github.com/rohankumardubey/aresdb@v0.0.2-0.20190517170215-e54e3ca06b9c/api/panic_handler.go (about)

     1  //  Copyright (c) 2017-2018 Uber Technologies, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package api
    16  
    17  import (
    18  	"net/http"
    19  )
    20  
    21  // PanicHandler is a wrapper handler for handling panic in http request handling
    22  type PanicHandler struct {
    23  	handler http.Handler
    24  }
    25  
    26  // WithPanicHandling will apply panic handler to regular http handler.
    27  func WithPanicHandling(handler http.Handler) PanicHandler {
    28  	return PanicHandler{
    29  		handler: handler,
    30  	}
    31  }
    32  
    33  // ServeHTTP serves http request for PanicHandler.
    34  func (handler PanicHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
    35  	defer func() {
    36  		if r := recover(); r != nil {
    37  			rw.WriteHeader(http.StatusInternalServerError)
    38  			switch e := r.(type) {
    39  			case error:
    40  				rw.Write([]byte(e.Error()))
    41  			case string:
    42  				rw.Write([]byte(e))
    43  			default:
    44  				rw.Write([]byte("Unknown Panic"))
    45  			}
    46  		}
    47  	}()
    48  	handler.handler.ServeHTTP(rw, r)
    49  }