first commit

Gateway.py

@@ -0,0 +1,149 @@
+import requests
+import utils
+import json
+import logging as logger
+#import InvalidParameterException
+
+from flask import make_response
+from flask import request
+from ExceptionHandler import *
+
+
+class NoopExceptionHandler(ExceptionHandler):
+
+    DEFAULT_CONTENT = {
+        "error_code": "InternalServerError",
+        "error_message": "",
+        "error_message_chs": "服务器内部错误"
+    }
+
+    def handle(self, e, *args, **kwargs):
+        logger.exception("Unknown exception occurred: %s", e)
+        content = dict(self.DEFAULT_CONTENT)
+        content['error_message'] = e.message
+        return json.dumps(content), 500
+
+
+class GenericGateway(object):
+
+    def __init__(self, app, routes, url_supplier, exception_handler=None):
+        """
+
+        :param app: flask app
+        :type app: flask.Flask
+        :param routes: 路由列表
+        :type routes: list of Route
+        :param url_supplier: 服务名称解析函数，通过service name获取service url: url_supplier(service_name) -> service_url
+        :type url_supplier: function
+        :param exception_handler: exception handle decorator
+        :type exception_handler: ExceptionHandler
+        """
+        if not callable(url_supplier):
+            raise ValueError("service url supplier (url_supplier) must be callable")
+
+        self.app = app
+        self.routes = routes
+        self.url_supplier = url_supplier
+        self.exception_handler = exception_handler or NoopExceptionHandler()
+        self.proxy_list = []
+
+    def get_url(self, service_name):
+        try:
+            return self.url_supplier(service_name)
+        except Exception as e:
+            logger.warning("Failed to get the url of service: %s", service_name, exc_info=True)
+            raise RuntimeError("Failed to get the url of service {}: {}".format(service_name, e))
+
+    def create_request_proxy(self, route):
+
+        logger.info("Register route: %s", route.path)
+
+        def proxy_request(*args, **kwargs):
+
+            upstream_path = route.upstream_path
+            for p_name in route.upstream_params:
+                v = get_params_from_context(p_name, kwargs)
+                upstream_path = utils.replace_placeholder(upstream_path, p_name, v)
+
+            endpoint = self.get_url(route.service_name)
+
+            final_url = "{}{}".format(endpoint, upstream_path)
+            upstream_req_info = dict(
+                url=final_url,
+                method=request.method,
+                params=request.args,
+                data=request.data,
+                files=request.files,
+                headers=request.headers,
+            )
+            if request.form:
+                upstream_req_info['data'] = request.form
+
+            for pipe_handler in route.inbound_pipes():
+                upstream_req_info, args, kwargs = pipe_handler(upstream_req_info, *args, **kwargs)
+
+            content_type = upstream_req_info['headers'].get('Content-Type')
+            if content_type and 'boundary' in content_type:
+                # requests prepare body时，会使重新生成 boundary，headers中旧的 boundary 会导致上游服务无法识别
+                upstream_req_info['headers'] = {k: v for k, v in upstream_req_info['headers'].items()}
+                upstream_req_info['headers'].pop('Content-Type', None)
+                upstream_req_info['headers'].pop('content-type', None)
+            resp = requests.request(**upstream_req_info)
+            status = resp.status_code
+            content = None
+            headers = resp.headers
+
+            for pipe_handler in route.outbound_pipes():
+                resp, headers, status, content = pipe_handler(resp, headers, status, content, *args, **kwargs)
+
+            content = make_response(content or resp.content)
+            for h_name, h_value in (headers or {}).items():
+                content.headers[h_name] = h_value
+
+            return content, status
+
+        # 修改函数名称：Flask route注册使用func name必须唯一
+        proxy_request.__name__ = route.name
+        return proxy_request
+
+    def _register_route(self, route):
+        """
+        :param Route route:
+        """
+        proxy = self.create_request_proxy(route)
+        self.proxy_list.append(
+            self.app.route(route.path, methods=route.methods)(proxy)
+        )
+
+    def register_routes(self):
+        for route in self.routes:
+            self._register_route(route)
+
+
+def get_params_from_context(param_name, kwargs):
+    """按顺序尝试从url参数、headers、args、form、json中获取参数值
+    """
+    payload = {}
+
+    if kwargs and kwargs.get(param_name):
+        payload = kwargs
+    elif request.headers.get(param_name):
+        payload = request.headers
+    elif request.args and request.args.get(param_name):
+        payload = request.args
+    elif request.form and request.form.get(param_name):
+        payload = request.form
+    elif request.data:
+        body = json.loads(request.data)
+        if body and body.get(param_name):
+            payload = body
+
+    try:
+        return payload[param_name]
+    except KeyError as e:
+        # raise InvalidParameterException(
+        #     message="Missing the required params: {}".format(e),
+        #     message_chs="缺少必要的参数 {}".format(e)
+        # )
+
+        print('')