How to Use Multi-Related Stream to Upload DICOM Files Implementing Multi-File Upload with CURL Scripts or .NET Core Applications During STOW-RS development, to test RESTful API interfaces, we created a CURL script that uploads multiple DICOM files.
It’s important to note that RESTful interfaces require uploads to be in multipart/related format with Content-Type: multipart/related;boundary=DICOM_BOUNDARY;type=application/dicom.
CURL Script Implementation #!/bin/bash # Check parameters if [ $# -eq 0 ]; then echo "Usage: $0 <dicom_directory>" echo "Example: $0 ~/amprData" exit 1 fi DICOM_DIR="$1" # Check if directory exists if [ ! -d "$DICOM_DIR" ]; then echo "Error: Directory '$DICOM_DIR' does not exist" exit 1 fi BOUNDARY="DICOM_BOUNDARY" TEMP_FILE="multipart_request_largdata.tmp" # Check for DICOM files DICOM_FILES=($(find "$DICOM_DIR" -type f -name "*.dcm")) if [ ${#DICOM_FILES[@]} -eq 0 ]; then echo "Warning: No DICOM files found in '$DICOM_DIR'" exit 0 fi echo "Found ${#DICOM_FILES[@]} DICOM files" # 1. Initialize file (without JSON part) > "$TEMP_FILE" # 2. Loop through all DICOM files (first file doesn't need prefix separator) for i in "${!DICOM_FILES[@]}"; do dicom_file="${DICOM_FILES[$i]}" # Add prefix separator for all files except the first if [ $i -gt 0 ]; then printf -- "\r\n--%s\r\n" "$BOUNDARY" >> "$TEMP_FILE" else # First file needs starting separator printf -- "--%s\r\n" "$BOUNDARY" >> "$TEMP_FILE" fi printf -- "Content-Type: application/dicom\r\n\r\n" >> "$TEMP_FILE" # Append DICOM file content cat "$dicom_file" >> "$TEMP_FILE" echo "Added file: $(basename "$dicom_file")" done # 3. Write ending separator for request body printf -- "\r\n--%s--\r\n" "$BOUNDARY" >> "$TEMP_FILE" # 4. Calculate file size CONTENT_LENGTH=$(wc -c < "$TEMP_FILE" | tr -d ' ') echo "Total content length: $CONTENT_LENGTH bytes" # 5. Send request curl -X POST http://localhost:9000/stow-rs/v1/studies \ -H "Content-Type: multipart/related; boundary=$BOUNDARY; type=application/dicom" \ -H "Accept: application/json" \ -H "x-tenant: 1234567890" \ -H "Content-Length: $CONTENT_LENGTH" \ --data-binary @"$TEMP_FILE" # 6. Clean up temporary file rm "$TEMP_FILE" echo "Upload completed" .NET Core Implementation using System.Text; namespace MakeMultirelate { public class ConstructPostRequest : IDisposable { private const string Boundary = "DICOM_BOUNDARY"; private readonly HttpClient _httpClient = new(); public async Task SendDicomFilesAsync(List<string> dicomFilePaths, string url, string tenantId) { // Estimate memory stream size for performance optimization long estimatedSize = 0; foreach (var filePath in dicomFilePaths) { if (!File.Exists(filePath)) throw new FileNotFoundException($"DICOM file not found: {filePath}"); // Get file size and accumulate var fileInfo = new FileInfo(filePath); estimatedSize += fileInfo.Length; } // Add estimated size for boundaries and headers (approximately 200 bytes per file for separators and headers) estimatedSize += dicomFilePaths.Count * 200; // Add end boundary size estimatedSize += Boundary.Length + 10; // Create memory stream to build multipart content with estimated size initialization using var memoryStream = new MemoryStream((int)Math.Min(estimatedSize, int.MaxValue)); // Build multipart content foreach (var filePath in dicomFilePaths) { if (!File.Exists(filePath)) throw new FileNotFoundException($"DICOM file not found: {filePath}"); // Add separator and header var separator = Encoding.UTF8.GetBytes($"\r\n--{Boundary}\r\n"); var header = Encoding.UTF8.GetBytes("Content-Type: application/dicom\r\n\r\n"); if (memoryStream.Length == 0) { // First part doesn't need leading separator separator = Encoding.UTF8.GetBytes($"--{Boundary}\r\n"); } await memoryStream.WriteAsync(separator, 0, separator.Length); await memoryStream.WriteAsync(header, 0, header.Length); // Read and add DICOM file content var fileBytes = await File.ReadAllBytesAsync(filePath); await memoryStream.WriteAsync(fileBytes, 0, fileBytes.Length); } // Add ending separator var endBoundary = Encoding.UTF8.GetBytes($"\r\n--{Boundary}--\r\n"); await memoryStream.WriteAsync(endBoundary, 0, endBoundary.Length); // Prepare request content var content = new ByteArrayContent(memoryStream.ToArray()); content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("multipart/related"); content.Headers.ContentType.Parameters.Add( new System.Net.Http.Headers.NameValueHeaderValue("boundary", Boundary)); content.Headers.ContentType.Parameters.Add( new System.Net.Http.Headers.NameValueHeaderValue("type", "application/dicom")); // Set request headers _httpClient.DefaultRequestHeaders.Clear(); _httpClient.DefaultRequestHeaders.Add("Accept", "application/json"); _httpClient.DefaultRequestHeaders.Add("x-tenant", tenantId); // Send request var response = await _httpClient.PostAsync(url, content); // Process response var responseContent = await response.Content.ReadAsStringAsync(); Console.WriteLine($"Status Code: {response.StatusCode}"); Console.WriteLine($"Response: {responseContent}"); } // Overloaded function: Recursively find DICOM files based on directory public async Task SendDicomFilesAsync(string dicomDirectory, string url, string tenantId) { if (!Directory.Exists(dicomDirectory)) throw new DirectoryNotFoundException($"DICOM directory not found: {dicomDirectory}"); // Recursively find all files with .dcm extension var dicomFiles = Directory.GetFiles(dicomDirectory, "*.dcm", SearchOption.AllDirectories); // If no files found, throw exception if (dicomFiles.Length == 0) throw new FileNotFoundException($"No DICOM files found in directory: {dicomDirectory}"); // Call original method to send files await SendDicomFilesAsync(dicomFiles.ToList(), url, tenantId); } public void Dispose() { _httpClient.Dispose(); } } } Key Implementation Points Multipart/Related Format Content-Type must be multipart/related;boundary=DICOM_BOUNDARY;type=application/dicom Each DICOM file requires proper boundary delimiters First file needs a starting boundary, subsequent files need separator boundaries
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