package restful // Copyright 2013 Ernest Micklei. All rights reserved. // Use of this source code is governed by a license // that can be found in the LICENSE file. import ( "bytes" "errors" "fmt" "net/http" "os" "runtime" "strings" "sync" "github.com/emicklei/go-restful/log" ) // Container holds a collection of WebServices and a http.ServeMux to dispatch http requests. // The requests are further dispatched to routes of WebServices using a RouteSelector 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 (RouterJSR311 is a slower alternative) contentEncodingEnabled bool // default is false } // NewContainer creates a new Container using a new ServeMux and default router (CurlyRouter) func NewContainer() *Container { return &Container{ webServices: []*WebService{}, ServeMux: http.NewServeMux(), isRegisteredOnRoot: false, containerFilters: []FilterFunction{}, doNotRecover: true, recoverHandleFunc: logStackOnRecover, serviceErrorHandleFunc: writeServiceError, router: CurlyRouter{}, contentEncodingEnabled: false} } // RecoverHandleFunction declares functions that can be used to handle a panic situation. // The first argument is what recover() returns. The second must be used to communicate an error response. type RecoverHandleFunction func(interface{}, http.ResponseWriter) // RecoverHandler changes the default function (logStackOnRecover) to be called // when a panic is detected. DoNotRecover must be have its default value (=false). func (c *Container) RecoverHandler(handler RecoverHandleFunction) { c.recoverHandleFunc = handler } // ServiceErrorHandleFunction declares functions that can be used to handle a service error situation. // The first argument is the service error, the second is the request that resulted in the error and // the third must be used to communicate an error response. type ServiceErrorHandleFunction func(ServiceError, *Request, *Response) // ServiceErrorHandler changes the default function (writeServiceError) to be called // when a ServiceError is detected. func (c *Container) ServiceErrorHandler(handler ServiceErrorHandleFunction) { c.serviceErrorHandleFunc = handler } // DoNotRecover controls whether panics will be caught to return HTTP 500. // If set to true, Route functions are responsible for handling any error situation. // Default value is true. func (c *Container) DoNotRecover(doNot bool) { c.doNotRecover = doNot } // Router changes the default Router (currently CurlyRouter) func (c *Container) Router(aRouter RouteSelector) { c.router = aRouter } // EnableContentEncoding (default=false) allows for GZIP or DEFLATE encoding of responses. func (c *Container) EnableContentEncoding(enabled bool) { c.contentEncodingEnabled = enabled } // Add a WebService to the Container. It will detect duplicate root paths and exit in that case. func (c *Container) Add(service *WebService) *Container { c.webServicesLock.Lock() defer c.webServicesLock.Unlock() // if rootPath was not set then lazy initialize it if len(service.rootPath) == 0 { service.Path("/") } // cannot have duplicate root paths for _, each := range c.webServices { if each.RootPath() == service.RootPath() { log.Printf("WebService with duplicate root path detected:['%v']", each) os.Exit(1) } } // If not registered on root then add specific mapping if !c.isRegisteredOnRoot { c.isRegisteredOnRoot = c.addHandler(service, c.ServeMux) } c.webServices = append(c.webServices, service) return c } // addHandler may set a new HandleFunc for the serveMux // this function must run inside the critical region protected by the webServicesLock. // returns true if the function was registered on root ("/") func (c *Container) addHandler(service *WebService, serveMux *http.ServeMux) bool { pattern := fixedPrefixPath(service.RootPath()) // check if root path registration is needed if "/" == pattern || "" == pattern { serveMux.HandleFunc("/", c.dispatch) return true } // detect if registration already exists alreadyMapped := false for _, each := range c.webServices { if each.RootPath() == service.RootPath() { alreadyMapped = true break } } if !alreadyMapped { serveMux.HandleFunc(pattern, c.dispatch) if !strings.HasSuffix(pattern, "/") { serveMux.HandleFunc(pattern+"/", c.dispatch) } } return false } func (c *Container) Remove(ws *WebService) error { if c.ServeMux == http.DefaultServeMux { errMsg := fmt.Sprintf("cannot remove a WebService from a Container using the DefaultServeMux: ['%v']", ws) log.Print(errMsg) return errors.New(errMsg) } c.webServicesLock.Lock() defer c.webServicesLock.Unlock() // build a new ServeMux and re-register all WebServices newServeMux := http.NewServeMux() newServices := []*WebService{} newIsRegisteredOnRoot := false for _, each := range c.webServices { if each.rootPath != ws.rootPath { // If not registered on root then add specific mapping if !newIsRegisteredOnRoot { newIsRegisteredOnRoot = c.addHandler(each, newServeMux) } newServices = append(newServices, each) } } c.webServices, c.ServeMux, c.isRegisteredOnRoot = newServices, newServeMux, newIsRegisteredOnRoot return nil } // logStackOnRecover is the default RecoverHandleFunction and is called // when DoNotRecover is false and the recoverHandleFunc is not set for the container. // Default implementation logs the stacktrace and writes the stacktrace on the response. // This may be a security issue as it exposes sourcecode information. func logStackOnRecover(panicReason interface{}, httpWriter http.ResponseWriter) { var buffer bytes.Buffer buffer.WriteString(fmt.Sprintf("recover from panic situation: - %v\r\n", panicReason)) for i := 2; ; i += 1 { _, file, line, ok := runtime.Caller(i) if !ok { break } buffer.WriteString(fmt.Sprintf(" %s:%d\r\n", file, line)) } log.Print(buffer.String()) httpWriter.WriteHeader(http.StatusInternalServerError) httpWriter.Write(buffer.Bytes()) } // writeServiceError is the default ServiceErrorHandleFunction and is called // when a ServiceError is returned during route selection. Default implementation // calls resp.WriteErrorString(err.Code, err.Message) func writeServiceError(err ServiceError, req *Request, resp *Response) { resp.WriteErrorString(err.Code, err.Message) } // Dispatch the incoming Http Request to a matching WebService. func (c *Container) Dispatch(httpWriter http.ResponseWriter, httpRequest *http.Request) { if httpWriter == nil { panic("httpWriter cannot be nil") } if httpRequest == nil { panic("httpRequest cannot be nil") } c.dispatch(httpWriter, httpRequest) } // Dispatch the incoming Http Request to a matching WebService. func (c *Container) dispatch(httpWriter http.ResponseWriter, httpRequest *http.Request) { writer := httpWriter // CompressingResponseWriter should be closed after all operations are done defer func() { if compressWriter, ok := writer.(*CompressingResponseWriter); ok { compressWriter.Close() } }() // Instal panic recovery unless told otherwise if !c.doNotRecover { // catch all for 500 response defer func() { if r := recover(); r != nil { c.recoverHandleFunc(r, writer) return } }() } // Detect if compression is needed // assume without compression, test for override if c.contentEncodingEnabled { doCompress, encoding := wantsCompressedResponse(httpRequest) if doCompress { var err error writer, err = NewCompressingResponseWriter(httpWriter, encoding) if err != nil { log.Print("unable to install compressor: ", err) httpWriter.WriteHeader(http.StatusInternalServerError) return } } } // Find best match Route ; err is non nil if no match was found var webService *WebService var route *Route var err error func() { c.webServicesLock.RLock() defer c.webServicesLock.RUnlock() webService, route, err = c.router.SelectRoute( c.webServices, httpRequest) }() if err != nil { // a non-200 response has already been written // run container filters anyway ; they should not touch the response... chain := FilterChain{Filters: c.containerFilters, Target: func(req *Request, resp *Response) { switch err.(type) { case ServiceError: ser := err.(ServiceError) c.serviceErrorHandleFunc(ser, req, resp) } // TODO }} chain.ProcessFilter(NewRequest(httpRequest), NewResponse(writer)) return } pathProcessor, routerProcessesPath := c.router.(PathProcessor) if !routerProcessesPath { pathProcessor = defaultPathProcessor{} } pathParams := pathProcessor.ExtractParameters(route, webService, httpRequest.URL.Path) wrappedRequest, wrappedResponse := route.wrapRequestResponse(writer, httpRequest, pathParams) // pass through filters (if any) if len(c.containerFilters)+len(webService.filters)+len(route.Filters) > 0 { // compose filter chain allFilters := []FilterFunction{} allFilters = append(allFilters, c.containerFilters...) allFilters = append(allFilters, webService.filters...) allFilters = append(allFilters, route.Filters...) 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 { // no filters, handle request by route route.Function(wrappedRequest, wrappedResponse) } } // fixedPrefixPath returns the fixed part of the partspec ; it may include template vars {} func fixedPrefixPath(pathspec string) string { varBegin := strings.Index(pathspec, "{") if -1 == varBegin { return pathspec } return pathspec[:varBegin] } // ServeHTTP implements net/http.Handler therefore a Container can be a Handler in a http.Server func (c *Container) ServeHTTP(httpwriter http.ResponseWriter, httpRequest *http.Request) { c.ServeMux.ServeHTTP(httpwriter, httpRequest) } // Handle registers the handler for the given pattern. If a handler already exists for pattern, Handle panics. func (c *Container) Handle(pattern string, handler http.Handler) { c.ServeMux.Handle(pattern, handler) } // HandleWithFilter registers the handler for the given pattern. // Container's filter chain is applied for handler. // If a handler already exists for pattern, HandleWithFilter panics. func (c *Container) HandleWithFilter(pattern string, handler http.Handler) { f := func(httpResponse http.ResponseWriter, httpRequest *http.Request) { if len(c.containerFilters) == 0 { handler.ServeHTTP(httpResponse, httpRequest) return } chain := FilterChain{Filters: c.containerFilters, Target: func(req *Request, resp *Response) { handler.ServeHTTP(httpResponse, httpRequest) }} chain.ProcessFilter(NewRequest(httpRequest), NewResponse(httpResponse)) } c.Handle(pattern, http.HandlerFunc(f)) } // Filter appends a container FilterFunction. These are called before dispatching // a http.Request to a WebService from the container func (c *Container) Filter(filter FilterFunction) { c.containerFilters = append(c.containerFilters, filter) } // RegisteredWebServices returns the collections of added WebServices func (c *Container) RegisteredWebServices() []*WebService { c.webServicesLock.RLock() defer c.webServicesLock.RUnlock() result := make([]*WebService, len(c.webServices)) for ix := range c.webServices { result[ix] = c.webServices[ix] } return result } // computeAllowedMethods returns a list of HTTP methods that are valid for a Request func (c *Container) computeAllowedMethods(req *Request) []string { // Go through all RegisteredWebServices() and all its Routes to collect the options methods := []string{} requestPath := req.Request.URL.Path for _, ws := range c.RegisteredWebServices() { matches := ws.pathExpr.Matcher.FindStringSubmatch(requestPath) if matches != nil { finalMatch := matches[len(matches)-1] for _, rt := range ws.Routes() { matches := rt.pathExpr.Matcher.FindStringSubmatch(finalMatch) if matches != nil { lastMatch := matches[len(matches)-1] if lastMatch == "" || lastMatch == "/" { // do not include if value is neither empty nor ‘/’. methods = append(methods, rt.Method) } } } } } // methods = append(methods, "OPTIONS") not sure about this return methods } // newBasicRequestResponse creates a pair of Request,Response from its http versions. // It is basic because no parameter or (produces) content-type information is given. func newBasicRequestResponse(httpWriter http.ResponseWriter, httpRequest *http.Request) (*Request, *Response) { resp := NewResponse(httpWriter) resp.requestAccept = httpRequest.Header.Get(HEADER_Accept) return NewRequest(httpRequest), resp }