api: Simplify copyObject API, return only error if any.

- Add a new example and update API spec.
- Fix signV2 test being used inside V4 in previous patch.

API.md

@@ -35,6 +35,7 @@ s3Client can be used to perform operations on S3 storage. APIs are described bel
 
 * [`GetObject`](#GetObject)
 * [`PutObject`](#PutObject)
+* [`CopyObject`](#CopyObject)
 * [`StatObject`](#StatObject)
 * [`RemoveObject`](#RemoveObject)
 * [`RemoveIncompleteUpload`](#RemoveIncompleteUpload)
@@ -328,6 +329,42 @@ if err != nil {
 }
 ```
 
+---------------------------------------
+<a name="CopyObject">
+#### CopyObject(bucketName, objectName, objectSource, conditions)
+Copy a source object into a new object with the provided name in the provided bucket.
+
+__Arguments__
+* `bucketName` _string_: name of the bucket
+* `objectName` _string_: name of the object
+* `objectSource` _string_: name of the object source.
+* `conditions` _CopyConditions_: Collection of supported CopyObject conditions. ['x-amz-copy-source', 'x-amz-copy-source-if-match', 'x-amz-copy-source-if-none-match', 'x-amz-copy-source-if-unmodified-since', 'x-amz-copy-source-if-modified-since']
+
+__Example__
+```go
+// All following conditions are allowed and can be combined together.
+
+// Set copy conditions.
+var copyConds = minio.NewCopyConditions()
+// Set modified condition, copy object modified since 2014 April.
+copyConds.SetModified(time.Date(2014, time.April, 0, 0, 0, 0, 0, time.UTC))
+
+// Set unmodified condition, copy object unmodified since 2014 April.
+// copyConds.SetUnmodified(time.Date(2014, time.April, 0, 0, 0, 0, 0, time.UTC))
+
+// Set matching ETag condition, copy object which matches the following ETag.
+// copyConds.SetMatchETag("31624deb84149d2f8ef9c385918b653a")
+
+// Set matching ETag except condition, copy object which does not match the following ETag.
+// copyConds.SetMatchETagExcept("31624deb84149d2f8ef9c385918b653a")
+
+err := s3Client.CopyObject("my-bucketname", "my-objectname", "/my-sourcebucketname/my-sourceobjectname", copyConds)
+if err != nil {
+    fmt.Println(err)
+    return
+}
+```
+
 ---------------------------------------
 <a name="FPutObject">
 #### FPutObject(bucketName, objectName, filePath, contentType)

api-put-object-copy.go

@@ -1,5 +1,5 @@
 /*
- * Minio Go Library for Amazon S3 Compatible Cloud Storage (C) 2015, 2016 Minio, Inc.
+ * Minio Go Library for Amazon S3 Compatible 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.
@@ -19,36 +19,50 @@ package minio
 import "net/http"
 
 // CopyObject - copy a source object into a new object with the provided name in the provided bucket
-func (c Client) CopyObject(bucketName, objectName string, xAmzHeaders http.Header) (copyObjectResult, error) {
+func (c Client) CopyObject(bucketName string, objectName string, objectSource string, cpCond CopyConditions) error {
 	// Input validation.
 	if err := isValidBucketName(bucketName); err != nil {
-		return copyObjectResult{}, err
+		return err
 	}
 	if err := isValidObjectName(objectName); err != nil {
-		return copyObjectResult{}, err
+		return err
 	}
+	if objectSource == "" {
+		return ErrInvalidArgument("Object source cannot be empty.")
+	}
+
+	// customHeaders apply headers.
+	customHeaders := make(http.Header)
+	for _, cond := range cpCond.conditions {
+		customHeaders.Set(cond.key, cond.value)
+	}
+
+	// Set copy source.
+	customHeaders.Set("x-amz-copy-source", objectSource)
 
 	// Execute PUT on objectName.
 	resp, err := c.executeMethod("PUT", requestMetadata{
 		bucketName:   bucketName,
 		objectName:   objectName,
-		customHeader: xAmzHeaders,
+		customHeader: customHeaders,
 	})
 	defer closeResponse(resp)
 	if err != nil {
-		return copyObjectResult{}, err
+		return err
 	}
 	if resp != nil {
 		if resp.StatusCode != http.StatusOK {
-			return copyObjectResult{}, httpRespToErrorResponse(resp, bucketName, objectName)
+			return httpRespToErrorResponse(resp, bucketName, objectName)
 		}
 	}
 
 	// Decode copy response on success.
-	copyObjectResult := copyObjectResult{}
-	err = xmlDecoder(resp.Body, &copyObjectResult)
+	cpObjRes := copyObjectResult{}
+	err = xmlDecoder(resp.Body, &cpObjRes)
 	if err != nil {
-		return copyObjectResult, err
+		return err
 	}
-	return copyObjectResult, nil
+
+	// Return nil on success.
+	return nil
 }

api_functional_v2_test.go

@@ -26,7 +26,6 @@ import (
 	"net/http"
 	"net/url"
 	"os"
-	"strings"
 	"testing"
 	"time"
 
@@ -958,12 +957,18 @@ func TestCopyObjectV2(t *testing.T) {
 			len(buf), n)
 	}
 
-	// Make headers for the copy.
-	xAmzHeaders := make(http.Header)
-	xAmzHeaders.Set("x-amz-copy-source", bucketName+"/"+objectName)
+	// Set copy conditions.
+	copyConds := minio.NewCopyConditions()
+	err = copyConds.SetModified(time.Date(2014, time.April, 0, 0, 0, 0, 0, time.UTC))
+	if err != nil {
+		t.Fatal("Error:", err)
+	}
+
+	// Copy source.
+	copySource := bucketName + "/" + objectName
 
 	// Perform the Copy
-	res, err := c.CopyObject(bucketName+"-copy", objectName+"-copy", xAmzHeaders)
+	err = c.CopyObject(bucketName+"-copy", objectName+"-copy", copySource, copyConds)
 	if err != nil {
 		t.Fatal("Error:", err, bucketName+"-copy", objectName+"-copy")
 	}
@@ -995,13 +1000,6 @@ func TestCopyObjectV2(t *testing.T) {
 		t.Fatalf("Error: ETags do not match, want %v, got %v\n",
 			objInfoCopy.ETag, objInfo.ETag)
 	}
-	// Trim double quotes from copyObjectResult ETag field to compare
-	copyObjectETag := strings.TrimPrefix(res.ETag, "\"")
-	copyObjectETag = strings.TrimSuffix(copyObjectETag, "\"")
-	if copyObjectETag != objInfo.ETag {
-		t.Fatalf("Error: ETags do not match, want %v, got %v\n",
-			objInfo.ETag, copyObjectETag)
-	}
 
 	// Remove all objects and buckets
 	err = c.RemoveObject(bucketName, objectName)

api_functional_v4_test.go

@@ -26,7 +26,6 @@ import (
 	"net/http"
 	"net/url"
 	"os"
-	"strings"
 	"testing"
 	"time"
 
@@ -936,7 +935,7 @@ func TestCopyObject(t *testing.T) {
 	rand.Seed(time.Now().Unix())
 
 	// Instantiate new minio client object
-	c, err := minio.NewV2(
+	c, err := minio.NewV4(
 		"s3.amazonaws.com",
 		os.Getenv("ACCESS_KEY"),
 		os.Getenv("SECRET_KEY"),
@@ -987,12 +986,18 @@ func TestCopyObject(t *testing.T) {
 			len(buf), n)
 	}
 
-	// Make headers for the copy.
-	xAmzHeaders := make(http.Header)
-	xAmzHeaders.Set("x-amz-copy-source", bucketName+"/"+objectName)
+	// Set copy conditions.
+	copyConds := minio.NewCopyConditions()
+	err = copyConds.SetModified(time.Date(2014, time.April, 0, 0, 0, 0, 0, time.UTC))
+	if err != nil {
+		t.Fatal("Error:", err)
+	}
+
+	// Copy source.
+	copySource := bucketName + "/" + objectName
 
 	// Perform the Copy
-	res, err := c.CopyObject(bucketName+"-copy", objectName+"-copy", xAmzHeaders)
+	err = c.CopyObject(bucketName+"-copy", objectName+"-copy", copySource, copyConds)
 	if err != nil {
 		t.Fatal("Error:", err, bucketName+"-copy", objectName+"-copy")
 	}
@@ -1024,13 +1029,6 @@ func TestCopyObject(t *testing.T) {
 		t.Fatalf("Error: ETags do not match, want %v, got %v\n",
 			objInfoCopy.ETag, objInfo.ETag)
 	}
-	// Trim double quotes from copyObjectResult ETag field to compare
-	copyObjectETag := strings.TrimPrefix(res.ETag, "\"")
-	copyObjectETag = strings.TrimSuffix(copyObjectETag, "\"")
-	if copyObjectETag != objInfo.ETag {
-		t.Fatalf("Error: ETags do not match, want %v, got %v\n",
-			objInfo.ETag, copyObjectETag)
-	}
 
 	// Remove all objects and buckets
 	err = c.RemoveObject(bucketName, objectName)

copy-conditions.go

@@ -0,0 +1,97 @@
+/*
+ * Minio Go Library for Amazon S3 Compatible 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 minio
+
+import (
+	"net/http"
+	"time"
+)
+
+// copyCondition explanation:
+// http://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectCOPY.html
+//
+// Example:
+//
+//   copyCondition {
+//       key: "x-amz-copy-if-modified-since",
+//       value: "Tue, 15 Nov 1994 12:45:26 GMT",
+//   }
+//
+type copyCondition struct {
+	key   string
+	value string
+}
+
+// CopyConditions - copy conditions.
+type CopyConditions struct {
+	conditions []copyCondition
+}
+
+// NewCopyConditions - Instantiate new list of conditions.
+func NewCopyConditions() CopyConditions {
+	return CopyConditions{
+		conditions: make([]copyCondition, 0),
+	}
+}
+
+// SetMatchETag - set match etag.
+func (c CopyConditions) SetMatchETag(etag string) error {
+	if etag == "" {
+		return ErrInvalidArgument("ETag cannot be empty.")
+	}
+	c.conditions = append(c.conditions, copyCondition{
+		key:   "x-amz-copy-source-if-match",
+		value: etag,
+	})
+	return nil
+}
+
+// SetMatchETagExcept - set match etag except.
+func (c CopyConditions) SetMatchETagExcept(etag string) error {
+	if etag == "" {
+		return ErrInvalidArgument("ETag cannot be empty.")
+	}
+	c.conditions = append(c.conditions, copyCondition{
+		key:   "x-amz-copy-source-if-none-match",
+		value: etag,
+	})
+	return nil
+}
+
+// SetUnmodified - set unmodified time since.
+func (c CopyConditions) SetUnmodified(modTime time.Time) error {
+	if modTime.IsZero() {
+		return ErrInvalidArgument("Modified since cannot be empty.")
+	}
+	c.conditions = append(c.conditions, copyCondition{
+		key:   "x-amz-copy-source-if-unmodified-since",
+		value: modTime.Format(http.TimeFormat),
+	})
+	return nil
+}
+
+// SetModified - set modified time since.
+func (c CopyConditions) SetModified(modTime time.Time) error {
+	if modTime.IsZero() {
+		return ErrInvalidArgument("Modified since cannot be empty.")
+	}
+	c.conditions = append(c.conditions, copyCondition{
+		key:   "x-amz-copy-source-if-modified-since",
+		value: modTime.Format(http.TimeFormat),
+	})
+	return nil
+}

examples/s3/copyobject.go

@@ -0,0 +1,67 @@
+// +build ignore
+
+/*
+ * Minio Go Library for Amazon S3 Compatible 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 (
+	"log"
+	"time"
+
+	"github.com/minio/minio-go"
+)
+
+func main() {
+	// Note: YOUR-ACCESSKEYID, YOUR-SECRETACCESSKEY, my-testfile, my-bucketname and
+	// my-objectname are dummy values, please replace them with original values.
+
+	// Requests are always secure (HTTPS) by default. Set insecure=true to enable insecure (HTTP) access.
+	// This boolean value is the last argument for New().
+
+	// New returns an Amazon S3 compatible client object. API copatibality (v2 or v4) is automatically
+	// determined based on the Endpoint value.
+	s3Client, err := minio.New("s3.amazonaws.com", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", false)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	// Enable trace.
+	// s3Client.TraceOn(os.Stderr)
+
+	// All following conditions are allowed and can be combined together.
+
+	// Set copy conditions.
+	var copyConds = minio.NewCopyConditions()
+	// Set modified condition, copy object modified since 2014 April.
+	copyConds.SetModified(time.Date(2014, time.April, 0, 0, 0, 0, 0, time.UTC))
+
+	// Set unmodified condition, copy object unmodified since 2014 April.
+	// copyConds.SetUnmodified(time.Date(2014, time.April, 0, 0, 0, 0, 0, time.UTC))
+
+	// Set matching ETag condition, copy object which matches the following ETag.
+	// copyConds.SetMatchETag("31624deb84149d2f8ef9c385918b653a")
+
+	// Set matching ETag except condition, copy object which does not match the following ETag.
+	// copyConds.SetMatchETagExcept("31624deb84149d2f8ef9c385918b653a")
+
+	// Initiate copy object.
+	err = s3Client.CopyObject("my-bucketname", "my-objectname", "/my-sourcebucketname/my-sourceobjectname", copyConds)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	log.Println("Copied source object /my-sourcebucketname/my-sourceobjectname to destination /my-bucketname/my-objectname Successfully.")
+}