From cf141359eed7931cfb40dbb77f50e54702b98fe5 Mon Sep 17 00:00:00 2001
From: rudyfremont <114568549+rudyfremont@users.noreply.github.com>
Date: Mon, 20 Mar 2023 18:23:53 +0100
Subject: [PATCH] fix(Multipart): Create InputStream only when the body is
 filled (#23)

---
 .../MultipartForm/MultipartFormData.swift     | 32 ++++++++++++-------
 .../MultipartFormDataEncoder.swift            |  2 +-
 .../MultipartFormDataEncoderTests.swift       | 14 ++++++++
 3 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/Sources/SimpleHTTP/MultipartForm/MultipartFormData.swift b/Sources/SimpleHTTP/MultipartForm/MultipartFormData.swift
index 780b725..3fe7e6b 100644
--- a/Sources/SimpleHTTP/MultipartForm/MultipartFormData.swift
+++ b/Sources/SimpleHTTP/MultipartForm/MultipartFormData.swift
@@ -48,15 +48,30 @@ enum Boundary {
 
 struct BodyPart {
     let headers: [Header]
-    let stream: InputStream
     let length: Int
+    let stream: () throws -> InputStream
+
     var hasInitialBoundary = false
     var hasFinalBoundary = false
 
-    init(headers: [Header], stream: InputStream, length: Int) {
+    private init(headers: [Header], stream: @escaping () throws -> InputStream, length: Int) {
         self.headers = headers
-        self.stream = stream
         self.length = length
+        self.stream = stream
+    }
+
+    init(headers: [Header], url: URL, length: Int) {
+        let stream: () throws -> InputStream = {
+            guard let stream = InputStream(url: url) else {
+                throw MultipartFormData.Error.inputStreamCreationFailed(url)
+            }
+            return stream
+        }
+        self.init(headers: headers, stream: stream, length: length)
+    }
+
+    init(headers: [Header], data: Data) {
+        self.init(headers: headers, stream: { InputStream(data: data) }, length: data.count)
     }
 }
 
@@ -126,12 +141,7 @@ public struct MultipartFormData {
         }
 
         let length = fileSize.intValue
-
-        guard let stream = InputStream(url: url) else {
-            throw MultipartFormData.Error.inputStreamCreationFailed(url)
-        }
-
-        bodyParts.append(BodyPart(headers: headers, stream: stream, length: length))
+        bodyParts.append(BodyPart(headers: headers, url: url, length: length))
     }
 
     /// Creates a body part from the data and add it to the instance.
@@ -150,10 +160,8 @@ public struct MultipartFormData {
     ///   - mimeType: MIME type associated to the data in the `Content-Type` HTTPHeader.
     public mutating func add(data: Data, name: String, fileName: String? = nil, mimeType: String? = nil) {
         let headers = defineBodyPartHeader(name: name, fileName: fileName, mimeType: mimeType)
-        let stream = InputStream(data: data)
-        let length = data.count
 
-        bodyParts.append(BodyPart(headers: headers, stream: stream, length: length))
+        bodyParts.append(BodyPart(headers: headers, data: data))
     }
 
     private func defineBodyPartHeader(name: String, fileName: String?, mimeType: String?) -> [Header] {
diff --git a/Sources/SimpleHTTP/MultipartForm/MultipartFormDataEncoder.swift b/Sources/SimpleHTTP/MultipartForm/MultipartFormDataEncoder.swift
index d74378c..67bd540 100644
--- a/Sources/SimpleHTTP/MultipartForm/MultipartFormDataEncoder.swift
+++ b/Sources/SimpleHTTP/MultipartForm/MultipartFormDataEncoder.swift
@@ -46,7 +46,7 @@ struct MultipartFormDataEncoder {
         }
 
         encoded.append(try encodeBodyPart(headers: bodyPart.headers))
-        encoded.append(try encodeBodyPart(stream: bodyPart.stream, length: bodyPart.length))
+        encoded.append(try encodeBodyPart(stream: bodyPart.stream(), length: bodyPart.length))
 
         if bodyPart.hasFinalBoundary {
             encoded.append(Boundary.data(for: .final, boundary: boundary))
diff --git a/Tests/SimpleHTTPTests/MultipartForm/MultipartFormDataEncoderTests.swift b/Tests/SimpleHTTPTests/MultipartForm/MultipartFormDataEncoderTests.swift
index 2f37913..ba10610 100644
--- a/Tests/SimpleHTTPTests/MultipartForm/MultipartFormDataEncoderTests.swift
+++ b/Tests/SimpleHTTPTests/MultipartForm/MultipartFormDataEncoderTests.swift
@@ -158,4 +158,18 @@ class MultipartFormDataEncoderTests: XCTestCase {
         XCTAssertEqual(encodedData, expectedData)
     }
 
+    func test_encode_encoreMultiPartFormDataTwice_notThrow() throws {
+        let boundary = "boundary"
+        var multipart = MultipartFormData(boundary: boundary)
+
+        let data = "I'm pjechris, Nice to meet you"
+        let name1 = "data"
+        multipart.add(data: Data(data.utf8), name: name1)
+
+        var encoder = MultipartFormDataEncoder(body: multipart)
+        _ = try encoder.encode()
+
+        XCTAssertNoThrow(_ = try encoder.encode())
+    }
+
 }