From eac235b2b6a521e32d3b37f51cce4aa3832b7913 Mon Sep 17 00:00:00 2001
From: Rohan Verma <hello@rohanverma.net>
Date: Mon, 19 Jul 2021 13:41:36 +0530
Subject: [PATCH] feat: add support for FileDetails/HEAD API call (#14)

---
 simples3.go      | 95 +++++++++++++++++++++++++++++++++++++++++++++++-
 simples3_test.go | 51 ++++++++++++++++++++++++--
 2 files changed, 141 insertions(+), 5 deletions(-)

diff --git a/simples3.go b/simples3.go
index ed58590..3818ebd 100644
--- a/simples3.go
+++ b/simples3.go
@@ -42,12 +42,33 @@ type S3 struct {
 	URIFormat string
 }
 
-// DownloadInput is passed to FileUpload as a parameter.
+// DownloadInput is passed to FileDownload as a parameter.
 type DownloadInput struct {
 	Bucket    string
 	ObjectKey string
 }
 
+// DetailsInput is passed to FileDetails as a parameter.
+type DetailsInput struct {
+	Bucket    string
+	ObjectKey string
+}
+
+// DetailsResponse is returned by FileDetails.
+type DetailsResponse struct {
+	ContentType   string
+	ContentLength string
+	AcceptRanges  string
+	Date          string
+	Etag          string
+	LastModified  string
+	Server        string
+	AmzID2        string
+	AmzRequestID  string
+	AmzMeta       map[string]string
+	ExtraHeaders  map[string]string
+}
+
 // UploadInput is passed to FileUpload as a parameter.
 type UploadInput struct {
 	// essential fields
@@ -422,6 +443,78 @@ func (s3 *S3) FileDelete(u DeleteInput) error {
 	return nil
 }
 
+func (s3 *S3) FileDetails(u DetailsInput) (DetailsResponse, error) {
+	req, err := http.NewRequest(
+		http.MethodHead, s3.getURL(u.Bucket, u.ObjectKey), nil,
+	)
+	if err != nil {
+		return DetailsResponse{}, err
+	}
+
+	if err := s3.signRequest(req); err != nil {
+		return DetailsResponse{}, err
+	}
+
+	res, err := s3.getClient().Do(req)
+	if err != nil {
+		return DetailsResponse{}, err
+	}
+
+	if res.StatusCode != 200 {
+		return DetailsResponse{}, fmt.Errorf("status code: %s", res.Status)
+	}
+
+	var out DetailsResponse
+	for k, v := range res.Header {
+		lk := strings.ToLower(k)
+
+		switch lk {
+		case "content-type":
+			out.ContentType = getFirstString(v)
+		case "content-length":
+			out.ContentLength = getFirstString(v)
+		case "accept-ranges":
+			out.AcceptRanges = getFirstString(v)
+		case "date":
+			out.Date = getFirstString(v)
+		case "etag":
+			out.Etag = getFirstString(v)
+		case "last-modified":
+			out.LastModified = getFirstString(v)
+		case "server":
+			out.Server = getFirstString(v)
+		case "x-amz-id-2":
+			out.AmzID2 = getFirstString(v)
+		case "x-amz-request-id":
+			out.AmzRequestID = getFirstString(v)
+		default:
+			if strings.HasPrefix(lk, AMZMetaPrefix) {
+				if out.AmzMeta == nil {
+					out.AmzMeta = map[string]string{}
+				}
+
+				out.AmzMeta[k] = getFirstString(v)
+			} else {
+				if out.ExtraHeaders == nil {
+					out.ExtraHeaders = map[string]string{}
+				}
+
+				out.ExtraHeaders[k] = getFirstString(v)
+			}
+		}
+	}
+
+	return out, nil
+}
+
+func getFirstString(s []string) string {
+	if len(s) > 0 {
+		return s[0]
+	}
+
+	return ""
+}
+
 // if object matches reserved string, no need to encode them
 var reservedObjectNames = regexp.MustCompile("^[a-zA-Z0-9-_.~/]+$")
 
diff --git a/simples3_test.go b/simples3_test.go
index 2b99e71..6169d5e 100644
--- a/simples3_test.go
+++ b/simples3_test.go
@@ -39,10 +39,11 @@ func TestS3_FileUpload(t *testing.T) {
 		u UploadInput
 	}
 	tests := []struct {
-		name    string
-		fields  tConfig
-		args    args
-		wantErr bool
+		name        string
+		fields      tConfig
+		args        args
+		testDetails bool
+		wantErr     bool
 	}{
 		{
 			name: "Upload test.txt",
@@ -63,6 +64,29 @@ func TestS3_FileUpload(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		{
+			name: "Upload test.txt with custom metadata",
+			fields: tConfig{
+				AccessKey: os.Getenv("AWS_S3_ACCESS_KEY"),
+				SecretKey: os.Getenv("AWS_S3_SECRET_KEY"),
+				Endpoint:  os.Getenv("AWS_S3_ENDPOINT"),
+				Region:    os.Getenv("AWS_S3_REGION"),
+			},
+			args: args{
+				UploadInput{
+					Bucket:      os.Getenv("AWS_S3_BUCKET"),
+					ObjectKey:   "test_metadata.txt",
+					ContentType: "text/plain",
+					FileName:    "test.txt",
+					Body:        testTxt,
+					CustomMetadata: map[string]string{
+						"test-metadata": "foo-bar",
+					},
+				},
+			},
+			wantErr:     false,
+			testDetails: true,
+		},
 		{
 			name: "Upload avatar.png",
 			fields: tConfig{
@@ -111,10 +135,29 @@ func TestS3_FileUpload(t *testing.T) {
 			if (err != nil) != tt.wantErr {
 				t.Errorf("S3.FileUpload() error = %v, wantErr %v", err, tt.wantErr)
 			}
+
+			// reset file, to reuse in further tests.
+			tt.args.u.Body.Seek(0, 0)
+
 			// check for empty response
 			if (resp == UploadResponse{}) {
 				t.Errorf("S3.FileUpload() returned empty response, %v", resp)
 			}
+
+			if tt.testDetails {
+				dResp, err := s3.FileDetails(DetailsInput{
+					Bucket:    tt.args.u.Bucket,
+					ObjectKey: tt.args.u.ObjectKey,
+				})
+
+				if (err != nil) != tt.wantErr {
+					t.Errorf("S3.FileUpload() error = %v, wantErr %v", err, tt.wantErr)
+				}
+
+				if len(dResp.AmzMeta) != 1 {
+					t.Errorf("S3.FileDetails() returned incorrect metadata, got: %v", dResp.AmzMeta)
+				}
+			}
 		})
 	}
 }