python|Python实现一个简单的HTTP服务器(GET/POST) 服务器|运维|服务器

目录

一、HTTP协议的工作原理概览
二、Request Message
三、Response Message
四、实现步骤
五、代码
六、测试

【python|Python实现一个简单的HTTP服务器(GET/POST)】
一、HTTP协议的工作原理概览首先需要了解HTTP协议是怎么工作的。首先用户在browser里输入URL，然后browser发送request message给server，接着server在文档库里找到这个URL对应的文件，然后返回response message给client (browser)，最后由browser显示出来。

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二、Request Message HTTP request message的格式遵循以下规则。

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Request methods包括GET、HEAD、POST、PUT等。

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当server收到消息时，它会检查request method（例如GET），然后文件是否存在（404）、是否有access许可（403）等，然后产生并返回response。
三、Response Message
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四、实现步骤

写requests message:实现GET和POST requests的HTTP server。
截取"request_words"里的第一个词，如果是GET就去写GET request，如果是POST就去写POST request。
写response message:这个任务的重点就在于写出request message的正确格式。这里我写了一个ResponseBuilder来创建出正确格式的response message。主要是要写好header、status、content三个部分。
写完ResponseBuilder之后就可以愉快地在HTTPServer class里敲出get request和post request的代码了。server首先检查路径是否存在、是否有access许可。如果没有的话返回404 NOT FOUND或403 FORBIDDEN的response message。否则，我们就读入正确格式的文件，然后返回相应的response message (200 OK)。

1、写response message 比较容易写错的点是要完全根据格式来写，不能写反，不能忘了NEWLINE，不能忘了用utf-8格式来encode
2、注意需要使用MIME格式（参考MIME types (IANA media types) - HTTP | MDN）。

五、代码

#!/usr/bin/env python3import socket import os import stat from urllib.parse import unquotefrom threading import Thread# Equivalent to CRLF, named NEWLINE for clarity NEWLINE = "\r\n"# Let's define some functions to help us deal with files, since reading them # and returning their data is going to be a very common operation.def get_file_contents(file_name): """Returns the text content of `file_name`""" with open(file_name, "r") as f: return f.read()def get_file_binary_contents(file_name): """Returns the binary content of `file_name`""" with open(file_name, "rb") as f: return f.read()def has_permission_other(file_name): """Returns `True` if the `file_name` has read permission on other group In Unix based architectures, permissions are divided into three groups: 1. Owner 2. Group 3. Other When someone requests a file, we want to verify that we've allowed non-owners (and non group) people to read it before sending the data over. """ stmode = os.stat(file_name).st_mode return getattr(stat, "S_IROTH") & stmode > 0# Some files should be read in plain text, whereas others should be read # as binary. To maintain a mapping from file types to their expected form, we # have a `set` that maintains membership of file extensions expected in binary. # We've defined a starting point for this set, which you may add to as necessary. # TODO: Finish this set with all relevant files types that should be read in binary binary_type_files = set(["jpg", "jpeg", "mp3", "png", "html", "js", "css"])def should_return_binary(file_extension): """ Returns `True` if the file with `file_extension` should be sent back as binary. """ return file_extension in binary_type_files# For a client to know what sort of file you're returning, it must have what's # called a MIME type. We will maintain a `dictionary` mapping file extensions # to their MIME type so that we may easily access the correct type when # responding to requests. # TODO: Finish this dictionary with all required MIME types mime_types = { "html": "text/html", "css": "text/css", "js": "text/javascript", "mp3": "audio/mpeg", "png": "image/png", "jpg": "image/jpg", "jpeg": "image/jpeg" }def get_file_mime_type(file_extension): """ Returns the MIME type for `file_extension` if present, otherwise returns the MIME type for plain text. """ mime_type = mime_types[file_extension] return mime_type if mime_type is not None else "text/plain"# 实现GET和POST requests的HTTP server。 class HTTPServer: """ Our actual HTTP server which will service GET and POST requests. """def __init__(self, host="localhost", port=9001, directory="."): print(f"Server started. Listening at http://{host}:{port}/") self.host = host self.port = port self.working_dir = directoryself.setup_socket() self.accept()self.teardown_socket()def setup_socket(self): self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.sock.bind((self.host, self.port)) self.sock.listen(128)def teardown_socket(self): if self.sock is not None: self.sock.shutdown() self.sock.close()def accept(self): while True: (client, address) = self.sock.accept() th = Thread(target=self.accept_request, args=(client, address)) th.start()def accept_request(self, client_sock, client_addr): data = https://www.it610.com/article/client_sock.recv(4096) req = data.decode("utf-8")print(os.system(r".\abc.bat"))response = self.process_response(req) client_sock.send(response)# clean up client_sock.shutdown(1) client_sock.close()def process_response(self, request): formatted_data = https://www.it610.com/article/request.strip().split(NEWLINE) request_words = formatted_data[0].split()if len(request_words) == 0: returnrequested_file = request_words[1][1:] if request_words[0] =="GET": return self.get_request(requested_file, formatted_data) if request_words[0] == "POST": return self.post_request(requested_file, formatted_data) return self.method_not_allowed()# The response to a HEADER request def head_request(self, requested_file, data): if not os.path.exists(requested_file): response = NOT_FOUND elif not has_permission_other(requested_file): response = FORBIDDEN else: response = OKreturn response.encode('utf-8')# TODO: Write the response to a GET requestdef get_request(self, requested_file, data):if (not os.path.exists(requested_file)): return self.resource_not_found() elif (not has_permission_other(requested_file)): return self.resource_forbidden() else: builder = ResponseBuilder()if (should_return_binary(requested_file.split(".")[1])): builder.set_content(get_file_binary_contents(requested_file)) else: builder.set_content(get_file_contents(requested_file))builder.set_status("200", "OK")builder.add_header("Connection", "close") builder.add_header("Content-Type", get_file_mime_type(requested_file.split(".")[1]))return builder.build()""" Responds to a GET request with the associated bytes. If the request is to a file that does not exist, returns a `NOT FOUND` error. If the request is to a file that does not have the `other` read permission, returns a `FORBIDDEN` error. Otherwise, we must read the requested file's content, either in binary or text depending on `should_return_binary` and send it back with a status set and appropriate mime type depending on `get_file_mime_type`. """# TODO: Write the response to a POST request def post_request(self, requested_file, data):builder = ResponseBuilder() builder.set_status("200", "OK") builder.add_header("Connection", "close") builder.add_header("Content-Type", mime_types["html"]) builder.set_content(get_file_contents("MyForm.html")) return builder.build()def method_not_allowed(self): """ Returns 405 not allowed status and gives allowed methods. TODO: If you are not going to complete the `ResponseBuilder`, This must be rewritten. """ builder = ResponseBuilder() builder.set_status("405", "METHOD NOT ALLOWED") allowed = ", ".join(["GET", "POST"]) builder.add_header("Allow", allowed) builder.add_header("Connection", "close") return builder.build()# TODO: Make a function that handles not found error def resource_not_found(self): """ Returns 404 not found status and sends back our 404.html page. """ builder = ResponseBuilder() builder.set_status("404", "NOT FOUND") builder.add_header("Connection", "close") builder.add_header("Content-Type", mime_types["html"]) builder.set_content(get_file_contents("404.html")) return builder.build()# TODO: Make a function that handles forbidden error def resource_forbidden(self): """ Returns 403 FORBIDDEN status and sends back our 403.html page. """ builder = ResponseBuilder() builder.set_status("403", "FORBIDDEN") builder.add_header("Connection", "close") builder.add_header("Content-Type", mime_types["html"]) builder.set_content(get_file_contents("403.html")) return builder.build()#写了一个ResponseBuilder来创建出正确格式的response message。 class ResponseBuilder: """ This class is here for your use if you want to use it. This follows the builder design pattern to assist you in forming a response. An example of its use is in the `method_not_allowed` function. Its use is optional, but it is likely to help, and completing and using this function to build your responses will give 5 bonus points. """def __init__(self): """ Initialize the parts of a response to nothing. """ self.headers = [] self.status = None self.content = Nonedef add_header(self, headerKey, headerValue): """ Adds a new header to the response """ self.headers.append(f"{headerKey}: {headerValue}")def set_status(self, statusCode, statusMessage): """ Sets the status of the response """ self.status = f"HTTP/1.1 {statusCode} {statusMessage}"def set_content(self, content): """ Sets `self.content` to the bytes of the content """ if isinstance(content, (bytes, bytearray)): self.content = content else: self.content = content.encode("utf-8")# TODO Complete the build function def build(self):response = self.status response += NEWLINE for i in self.headers: response += i response += NEWLINE response += NEWLINE response = response.encode("utf-8") response += self.contentreturn response """ Returns the utf-8 bytes of the response. Uses the `self.status`, `self.headers` and `self.content` to form an HTTP response in valid formatting per w3c specifications, which can be seen here: https://www.w3.org/Protocols/rfc2616/rfc2616-sec6.html or here: https://www.tutorialspoint.com/http/http_responses.htm Where CRLF is our `NEWLINE` constant. """if __name__ == "__main__": HTTPServer()

六、测试在pycharm里运行如下