From d2e7de229b2700f8163920c5b8bd8636cc02a808 Mon Sep 17 00:00:00 2001
From: Tim Leguijt <info@leguijtict.nl>
Date: Wed, 22 Jan 2025 14:50:04 +0100
Subject: [PATCH] set Content-Type correctly for javascript and css files (#12)

---
 .../unreleased/Added-20250121-150950.yaml     |  3 +++
 cmd/main.go                                   |  2 +-
 internal/provider_azure.go                    |  2 +-
 internal/provider_gcp.go                      |  7 +++++-
 internal/provider_s3.go                       |  2 +-
 internal/utils.go                             | 23 +++++++++++++++++--
 6 files changed, 33 insertions(+), 6 deletions(-)
 create mode 100644 .changes/unreleased/Added-20250121-150950.yaml

diff --git a/.changes/unreleased/Added-20250121-150950.yaml b/.changes/unreleased/Added-20250121-150950.yaml
new file mode 100644
index 0000000..01a76c1
--- /dev/null
+++ b/.changes/unreleased/Added-20250121-150950.yaml
@@ -0,0 +1,3 @@
+kind: Added
+body: 'GCP: Detection of JS and CSS filetype and set ContentType'
+time: 2025-01-21T15:09:50.953801+01:00
diff --git a/cmd/main.go b/cmd/main.go
index dd5c60e..840ed7a 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -78,7 +78,7 @@ var syncCmd = &cobra.Command{
 		fmt.Println("Directory synchronized successfully; creating lock file")
 
 		// Create the lockfile (empty file)
-		err = client.UploadFile(ctx, strings.NewReader(""), filepath.Join(remoteDir, lockFile))
+		err = client.UploadFile(ctx, strings.NewReader(""), filepath.Join(remoteDir, lockFile), "")
 		if err != nil {
 			log.Fatalf("failed to create lock file: %v", err)
 		}
diff --git a/internal/provider_azure.go b/internal/provider_azure.go
index 2b507bf..e864ba4 100644
--- a/internal/provider_azure.go
+++ b/internal/provider_azure.go
@@ -38,7 +38,7 @@ func NewAzureBlobClient(ctx context.Context, bucket string) (*AzureBlobClient, e
 	return &AzureBlobClient{client: client, container: container}, nil
 }
 
-func (c *AzureBlobClient) UploadFile(ctx context.Context, file io.Reader, remotePath string) error {
+func (c *AzureBlobClient) UploadFile(ctx context.Context, file io.Reader, remotePath string, contentType string) error {
 	var tempFile *os.File
 	var err error
 
diff --git a/internal/provider_gcp.go b/internal/provider_gcp.go
index c8e7587..cdb27d6 100644
--- a/internal/provider_gcp.go
+++ b/internal/provider_gcp.go
@@ -22,11 +22,16 @@ func NewGCSClient(ctx context.Context, bucket string) (*GCSClient, error) {
 }
 
 // UploadFile to GCS
-func (c *GCSClient) UploadFile(ctx context.Context, file io.Reader, remotePath string) error {
+func (c *GCSClient) UploadFile(ctx context.Context, file io.Reader, remotePath string, contentType string) error {
 	bucket := c.client.Bucket(c.bucket)
 	obj := bucket.Object(remotePath)
 
 	writer := obj.NewWriter(ctx)
+
+	if contentType != "" {
+		writer.ContentType = contentType
+	}
+
 	defer writer.Close()
 
 	_, err := io.Copy(writer, file)
diff --git a/internal/provider_s3.go b/internal/provider_s3.go
index 5bc2f00..77e0276 100644
--- a/internal/provider_s3.go
+++ b/internal/provider_s3.go
@@ -26,7 +26,7 @@ func NewS3Client(ctx context.Context, bucket string) (*S3Client, error) {
 }
 
 // UploadFile to S3
-func (c *S3Client) UploadFile(ctx context.Context, file io.Reader, remotePath string) error {
+func (c *S3Client) UploadFile(ctx context.Context, file io.Reader, remotePath string, contentType string) error {
 	_, err := c.client.PutObject(ctx, &s3.PutObjectInput{
 		Bucket: aws.String(c.bucket),
 		Key:    aws.String(remotePath),
diff --git a/internal/utils.go b/internal/utils.go
index 606b3aa..950667a 100644
--- a/internal/utils.go
+++ b/internal/utils.go
@@ -10,7 +10,7 @@ import (
 )
 
 type StorageClient interface {
-	UploadFile(ctx context.Context, file io.Reader, remotePath string) error
+	UploadFile(ctx context.Context, file io.Reader, remotePath string, contentType string) error
 	FileExists(ctx context.Context, remotePath string) (bool, error)
 }
 
@@ -45,7 +45,12 @@ func SyncDirectory(ctx context.Context, client StorageClient, localDir, remoteDi
 					return
 				}
 				defer file.Close()
-				if err := client.UploadFile(ctx, file, remotePath); err != nil {
+
+				// Get the content type based on file extension.
+				// We can't rely on auto-detection of mimetypes because
+				// of security implications. See https://stackoverflow.com/questions/70695214/net-http-does-detectcontenttype-support-javascript
+				contentType := GetContentType(path)
+				if err := client.UploadFile(ctx, file, remotePath, contentType); err != nil {
 					errCh <- err
 				} else {
 					fmt.Printf("Uploaded %s to %s\n", path, remotePath)
@@ -69,3 +74,17 @@ func SyncDirectory(ctx context.Context, client StorageClient, localDir, remoteDi
 	}
 	return nil
 }
+
+func GetContentType(file string) string {
+	ext := filepath.Ext(file)
+	switch ext {
+	case ".htm", ".html":
+		return "text/html; charset=UTF-8"
+	case ".css":
+		return "text/css; charset=UTF-8"
+	case ".js":
+		return "application/javascript; charset=UTF-8"
+	}
+
+	return ""
+}