feat(web基础): 新增零基础Web开发课程

2026-08-20 16:14:29 +08:00
parent bf1f7042a9
commit 0c3d6402ea
19 changed files with 2005 additions and 8 deletions
@@ -0,0 +1,140 @@
+"""第5-6课标准示例：启动本地HTTP服务并自动调用图书接口。"""
+
+import json
+from http import HTTPStatus
+from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from threading import Thread
+from urllib.error import HTTPError
+from urllib.request import Request, urlopen
+
+
+class BookApiHandler(BaseHTTPRequestHandler):
+    """处理本课图书查询和新增请求的最小HTTP处理器。"""
+
+    # 本课不连接数据库，使用类属性保存当前程序运行期间的图书。
+    # 程序退出后这份列表会消失，再次运行时会重新从一条图书开始。
+    books = [{"id": 1, "title": "Python入门"}]
+
+    def send_json(
+        self,
+        status: HTTPStatus,
+        data: dict | list,
+        extra_headers: dict | None = None,
+    ) -> None:
+        """把Python对象转换为UTF-8 JSON响应。"""
+
+        # HTTP连接传输的是字节，因此先生成JSON字符串，再编码成UTF-8字节。
+        response_body = json.dumps(data, ensure_ascii=False).encode("utf-8")
+        self.send_response(status)
+        self.send_header("Content-Type", "application/json; charset=utf-8")
+        # Content-Length必须填写字节数量，不能直接计算中文字符串的字符数。
+        self.send_header("Content-Length", str(len(response_body)))
+        if extra_headers is not None:
+            for header_name, header_value in extra_headers.items():
+                self.send_header(header_name, header_value)
+        self.end_headers()
+        self.wfile.write(response_body)
+
+    def do_GET(self) -> None:
+        """处理GET /books，并拒绝未知路径。"""
+
+        # 标准库收到GET请求后会自动调用本方法，self.path保存请求目标。
+        if self.path == "/books":
+            self.send_json(HTTPStatus.OK, {"items": self.books})
+            return
+        self.send_json(HTTPStatus.NOT_FOUND, {"message": "资源不存在"})
+
+    def do_POST(self) -> None:
+        """处理POST /books，校验JSON并创建图书。"""
+
+        if self.path != "/books":
+            self.send_json(HTTPStatus.NOT_FOUND, {"message": "资源不存在"})
+            return
+
+        try:
+            # Content-Length告诉服务器本次请求体一共有多少字节。
+            content_length = int(self.headers.get("Content-Length", "0"))
+            request_body = self.rfile.read(content_length).decode("utf-8")
+            request_data = json.loads(request_body)
+        except (UnicodeDecodeError, json.JSONDecodeError):
+            self.send_json(HTTPStatus.BAD_REQUEST, {"message": "JSON格式错误"})
+            return
+
+        title = request_data.get("title")
+        if not isinstance(title, str) or not title.strip():
+            self.send_json(
+                HTTPStatus.UNPROCESSABLE_CONTENT,
+                {"message": "书名不能为空"},
+            )
+            return
+
+        # 本课用列表长度模拟生成编号；真实项目通常由数据库生成主键。
+        book = {"id": len(self.books) + 1, "title": title.strip()}
+        self.books.append(book)
+        self.send_json(
+            HTTPStatus.CREATED,
+            book,
+            {"Location": f"/books/{book['id']}"},
+        )
+
+    def log_message(self, format_text: str, *args: object) -> None:
+        """关闭标准库默认访问日志，让教学输出保持清晰。"""
+
+
+def send_request(
+    url: str,
+    method: str = "GET",
+    data: dict | None = None,
+) -> None:
+    """作为客户端发送HTTP请求并输出响应。"""
+
+    request_body = None
+    headers = {"Accept": "application/json"}
+    if data is not None:
+        request_body = json.dumps(data, ensure_ascii=False).encode("utf-8")
+        headers["Content-Type"] = "application/json; charset=utf-8"
+
+    # Request只负责描述请求；urlopen()执行时才真正连接服务器并发送请求。
+    request = Request(url, data=request_body, headers=headers, method=method)
+    try:
+        with urlopen(request, timeout=3) as response:
+            response_text = response.read().decode("utf-8")
+            print(f"{method} {request.full_url} -> {response.status}")
+            print(f"响应体：{response_text}")
+    except HTTPError as error:
+        response_text = error.read().decode("utf-8")
+        print(f"{method} {request.full_url} -> {error.code}")
+        print(f"响应体：{response_text}")
+
+
+def main() -> None:
+    """在随机本地端口启动服务，完成调用后安全关闭。"""
+
+    # 127.0.0.1限制为本机访问；端口0表示让操作系统选择可用端口。
+    server = ThreadingHTTPServer(("127.0.0.1", 0), BookApiHandler)
+    # 服务器需要持续等待请求，因此放入后台线程；主线程继续充当客户端。
+    server_thread = Thread(target=server.serve_forever, daemon=True)
+    server_thread.start()
+    host, port = server.server_address
+    base_url = f"http://{host}:{port}"
+    print(f"本地服务已启动：{base_url}")
+
+    try:
+        send_request(f"{base_url}/books")
+        send_request(
+            f"{base_url}/books",
+            method="POST",
+            data={"title": "HTTP接口实践"},
+        )
+        send_request(f"{base_url}/books")
+        send_request(f"{base_url}/missing")
+    finally:
+        # 即使某次请求失败，也必须释放监听端口并等待后台线程退出。
+        server.shutdown()
+        server.server_close()
+        server_thread.join()
+        print("本地服务已关闭。")
+
+
+if __name__ == "__main__":
+    main()