diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..0e5fb87 --- /dev/null +++ b/LICENSE @@ -0,0 +1,27 @@ +Copyright (c) 2012 Rodrigo Moraes. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are +met: + + * Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above +copyright notice, this list of conditions and the following disclaimer +in the documentation and/or other materials provided with the +distribution. + * Neither the name of Google Inc. nor the names of its +contributors may be used to endorse or promote products derived from +this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/context.go b/context.go new file mode 100644 index 0000000..fe5b6ad --- /dev/null +++ b/context.go @@ -0,0 +1,101 @@ +// Copyright 2012 The Gorilla Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package context + +import ( + "net/http" + "sync" + "time" +) + +var ( + mutex sync.Mutex + data = make(map[*http.Request]map[interface{}]interface{}) + datat = make(map[*http.Request]int64) +) + +// Set stores a value for a given key in a given request. +func Set(r *http.Request, key, val interface{}) { + mutex.Lock() + defer mutex.Unlock() + if data[r] == nil { + data[r] = make(map[interface{}]interface{}) + datat[r] = time.Now().Unix() + } + data[r][key] = val +} + +// Get returns a value stored for a given key in a given request. +func Get(r *http.Request, key interface{}) interface{} { + mutex.Lock() + defer mutex.Unlock() + if data[r] != nil { + return data[r][key] + } + return nil +} + +// Delete removes a value stored for a given key in a given request. +func Delete(r *http.Request, key interface{}) { + mutex.Lock() + defer mutex.Unlock() + if data[r] != nil { + delete(data[r], key) + } +} + +// Clear removes all values stored for a given request. +// +// This is usually called by a handler wrapper to clean up request +// variables at the end of a request lifetime. See ClearHandler(). +func Clear(r *http.Request) { + mutex.Lock() + defer mutex.Unlock() + clear(r) +} + +// clear is Clear without the lock. +func clear(r *http.Request) { + delete(data, r) + delete(datat, r) +} + +// Purge removes request data stored for longer than maxAge, in seconds. +// It returns the amount of requests removed. +// +// If maxAge <= 0, all request data is removed. +// +// This is only used for sanity check: in case context cleaning was not +// properly set some request data can be kept forever, consuming an increasing +// amount of memory. In case this is detected, Purge() must be called +// periodically until the problem is fixed. +func Purge(maxAge int) int { + mutex.Lock() + defer mutex.Unlock() + count := 0 + if maxAge <= 0 { + count = len(data) + data = make(map[*http.Request]map[interface{}]interface{}) + datat = make(map[*http.Request]int64) + } else { + min := time.Now().Unix() - int64(maxAge) + for r, _ := range data { + if datat[r] < min { + clear(r) + count++ + } + } + } + return count +} + +// ClearHandler wraps an http.Handler and clears request values at the end +// of a request lifetime. +func ClearHandler(h http.Handler) http.Handler { + return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + defer Clear(r) + h.ServeHTTP(w, r) + }) +} diff --git a/context_test.go b/context_test.go new file mode 100644 index 0000000..314a0b6 --- /dev/null +++ b/context_test.go @@ -0,0 +1,52 @@ +// Copyright 2012 The Gorilla Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package context + +import ( + "net/http" + "testing" +) + +type keyType int + +const ( + key1 keyType = iota + key2 +) + +func TestContext(t *testing.T) { + assertEqual := func(val interface{}, exp interface{}) { + if val != exp { + t.Errorf("Expected %v, got %v.", exp, val) + } + } + + r, _ := http.NewRequest("GET", "http://localhost:8080/", nil) + + // Get() + assertEqual(Get(r, key1), nil) + + // Set() + Set(r, key1, "1") + assertEqual(Get(r, key1), "1") + assertEqual(len(data[r]), 1) + + Set(r, key2, "2") + assertEqual(Get(r, key2), "2") + assertEqual(len(data[r]), 2) + + // Delete() + Delete(r, key1) + assertEqual(Get(r, key1), nil) + assertEqual(len(data[r]), 1) + + Delete(r, key2) + assertEqual(Get(r, key2), nil) + assertEqual(len(data[r]), 0) + + // Clear() + Clear(r) + assertEqual(len(data), 0) +} diff --git a/doc.go b/doc.go new file mode 100644 index 0000000..a4cfd50 --- /dev/null +++ b/doc.go @@ -0,0 +1,80 @@ +// Copyright 2012 The Gorilla Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +/* +Package gorilla/context stores values shared during a request lifetime. + +For example, a router can set variables extracted from the URL and later +application handlers can access those values, or it can be used to store +sessions values to be saved at the end of a request. There are several +others common uses. + +The idea was posted by Brad Fitzpatrick to the go-nuts mailing list: + + http://groups.google.com/group/golang-nuts/msg/e2d679d303aa5d53 + +Here's the basic usage: first define the keys that you will need. The key +type is interface{} so a key can be of any type that supports equality. +Here we define a key using a custom int type to avoid name collisions: + + package foo + + import ( + "github.com/gorilla/context" + ) + + type key int + + const MyKey key = 0 + +Then set a variable. Variables are bound to an http.Request object, so you +need a request instance to set a value: + + context.Set(r, MyKey, "bar") + +The application can later access the variable using the same key you provided: + + func MyHandler(w http.ResponseWriter, r *http.Request) { + // val is "bar". + val = context.Get(r, foo.MyKey) + + // ... + } + +And that's all about the basic usage. We discuss some other ideas below. + +Any type can be stored in the context. To enforce a given type, make the key +private and wrap Get() and Set() to accept and return values of a specific +type: + + type key int + + const mykey key = 0 + + // GetMyKey returns a value for this package from the request values. + func GetMyKey(r *http.Request) SomeType { + if rv := context.Get(r, mykey); rv != nil { + return rv.(SomeType) + } + return nil + } + + // SetMyKey sets a value for this package in the request values. + func SetMyKey(r *http.Request, val SomeType) { + context.Set(r, mykey, val) + } + +Variables must be cleared at the end of a request, to remove all values +that were stored. This can be done in an http.Handler, after a request was +served. Just call Clear() passing the request: + + context.Clear(r) + +...or use ClearHandler(), which conveniently wraps an http.Handler to clear +variables at the end of a request lifetime. + +The Router from the package gorilla/mux calls Clear(), so if you are using it +you don't need to clear the context manually. +*/ +package context