Uploading files
Apollo Kotlin supports file uploads via the GraphQL multipart request specification.
First, add the following custom scalar mapping to the Apollo Gradle plugin configuration:
Kotlin
build.gradle[.kts]
1apollo {
2 service("service") {
3 mapScalarToUpload("Upload")
4 }
5}In this example, the GraphQL schema defines a custom scalar type named Upload. You can use a different name as needed for your schema.
Note: You don't need to register a type adapter for
Upload, because themapScalarToUploadmethod registers it automatically.
Now let's consider a mutation that takes an Upload as a parameter:
GraphQL
1mutation SingleUpload($file: Upload!) {
2 singleUpload(file: $file) {
3 id
4 path
5 filename
6 mimetype
7 }
8}Create an instance of Upload using one of the factory methods:
Kotlin
1// If you're on Android/JVM, you can turn a File into an upload
2val upload = File.toUpload("application/json")
3
4// On multiplatform, you can use `DefaultUpload`
5val upload = DefaultUpload.Builder()
6 .fileName("filename.txt")
7 .content { sink ->
8 okioSource.use { sink.writeAll(it) }
9 }
10 .build()And execute your mutation:
Kotlin
1val response = apolloClient.mutation(SingleUploadMutation(file = upload)).execute()