Take up double the memory when encode File.

[iWECon]

Describe the bug

It seems to take up double the memory when use try clientRequest.content.encode(Encodable.self, as: .formData).

In addition,
when the request fails, the memory will not be released normally (still taking up double the memory).
After the request is successful, the memory will be released normally.

import Vapor

struct SendFile {
    private static func generateVideoFile(_ filePath: String) throws -> File {
        let videoFileURL = URL(fileURLWithPath: filePath)
        var videoData = try Data(contentsOf: videoFileURL)
        return File(data: ByteBuffer(data: videoData), filename: (filePath as NSString).lastPathComponent)
    }
    
    struct SendFile: Codable {
        let file: File
        let userID: String
    }

    static func sendVideo(_ filePath: String, to userID: String, app: Application) async throws {
        let file = try generateVideoFile(filePath)
        
        let sendFile = SendFile(file: file, userID: userID)
        
        let response = try await app.client.post("URI") { clientRequest in
            try clientRequest.content.encode(sendFile, as: .formData)
        }
        // ...
    }
}

Environment

• Vapor 4
• Ubuntu 20.04

[MahdiBM]

Have you tried to test the memory footage in release mode too, or just in debug mode?
The form-data encoder has a known issue of taking up too much resources in debug builds, unlike in release builds where it performs just like it should.

[iWECon]

Have you tried to test the memory footage in release mode too, or just in debug mode?
The form-data encoder has a known issue of taking up too much resources in debug builds, unlike in release builds where it performs just like it should.

😂 I found this problem in the release mode.

[iWECon]

I found a temporary solution:

public struct VideoPayload: Codable, Content {
    var video: File? // << important use Optional<File>
    var thumbnail: File?  // << important use Optional<File>
    public init(video: File, thumbnail: File) {
        self.video = video
        self.thumbnail = thumbnail
    }
    
    mutating public func clear() {
        video = nil
        thumbnail = nil
    }
}

var payload = VideoPayload(
    video: File(
        data: ByteBuffer(data: try Data(contentsOf: URL(fileURLWithPath: video.videoPath))),
        filename: (video.videoPath as NSString).lastPathComponent
    ),
    thumbnail: File(
        data: ByteBuffer(data: try Data(contentsOf: URL(fileURLWithPath: thumbPath))),
        filename: (thumbPath as NSString).lastPathComponent
    )
)

let response = try await app.client.post(uri) { cr in
    // &payload, without copy data
    try cr.content.encode(&payload, as: .formData)
    
    // clear data in memory << ⚠️ see here, clear File after encoded
    payload.clear()
}