Blob checksum header parsing in HeadObjectResponse

Author: RachelTucker

ds3/ds3Client_test.go

@@ -1911,3 +1911,31 @@ func TestVerifyPhysicalPlacementForObjectsWithFullDetailsSpectraS3(t *testing.T)
     }
     ds3Testing.AssertBool(t, "WriteProtected", false, tape.WriteProtected)
 }
+
+func TestHeadObject(t *testing.T) {
+    bucketName := "bucket1"
+    objectName := "obj1"
+
+    responseHeaders := &http.Header{}
+    responseHeaders.Add("x-amz-meta-key", "value")
+    responseHeaders.Add("ds3-blob-checksum-type", "MD5")
+    responseHeaders.Add("ds3-blob-checksum-offset-0", "4nQGNX4nyz0pi8Hvap79PQ==")
+    responseHeaders.Add("ds3-blob-checksum-offset-10485760", "965Aa0/n8DlO1IwXYFh4bg==")
+    responseHeaders.Add("ds3-blob-checksum-offset-20971520", "iV2OqJaXJ/jmqgRSb1HmFA==")
+
+    response, err := mockedClient(t).
+        Expecting(HTTP_VERB_HEAD, "/" + bucketName + "/" + objectName, &url.Values{}, &http.Header{}, nil).
+        Returning(200, "", responseHeaders).
+        HeadObject(models.NewHeadObjectRequest(bucketName, objectName))
+
+    ds3Testing.AssertNilError(t, err)
+
+    if response.BlobChecksumType != models.CHECKSUM_TYPE_MD5 {
+        t.Fatalf("Expected checksum type to be 'MD5' but was '%s'.", response.BlobChecksumType.String())
+    }
+
+    ds3Testing.AssertInt(t, "# of blob checksums", 3, len(response.BlobChecksums))
+    ds3Testing.AssertString(t, "checksum at offset '0'", "4nQGNX4nyz0pi8Hvap79PQ==", response.BlobChecksums[0])
+    ds3Testing.AssertString(t, "checksum at offset '10485760'", "965Aa0/n8DlO1IwXYFh4bg==", response.BlobChecksums[10485760])
+    ds3Testing.AssertString(t, "checksum at offset '20971520'", "iV2OqJaXJ/jmqgRSb1HmFA==", response.BlobChecksums[20971520])
+}

ds3/models/headObjectResponse.go

@@ -18,7 +18,8 @@ import (
 )
 
 type HeadObjectResponse struct {
-    
+    BlobChecksumType ChecksumType
+    BlobChecksums map[int64]string
     Headers *http.Header
 }
 
@@ -29,7 +30,15 @@ func NewHeadObjectResponse(webResponse WebResponse) (*HeadObjectResponse, error)
 
     switch code := webResponse.StatusCode(); code {
     case 200:
-        return &HeadObjectResponse{Headers: webResponse.Header()}, nil
+        checksumType, err := getBlobChecksumType(webResponse.Header())
+        if err != nil {
+            return nil, err
+        }
+        checksumMap, err := getBlobChecksumMap(webResponse.Header())
+        if err != nil {
+            return nil, err
+        }
+        return &HeadObjectResponse{BlobChecksumType: checksumType, BlobChecksums: checksumMap, Headers: webResponse.Header()}, nil
     default:
         return nil, buildBadStatusCodeError(webResponse, expectedStatusCodes)
     }

ds3/models/responseParsingUtil.go

@@ -14,10 +14,53 @@ package models
 import (
     "strconv"
     "log"
+    "strings"
+    "net/http"
 )
 
 // Contains utils used by model parsers to parse response payloads.
 
+const BLOB_CHECKSUM_TYPE_HEADER string = "ds3-blob-checksum-type"
+const BLOB_CHECKSUM_HEADER string = "ds3-blob-checksum-offset-"
+
+// Parses blob checksum header if exists. This is used by HeadObjectResponse.
+func getBlobChecksumType(headers *http.Header) (ChecksumType, error) {
+    checksumStr := headers.Get(BLOB_CHECKSUM_TYPE_HEADER)
+    if len(checksumStr) == 0 {
+        return NONE, nil
+    }
+    var checksumEnum ChecksumType
+    err := checksumEnum.UnmarshalText([]byte(checksumStr))
+    if err != nil {
+        return UNDEFINED, err
+    }
+    return checksumEnum, nil
+}
+
+// Parses response headers and creates a map of blob offset to blob checksum
+// for all occurrences of headers with prefix defined in BLOB_CHECKSUM_HEADER.
+// This is used by HeadObjectResponse.
+func getBlobChecksumMap(headers *http.Header) (map[int64]string, error) {
+    blobChecksumMap := make(map[int64]string)
+
+    if headers == nil || len(*headers) == 0 {
+        return blobChecksumMap, nil
+    }
+
+    for key := range *headers {
+        if strings.HasPrefix(strings.ToLower(key), strings.ToLower(BLOB_CHECKSUM_HEADER)) {
+            offsetStr := strings.TrimPrefix(strings.ToLower(key), strings.ToLower(BLOB_CHECKSUM_HEADER))
+            offset, err := strconv.ParseInt(offsetStr, 10, 64)
+            if err != nil {
+                return blobChecksumMap, err
+            }
+            blobChecksumMap[offset] = headers.Get(key)
+        }
+    }
+
+    return blobChecksumMap, nil
+}
+
 // Interface defined for spectra defined enums.
 // Used for generic parsing of enums.
 type Ds3Enum interface {