Fix for multi-variable uploads

Sources/Apollo/RequestCreator.swift

@@ -107,15 +107,15 @@ extension RequestCreator {
 
     // Make sure all fields for files are set to null, or the server won't look
     // for the files in the rest of the form data
-    let fieldsForFiles = Set(files.map { $0.fieldName })
+    let fieldsForFiles = Set(files.map { $0.fieldName }).sorted()
     var fields = requestBody(for: operation, sendOperationIdentifiers: sendOperationIdentifiers)
     var variables = fields["variables"] as? GraphQLMap ?? GraphQLMap()
     for fieldName in fieldsForFiles {
       if
         let value = variables[fieldName],
         let arrayValue = value as? [JSONEncodable] {
-        let updatedArray: [JSONEncodable?] = arrayValue.map { _ in nil }
-          variables.updateValue(updatedArray, forKey: fieldName)
+        let arrayOfNils: [JSONEncodable?] = arrayValue.map { _ in nil }
+          variables.updateValue(arrayOfNils, forKey: fieldName)
       } else {
         variables.updateValue(nil, forKey: fieldName)
       }
@@ -125,20 +125,33 @@ extension RequestCreator {
     let operationData = try serializationFormat.serialize(value: fields)
     formData.appendPart(data: operationData, name: "operations")
 
+    // If there are multiple files for the same field, make sure to include them with indexes for the field. If there are multiple files for different fields, just use the field name.
     var map = [String: [String]]()
-    if files.count == 1 {
-      let firstFile = files.first!
-      map["0"] = ["variables.\(firstFile.fieldName)"]
-    } else {
-      for (index, file) in files.enumerated() {
-        map["\(index)"] = ["variables.\(file.fieldName).\(index)"]
+    var currentIndex = 0
+
+    var sortedFiles = [GraphQLFile]()
+    for fieldName in fieldsForFiles {
+      let filesForField = files.filter { $0.fieldName == fieldName }
+      if filesForField.count == 1 {
+        let firstFile = filesForField.first!
+        map["\(currentIndex)"] = ["variables.\(firstFile.fieldName)"]
+        sortedFiles.append(firstFile)
+        currentIndex += 1
+      } else {
+        for (index, file) in filesForField.enumerated() {
+          map["\(currentIndex)"] = ["variables.\(file.fieldName).\(index)"]
+          sortedFiles.append(file)
+          currentIndex += 1
+        }
       }
     }
+
+    assert(sortedFiles.count == files.count, "Number of sorted files did not equal the number of incoming files - some field name has been left out.")
 
     let mapData = try serializationFormat.serialize(value: map)
     formData.appendPart(data: mapData, name: "map")
 
-    for (index, file) in files.enumerated() {
+    for (index, file) in sortedFiles.enumerated() {
       formData.appendPart(inputStream: try file.generateInputStream(),
                           contentLength: file.contentLength,
                           name: "\(index)",

Tests/ApolloTests/RequestCreatorTests.swift

@@ -14,8 +14,6 @@ class RequestCreatorTests: XCTestCase {
   private let customRequestCreator = TestCustomRequestCreator()
   private let apolloRequestCreator = ApolloRequestCreator()
 
-
-
   private func checkString(_ string: String,
                            includes expectedString: String,
                            file: StaticString = #file,
@@ -289,6 +287,94 @@ Bravo file content.
     }
   }
 
+  func testMultipleFilesWithMultipleFieldsWithApolloRequestCreator() throws {
+    let alphaFileURL = self.fileURLForFile(named: "a", extension: "txt")
+    let alphaFile = try GraphQLFile(fieldName: "uploads",
+                                    originalName: "a.txt",
+                                    mimeType: "text/plain",
+                                    fileURL: alphaFileURL)
+
+    let betaFileURL = self.fileURLForFile(named: "b", extension: "txt")
+    let betaFile = try GraphQLFile(fieldName: "uploads",
+                                   originalName: "b.txt",
+                                   mimeType: "text/plain",
+                                   fileURL: betaFileURL)
+
+    let charlieFileUrl = self.fileURLForFile(named: "c", extension: "txt")
+    let charlieFile = try GraphQLFile(fieldName: "secondField",
+                                      originalName: "c.txt",
+                                      mimeType: "text/plain",
+                                      fileURL: charlieFileUrl)
+
+    let data = try apolloRequestCreator.requestMultipartFormData(
+      for: HeroNameQuery(),
+      files: [alphaFile, betaFile, charlieFile],
+      sendOperationIdentifiers: false,
+      serializationFormat: JSONSerializationFormat.self,
+      manualBoundary: "TEST.BOUNDARY"
+    )
+
+    let stringToCompare = try self.string(from: data)
+
+    if JSONSerialization.dataCanBeSorted() {
+      let expectedString = """
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="operations"
+
+  {"operationName":"HeroName","query":"query HeroName($episode: Episode) {\\n  hero(episode: $episode) {\\n    __typename\\n    name\\n  }\\n}","variables":{"episode":null,\"secondField\":null,\"uploads\":null}}
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="map"
+
+  {"0":["variables.secondField"],"1":["variables.uploads.0"],"2":["variables.uploads.1"]}
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="0"; filename="c.txt"
+  Content-Type: text/plain
+
+  Charlie file content.
+
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="1"; filename="a.txt"
+  Content-Type: text/plain
+
+  Alpha file content.
+
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="2"; filename="b.txt"
+  Content-Type: text/plain
+
+  Bravo file content.
+
+  --TEST.BOUNDARY--
+  """
+      XCTAssertEqual(stringToCompare, expectedString)
+    } else {
+      // Query and operation parameters may be in weird order, so let's at least check that the files got encoded properly.
+      let endString = """
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="0"; filename="c.txt"
+  Content-Type: text/plain
+
+  Charlie file content.
+
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="1"; filename="a.txt"
+  Content-Type: text/plain
+
+  Alpha file content.
+
+  --TEST.BOUNDARY
+  Content-Disposition: form-data; name="2"; filename="b.txt"
+  Content-Type: text/plain
+
+  Bravo file content.
+
+  --TEST.BOUNDARY--
+  """
+      self.checkString(stringToCompare, includes: endString)
+    }
+  }
+
+
   func testRequestBodyWithApolloRequestCreator() {
     let query = HeroNameQuery()
     let req = apolloRequestCreator.requestBody(for: query, sendOperationIdentifiers: false)