　main.py：处理参数输入

import optparse
import socketserver
from conf import settings
from core import server

class ArgvHandler():

    def __init__(self):
        self.op = optparse.OptionParser()
        #self.op.add_option("-s","--server",dest = "server")
        #self.op.addd_option("-P", "--port", dest="port")

        options,args = self.op.parse_args()
        self.verify_args(options,args)

    def verify_args(self,options,args):
        #首先判断参数的长度
        if len(args) < 1:
            print("参数个数太少，请重新输入.")
        else:
            cmd = args[0]
            if hasattr(self,cmd):
                func = getattr(self,cmd)
                func()
        self.start()

    def start(self):
        s = socketserver.ThreadingTCPServer((settings.IP,settings.PORT),server.ServerHandler)
        print("服务器已经启动")
        s.serve_forever()

    def help(self):
        pass

　　server.py：具体代码实现

import socketserver
import json
import configparser
from conf import settings
import os
import hashlib

STATUS_CODE  = {

    250 : "Invalid cmd format, e.g: {'action':'get','filename':'test.py','size':344}",
    251 : "Invalid cmd ",
    252 : "Invalid auth data",
    253 : "Wrong username or password",
    254 : "Passed authentication",
    255 : "Filename doesn't provided",
    256 : "File doesn't exist on server",
    257 : "ready to send file",
    258 : "md5 verification",

    800 : "the file exist,but not enough ,is continue? ",
    801 : "the file exist !",
    802 : " ready to receive datas",

    900 : "md5 valdate success"

}

class ServerHandler(socketserver.BaseRequestHandler):
    def handle(self):
        while 1:
            data = self.request.recv(1024).strip()
            if not data:continue
            data = json.loads(data.decode("utf-8"))

            if data.get("action"):
                if hasattr(self,data.get("action")):
                    func = getattr(self,data.get("action"))
                    func(**data)
                else:
                    print("Invalid cmd")
            else:
                print("Invalid cmd")

    def send_response(self,status_code):
        response = {"status_code":status_code}
        self.request.sendall(json.dumps(response).encode("utf8"))

    def auth(self,**data):
        username = data["username"]
        password = data["password"]
        print("收到客户端验证请求，用户名：",username,"密码：",password)
        user = self.authenticate(username,password)
        if user:
            self.send_response(254)
        else:
            self.send_response(253)

    def authenticate(self,username,password):
        cfg = configparser.ConfigParser()
        cfg.read(settings.ACCOUNT_PATH)
        print("正在读取配置用户配置信息：",settings.ACCOUNT_PATH)

        if username in cfg.sections():
            if cfg[username]["Password"] == password:
                self.useranme = username
                self.mainPath = os.path.join(settings.BASE_DIR,"home",self.useranme)
                print("成功匹配上用户信息,用户密码:", cfg[username]["Password"])
                print("用户根目录为:",self.mainPath)
                return username

    def put(self,**data):
        print("data",data)
        file_name = data.get("file_name")
        file_size = data.get("file_size")
        target_path = data.get("target_path")

        abs_path = os.path.join(self.mainPath,target_path,file_name)

        has_received = 0

        if os.path.exists(abs_path):
            file_has_size = os.stat(abs_path).st_size
            if file_has_size < file_size:
                #断点续传
                self.request.sendall("".encode("utf-8"))
                choice = self.request.recv(1024).decode("utf-8")
                if choice.upper() == "Y":
                    self.request.sendall(str(file_has_size).encode("utf-8"))
                    f = open(abs_path,"ab")
                    has_received += file_has_size
                else:
                    f = open(abs_path,"wb")
            else:
                #文件完全存在
                self.request.sendall("".encode("utf-8"))
                return
        else:
            self.request.sendall("".encode("utf-8"))
            f = open(abs_path, "wb")

        md5_obj = hashlib.md5()

        while has_received < file_size:
            try:
                data = self.request.recv(1024)
                f.write(data)
                md5_obj.update(data)
                has_received += len(data)
            except Exception as e:
                print("传输文件发生异常：",str(e))
                break

        # 给客户端发送MD5
        md5_val = md5_obj.hexdigest()
        self.request.sendall(md5_val.encode("utf-8"))

        f.close()

    def ls(self,**data):
        file_list = os.listdir(self.mainPath)
        print("ls %s"%self.mainPath)
        if not file_list:
            file_str = "<empty dir>"
        else:
            file_str = "\n".join(file_list)
        self.request.sendall(file_str.encode("utf-8"))

    def cd(self,**data):
        dir_name = data.get("dirname")
        print("cd %s\n"%dir_name)
        if dir_name == "..":
            self.mainPath = os.path.dirname(self.mainPath)
        else:
            self.mainPath = os.path.join(self.mainPath,dir_name)

        self.request.sendall(self.mainPath.encode("utf-8"))

    def mkdir(self,**data):
        dirname = data.get("dirname")
        path = os.path.join(self.mainPath,dirname)
        if not os.path.exists(path):
            if "/" in dirname:
                os.makedirs(path)
            else:
                os.mkdir(path)
            self.request.sendall("create success".encode("utf-8"))
        else:
            self.request.sendall("dirname exist".encode("utf-8"))

　　accounts.cfg：账户信息，登陆验证用

[DEFAULT]
[tanbiao]
Password = tanbiao
Quotation = 100

[root]
Password = root
Quotation = 100

　　setting.py：配置信息

import os

BASE_DIR=os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

IP="127.0.0.1"
PORT=18000

ACCOUNT_PATH=os.path.join(BASE_DIR,"conf","accounts.cfg")