github.com/kaydxh/golang@v0.0.131/go/net/http/http_handler_interceptor.go (about)

     1  /*
     2   *Copyright (c) 2022, kaydxh
     3   *
     4   *Permission is hereby granted, free of charge, to any person obtaining a copy
     5   *of this software and associated documentation files (the "Software"), to deal
     6   *in the Software without restriction, including without limitation the rights
     7   *to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     8   *copies of the Software, and to permit persons to whom the Software is
     9   *furnished to do so, subject to the following conditions:
    10   *
    11   *The above copyright notice and this permission notice shall be included in all
    12   *copies or substantial portions of the Software.
    13   *
    14   *THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    15   *IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    16   *FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    17   *AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    18   *LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    19   *OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    20   *SOFTWARE.
    21   */
    22  package http
    23  
    24  import (
    25  	"net/http"
    26  
    27  	runtime_ "github.com/kaydxh/golang/go/runtime"
    28  )
    29  
    30  type HandlerInterceptor struct {
    31  	//http middleware
    32  	Interceptor func(h http.Handler) http.Handler
    33  }
    34  
    35  func NewHandlerInterceptor(opts ...HandlerInterceptorOption) *HandlerInterceptor {
    36  	handers := &HandlerInterceptor{}
    37  	handers.ApplyOptions(opts...)
    38  	return handers
    39  }
    40  
    41  type HandlerChain struct {
    42  	//invoke before http handler
    43  	PreHandlers []func(w http.ResponseWriter, r *http.Request) error
    44  	Handlers    []HandlerInterceptor
    45  	//invoke after http handler
    46  	PostHandlers []func(w http.ResponseWriter, r *http.Request)
    47  }
    48  
    49  func NewHandlerChain(opts ...HandlerChainOption) *HandlerChain {
    50  	c := &HandlerChain{}
    51  	c.ApplyOptions(opts...)
    52  
    53  	return c
    54  }
    55  
    56  func (c *HandlerChain) WrapH(next http.Handler) http.Handler {
    57  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    58  
    59  		defer runtime_.Recover()
    60  
    61  		for _, preH := range c.PreHandlers {
    62  			err := preH(w, r)
    63  			if err != nil {
    64  				// assume PreHandler already process response by self
    65  				return
    66  			}
    67  		}
    68  
    69  		// reverse iterate handlers, so called handler as registed order
    70  		for i := len(c.Handlers) - 1; i >= 0; i-- {
    71  			// filter interceptor is nil
    72  			if c.Handlers[i].Interceptor != nil {
    73  				next = c.Handlers[i].Interceptor(next)
    74  			}
    75  		}
    76  
    77  		next.ServeHTTP(w, r)
    78  
    79  		for _, postH := range c.PostHandlers {
    80  			postH(w, r)
    81  		}
    82  	})
    83  }