浅谈go-restful框架的使用和实现

func main() {
  ws := new(restful.WebService)
  ws.Path("/users")
  ws.Route(ws.GET("/").To(u.findAllUsers).
    Doc("get all users").
    Metadata(restfulspec.KeyOpenAPITags, tags).
    Writes([]User{}).
    Returns(200, "OK", []User{}))

 container := restful.NewContainer().Add(ws)
 http.ListenAndServe(":8080", container)
}

type Container struct {
  webServicesLock    sync.RWMutex
  webServices      []*WebService
  ServeMux        *http.ServeMux
  isRegisteredOnRoot   bool
  containerFilters    []FilterFunction
  doNotRecover      bool // default is true
  recoverHandleFunc   RecoverHandleFunction
  serviceErrorHandleFunc ServiceErrorHandleFunction
  router         RouteSelector // default is a CurlyRouter
  contentEncodingEnabled bool     // default is false
}

func (c *Container)ServeHTTP(httpwriter http.ResponseWriter, httpRequest *http.Request) {
  c.ServeMux.ServeHTTP(httpwriter, httpRequest)
}

func (c *Container)Add(service *WebService)*Container {
  c.webServicesLock.Lock()
  defer c.webServicesLock.Unlock()
  if !c.isRegisteredOnRoot {
    c.isRegisteredOnRoot = c.addHandler(service, c.ServeMux)
  }
  c.webServices = append(c.webServices, service)
  return c
}

func (c *Container)addHandler(service *WebService, serveMux *http.ServeMux)bool {
  pattern := fixedPrefixPath(service.RootPath())
  serveMux.HandleFunc(pattern, c.dispatch)
}

type WebService struct {
  rootPath    string
  pathExpr    *pathExpression 
  routes     []Route
  produces    []string
  consumes    []string
  pathParameters []*Parameter
  filters    []FilterFunction
  documentation string
  apiVersion   string

  typeNameHandleFunc TypeNameHandleFunction
  dynamicRoutes bool
  routesLock sync.RWMutex
}

func (w *WebService)Route(builder *RouteBuilder)*WebService {
  w.routesLock.Lock()
  defer w.routesLock.Unlock()
  builder.copyDefaults(w.produces, w.consumes)
  w.routes = append(w.routes, builder.Build())
  return w
}

type Route struct {
  Method  string
  Produces []string
  Consumes []string
  Path   string // webservice root path + described path
  Function RouteFunction
  Filters []FilterFunction
  If    []RouteSelectionConditionFunction
  // cached values for dispatching
  relativePath string
  pathParts  []string
  pathExpr   *pathExpression
  // documentation
  Doc           string
  Notes          string
  Operation        string
  ParameterDocs      []*Parameter
  ResponseErrors     map[int]ResponseError
  ReadSample, WriteSample interface{} 
  Metadata map[string]interface{}
  Deprecated bool
}

func (c *Container)dispatch(httpWriter http.ResponseWriter, httpRequest *http.Request) {
  func() {
    c.webServicesLock.RLock()
    defer c.webServicesLock.RUnlock()
    webService, route, err = c.router.SelectRoute(
      c.webServices,
      httpRequest)
  }()

  pathProcessor, routerProcessesPath := c.router.(PathProcessor)
  pathParams := pathProcessor.ExtractParameters(route, webService, httpRequest.URL.Path)
  wrappedRequest, wrappedResponse := route.wrapRequestResponse(writer,
  httpRequest, pathParams)

  if len(c.containerFilters)+len(webService.filters)+len(route.Filters) > 0 {
    chain := FilterChain{Filters: allFilters, Target: func(req *Request, resp *Response) {
      // handle request by route after passing all filters
      route.Function(wrappedRequest, wrappedResponse)
    }}
    chain.ProcessFilter(wrappedRequest, wrappedResponse)
  } else {
    route.Function(wrappedRequest, wrappedResponse)
  }
}

type restfulServer struct {
  microServiceName string
  container    *restful.Container
  ws        *restful.WebService
  opts       server.Options
  mux       sync.RWMutex
  exit       chan chan error
  server      *http.Server
}

func (r *restfulServer)Register(schemainterface{}, options ...server.RegisterOption)(string, error) {
  schemaType := reflect.TypeOf(schema)
  schemaValue := reflect.ValueOf(schema)
  var schemaName string
  tokens := strings.Split(schemaType.String(), ".")
  if len(tokens) >= 1 {
    schemaName = tokens[len(tokens)-1]
  }
  
  routes, err := GetRoutes(schema)
  for _, route := range routes {
    lager.Logger.Infof("Add route path: [%s] Method: [%s] Func: [%s]. ",
      route.Path, route.Method, route.ResourceFuncName)
    method, exist := schemaType.MethodByName(route.ResourceFuncName)
    ...
    handle := func(req *restful.Request, rep *restful.Response) {
      c, err := handler.GetChain(common.Provider, r.opts.ChainName)
      inv := invocation.Invocation{
        MicroServiceName:  config.SelfServiceName,
        SourceMicroService: req.HeaderParameter(common.HeaderSourceName),
        Args:        req,
        Protocol:      common.ProtocolRest,
        SchemaID:      schemaName,
        OperationID:    method.Name,
      }
      bs := NewBaseServer(context.TODO())
      bs.req = req
      bs.resp = rep
      c.Next(&inv, func(ir *invocation.InvocationResponse)error {
        if ir.Err != nil {
          return ir.Err
        }
        method.Func.Call([]reflect.Value{schemaValue, reflect.ValueOf(bs)})
        if bs.resp.StatusCode() >= http.StatusBadRequest {
          return ...
        }
        return nil
      })
    }
 
    switch route.Method {
    case http.MethodGet:
      r.ws.Route(r.ws.GET(route.Path).To(handle).
       Doc(route.ResourceFuncName).
       Operation(route.ResourceFuncName))
    ...
    }
  }
  return reflect.TypeOf(schema).String(), nil
}