minio/cmd/generic-handlers.go
Harshavardhana 62f8343879 Add constants for commonly used values. (#3588)
This is a consolidation effort, avoiding usage
of naked strings in codebase. Whenever possible
use constants which can be repurposed elsewhere.

This also fixes `goconst ./...` reported issues.
2017-01-18 12:24:34 -08:00

359 lines
10 KiB
Go

/*
* Minio Cloud Storage, (C) 2015, 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"net/http"
"path"
"strings"
"time"
humanize "github.com/dustin/go-humanize"
router "github.com/gorilla/mux"
"github.com/rs/cors"
)
// HandlerFunc - useful to chain different middleware http.Handler
type HandlerFunc func(http.Handler) http.Handler
func registerHandlers(mux *router.Router, handlerFns ...HandlerFunc) http.Handler {
var f http.Handler
f = mux
for _, hFn := range handlerFns {
f = hFn(f)
}
return f
}
// Adds limiting body size middleware
// Maximum allowed form data field values. 64MiB is a guessed practical value
// which is more than enough to accommodate any form data fields and headers.
const requestFormDataSize = 64 * humanize.MiByte
// For any HTTP request, request body should be not more than 5GiB + requestFormDataSize
// where, 5GiB is the maximum allowed object size for object upload.
const requestMaxBodySize = 5*humanize.GiByte + requestFormDataSize
type requestSizeLimitHandler struct {
handler http.Handler
maxBodySize int64
}
func setRequestSizeLimitHandler(h http.Handler) http.Handler {
return requestSizeLimitHandler{handler: h, maxBodySize: requestMaxBodySize}
}
func (h requestSizeLimitHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// Restricting read data to a given maximum length
r.Body = http.MaxBytesReader(w, r.Body, h.maxBodySize)
h.handler.ServeHTTP(w, r)
}
// Reserved bucket.
const (
reservedBucket = "/minio"
)
// Adds redirect rules for incoming requests.
type redirectHandler struct {
handler http.Handler
}
func setBrowserRedirectHandler(h http.Handler) http.Handler {
return redirectHandler{handler: h}
}
// Fetch redirect location if urlPath satisfies certain
// criteria. Some special names are considered to be
// redirectable, this is purely internal function and
// serves only limited purpose on redirect-handler for
// browser requests.
func getRedirectLocation(urlPath string) (rLocation string) {
if urlPath == reservedBucket {
rLocation = reservedBucket + "/"
}
if contains([]string{
"/",
"/webrpc",
"/login",
"/favicon.ico",
}, urlPath) {
rLocation = reservedBucket + urlPath
}
return rLocation
}
// guessIsBrowserReq - returns true if the request is browser.
// This implementation just validates user-agent and
// looks for "Mozilla" string. This is no way certifiable
// way to know if the request really came from a browser
// since User-Agent's can be arbitrary. But this is just
// a best effort function.
func guessIsBrowserReq(req *http.Request) bool {
if req == nil {
return false
}
return strings.Contains(req.Header.Get("User-Agent"), "Mozilla")
}
func (h redirectHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
aType := getRequestAuthType(r)
// Re-direct only for JWT and anonymous requests from browser.
if aType == authTypeJWT || aType == authTypeAnonymous {
// Re-direction is handled specifically for browser requests.
if guessIsBrowserReq(r) && globalIsBrowserEnabled {
// Fetch the redirect location if any.
redirectLocation := getRedirectLocation(r.URL.Path)
if redirectLocation != "" {
// Employ a temporary re-direct.
http.Redirect(w, r, redirectLocation, http.StatusTemporaryRedirect)
return
}
}
}
h.handler.ServeHTTP(w, r)
}
// Adds Cache-Control header
type cacheControlHandler struct {
handler http.Handler
}
func setBrowserCacheControlHandler(h http.Handler) http.Handler {
return cacheControlHandler{h}
}
func (h cacheControlHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.Method == httpGET && guessIsBrowserReq(r) && globalIsBrowserEnabled {
// For all browser requests set appropriate Cache-Control policies
if strings.HasPrefix(r.URL.Path, reservedBucket+"/") {
if strings.HasSuffix(r.URL.Path, ".js") || r.URL.Path == reservedBucket+"/favicon.ico" {
// For assets set cache expiry of one year. For each release, the name
// of the asset name will change and hence it can not be served from cache.
w.Header().Set("Cache-Control", "max-age=31536000")
} else {
// For non asset requests we serve index.html which will never be cached.
w.Header().Set("Cache-Control", "no-store")
}
}
}
h.handler.ServeHTTP(w, r)
}
// Adds verification for incoming paths.
type minioPrivateBucketHandler struct {
handler http.Handler
reservedBucket string
}
func setPrivateBucketHandler(h http.Handler) http.Handler {
return minioPrivateBucketHandler{handler: h, reservedBucket: reservedBucket}
}
func (h minioPrivateBucketHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
// For all non browser requests, reject access to 'reservedBucket'.
if !guessIsBrowserReq(r) && path.Clean(r.URL.Path) == reservedBucket {
writeErrorResponse(w, ErrAllAccessDisabled, r.URL)
return
}
h.handler.ServeHTTP(w, r)
}
type timeValidityHandler struct {
handler http.Handler
}
// setTimeValidityHandler to validate parsable time over http header
func setTimeValidityHandler(h http.Handler) http.Handler {
return timeValidityHandler{h}
}
// Supported Amz date formats.
var amzDateFormats = []string{
time.RFC1123,
time.RFC1123Z,
iso8601Format,
// Add new AMZ date formats here.
}
// Supported Amz date headers.
var amzDateHeaders = []string{
"x-amz-date",
"date",
}
// parseAmzDate - parses date string into supported amz date formats.
func parseAmzDate(amzDateStr string) (amzDate time.Time, apiErr APIErrorCode) {
for _, dateFormat := range amzDateFormats {
amzDate, err := time.Parse(dateFormat, amzDateStr)
if err == nil {
return amzDate, ErrNone
}
}
return time.Time{}, ErrMalformedDate
}
// parseAmzDateHeader - parses supported amz date headers, in
// supported amz date formats.
func parseAmzDateHeader(req *http.Request) (time.Time, APIErrorCode) {
for _, amzDateHeader := range amzDateHeaders {
amzDateStr := req.Header.Get(http.CanonicalHeaderKey(amzDateHeader))
if amzDateStr != "" {
return parseAmzDate(amzDateStr)
}
}
// Date header missing.
return time.Time{}, ErrMissingDateHeader
}
func (h timeValidityHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
aType := getRequestAuthType(r)
if aType == authTypeSigned || aType == authTypeSignedV2 || aType == authTypeStreamingSigned {
// Verify if date headers are set, if not reject the request
amzDate, apiErr := parseAmzDateHeader(r)
if apiErr != ErrNone {
// All our internal APIs are sensitive towards Date
// header, for all requests where Date header is not
// present we will reject such clients.
writeErrorResponse(w, apiErr, r.URL)
return
}
// Verify if the request date header is shifted by less than globalMaxSkewTime parameter in the past
// or in the future, reject request otherwise.
curTime := time.Now().UTC()
if curTime.Sub(amzDate) > globalMaxSkewTime || amzDate.Sub(curTime) > globalMaxSkewTime {
writeErrorResponse(w, ErrRequestTimeTooSkewed, r.URL)
return
}
}
h.handler.ServeHTTP(w, r)
}
type resourceHandler struct {
handler http.Handler
}
// List of http methods.
const (
httpGET = "GET"
httpPUT = "PUT"
httpHEAD = "HEAD"
httpPOST = "POST"
httpDELETE = "DELETE"
httpOPTIONS = "OPTIONS"
)
// List of default allowable HTTP methods.
var defaultAllowableHTTPMethods = []string{
httpGET,
httpPUT,
httpHEAD,
httpPOST,
httpDELETE,
httpOPTIONS,
}
// setCorsHandler handler for CORS (Cross Origin Resource Sharing)
func setCorsHandler(h http.Handler) http.Handler {
c := cors.New(cors.Options{
AllowedOrigins: []string{"*"},
AllowedMethods: defaultAllowableHTTPMethods,
AllowedHeaders: []string{"*"},
ExposedHeaders: []string{"ETag"},
})
return c.Handler(h)
}
// setIgnoreResourcesHandler -
// Ignore resources handler is wrapper handler used for API request resource validation
// Since we do not support all the S3 queries, it is necessary for us to throw back a
// valid error message indicating that requested feature is not implemented.
func setIgnoreResourcesHandler(h http.Handler) http.Handler {
return resourceHandler{h}
}
// Checks requests for not implemented Bucket resources
func ignoreNotImplementedBucketResources(req *http.Request) bool {
for name := range req.URL.Query() {
if notimplementedBucketResourceNames[name] {
return true
}
}
return false
}
// Checks requests for not implemented Object resources
func ignoreNotImplementedObjectResources(req *http.Request) bool {
for name := range req.URL.Query() {
if notimplementedObjectResourceNames[name] {
return true
}
}
return false
}
// List of not implemented bucket queries
var notimplementedBucketResourceNames = map[string]bool{
"acl": true,
"cors": true,
"lifecycle": true,
"logging": true,
"replication": true,
"tagging": true,
"versions": true,
"requestPayment": true,
"versioning": true,
"website": true,
}
// List of not implemented object queries
var notimplementedObjectResourceNames = map[string]bool{
"torrent": true,
"acl": true,
"policy": true,
}
// Resource handler ServeHTTP() wrapper
func (h resourceHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
bucketName, objectName := urlPath2BucketObjectName(r.URL)
// If bucketName is present and not objectName check for bucket level resource queries.
if bucketName != "" && objectName == "" {
if ignoreNotImplementedBucketResources(r) {
writeErrorResponse(w, ErrNotImplemented, r.URL)
return
}
}
// If bucketName and objectName are present check for its resource queries.
if bucketName != "" && objectName != "" {
if ignoreNotImplementedObjectResources(r) {
writeErrorResponse(w, ErrNotImplemented, r.URL)
return
}
}
// A put method on path "/" doesn't make sense, ignore it.
if r.Method == httpPUT && r.URL.Path == "/" {
writeErrorResponse(w, ErrNotImplemented, r.URL)
return
}
// Serve HTTP.
h.handler.ServeHTTP(w, r)
}