github.com/google/go-safeweb@v0.0.0-20231219055052-64d8cfc90fbb/safehttp/handler.go (about)

     1  // Copyright 2020 Google LLC
     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  //	https://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 safehttp
    16  
    17  // Handler responds to an HTTP request.
    18  type Handler interface {
    19  	// ServeHTTP writes the response exactly once, returning the result
    20  	//
    21  	// Except for reading the body, handlers should not modify the provided Request.
    22  	//
    23  	// TODO: Add documentation about error handling when properly implemented.
    24  	ServeHTTP(ResponseWriter, *IncomingRequest) Result
    25  }
    26  
    27  // HandlerFunc is used to convert a function into a Handler.
    28  type HandlerFunc func(ResponseWriter, *IncomingRequest) Result
    29  
    30  // ServeHTTP calls f(w, r).
    31  func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *IncomingRequest) Result {
    32  	return f(w, r)
    33  }
    34  
    35  // StripPrefix returns a handler that serves HTTP requests by removing the given
    36  // prefix from the request URL's Path (and RawPath if set) and invoking the
    37  // handler h.
    38  //
    39  // StripPrefix handles a request for a path that doesn't begin with prefix by
    40  // panicking, as this is a server configuration error. The prefix must match
    41  // exactly (e.g. escaped and unescaped characters are considered different).
    42  func StripPrefix(prefix string, h Handler) Handler {
    43  	if prefix == "" {
    44  		return h
    45  	}
    46  	return HandlerFunc(func(rw ResponseWriter, ir *IncomingRequest) Result {
    47  		ir2, err := ir.WithStrippedURLPrefix(prefix)
    48  		if err != nil {
    49  			panic(err)
    50  		}
    51  		return h.ServeHTTP(rw, ir2)
    52  	})
    53  }