api: Requests should be differentiated if possible based on http router. (#2219)

In current master ListObjectsV2 was merged into ListObjectsHandler
which also implements V1 API as well.

Move the detection of ListObject types to its rightful place
in http router.

bucket-handlers-listobjects.go

@@ -0,0 +1,167 @@
+/*
+ * Minio Cloud Storage, (C) 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 main
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gorilla/mux"
+)
+
+// Validate all the ListObjects query arguments, returns an APIErrorCode
+// if one of the args do not meet the required conditions.
+// Special conditions required by Minio server are as below
+// - delimiter if set should be equal to '/', otherwise the request is rejected.
+// - marker if set should have a common prefix with 'prefix' param, otherwise
+//   the request is rejected.
+func listObjectsValidateArgs(prefix, marker, delimiter string, maxKeys int) APIErrorCode {
+	// Max keys cannot be negative.
+	if maxKeys < 0 {
+		return ErrInvalidMaxKeys
+	}
+
+	/// Minio special conditions for ListObjects.
+
+	// Verify if delimiter is anything other than '/', which we do not support.
+	if delimiter != "" && delimiter != "/" {
+		return ErrNotImplemented
+	}
+	// Marker is set validate pre-condition.
+	if marker != "" {
+		// Marker not common with prefix is not implemented.
+		if !strings.HasPrefix(marker, prefix) {
+			return ErrNotImplemented
+		}
+	}
+	// Success.
+	return ErrNone
+}
+
+// ListObjectsV2Handler - GET Bucket (List Objects) Version 2.
+// --------------------------
+// This implementation of the GET operation returns some or all (up to 1000)
+// of the objects in a bucket. You can use the request parameters as selection
+// criteria to return a subset of the objects in a bucket.
+//
+// NOTE: It is recommended that this API to be used for application development.
+// Minio continues to support ListObjectsV1 for supporting legacy tools.
+func (api objectAPIHandlers) ListObjectsV2Handler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucket := vars["bucket"]
+
+	switch getRequestAuthType(r) {
+	default:
+		// For all unknown auth types return error.
+		writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
+		return
+	case authTypeAnonymous:
+		// http://docs.aws.amazon.com/AmazonS3/latest/dev/using-with-s3-actions.html
+		if s3Error := enforceBucketPolicy("s3:ListBucket", bucket, r.URL); s3Error != ErrNone {
+			writeErrorResponse(w, r, s3Error, r.URL.Path)
+			return
+		}
+	case authTypeSigned, authTypePresigned:
+		if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
+			writeErrorResponse(w, r, s3Error, r.URL.Path)
+			return
+		}
+	}
+	// Extract all the listObjectsV2 query params to their native values.
+	prefix, token, startAfter, delimiter, maxKeys, _ := getListObjectsV2Args(r.URL.Query())
+
+	// In ListObjectsV2 'continuation-token' is the marker.
+	marker := token
+	// Check if 'continuation-token' is empty.
+	if token == "" {
+		// Then we need to use 'start-after' as marker instead.
+		marker = startAfter
+	}
+	// Validate all the query params before beginning to serve the request.
+	if s3Error := listObjectsValidateArgs(prefix, marker, delimiter, maxKeys); s3Error != ErrNone {
+		writeErrorResponse(w, r, s3Error, r.URL.Path)
+		return
+	}
+	// Inititate a list objects operation based on the input params.
+	// On success would return back ListObjectsInfo object to be
+	// marshalled into S3 compatible XML header.
+	listObjectsInfo, err := api.ObjectAPI.ListObjects(bucket, prefix, marker, delimiter, maxKeys)
+	if err != nil {
+		errorIf(err, "Unable to list objects.")
+		writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
+		return
+	}
+
+	response := generateListObjectsV2Response(bucket, prefix, token, startAfter, delimiter, maxKeys, listObjectsInfo)
+	// Write headers
+	setCommonHeaders(w)
+	// Write success response.
+	writeSuccessResponse(w, encodeResponse(response))
+}
+
+// ListObjectsV1Handler - GET Bucket (List Objects) Version 1.
+// --------------------------
+// This implementation of the GET operation returns some or all (up to 1000)
+// of the objects in a bucket. You can use the request parameters as selection
+// criteria to return a subset of the objects in a bucket.
+//
+func (api objectAPIHandlers) ListObjectsV1Handler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	bucket := vars["bucket"]
+
+	switch getRequestAuthType(r) {
+	default:
+		// For all unknown auth types return error.
+		writeErrorResponse(w, r, ErrAccessDenied, r.URL.Path)
+		return
+	case authTypeAnonymous:
+		// http://docs.aws.amazon.com/AmazonS3/latest/dev/using-with-s3-actions.html
+		if s3Error := enforceBucketPolicy("s3:ListBucket", bucket, r.URL); s3Error != ErrNone {
+			writeErrorResponse(w, r, s3Error, r.URL.Path)
+			return
+		}
+	case authTypeSigned, authTypePresigned:
+		if s3Error := isReqAuthenticated(r); s3Error != ErrNone {
+			writeErrorResponse(w, r, s3Error, r.URL.Path)
+			return
+		}
+	}
+
+	// Extract all the litsObjectsV1 query params to their native values.
+	prefix, marker, delimiter, maxKeys, _ := getListObjectsV1Args(r.URL.Query())
+
+	// Validate all the query params before beginning to serve the request.
+	if s3Error := listObjectsValidateArgs(prefix, marker, delimiter, maxKeys); s3Error != ErrNone {
+		writeErrorResponse(w, r, s3Error, r.URL.Path)
+		return
+	}
+
+	// Inititate a list objects operation based on the input params.
+	// On success would return back ListObjectsInfo object to be
+	// marshalled into S3 compatible XML header.
+	listObjectsInfo, err := api.ObjectAPI.ListObjects(bucket, prefix, marker, delimiter, maxKeys)
+	if err != nil {
+		errorIf(err, "Unable to list objects.")
+		writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
+		return
+	}
+	response := generateListObjectsV1Response(bucket, prefix, marker, delimiter, maxKeys, listObjectsInfo)
+	// Write headers
+	setCommonHeaders(w)
+	// Write success response.
+	writeSuccessResponse(w, encodeResponse(response))
+}