[GraphQL] Add create direct upload mutation

app/graphql/mutations/base_mutation.rb

@@ -1,4 +1,4 @@
 module Mutations
-  class BaseMutation < GraphQL::Schema::Mutation
+  class BaseMutation < GraphQL::Schema::RelayClassicMutation
   end
 end

app/graphql/mutations/create_direct_upload.rb

@@ -0,0 +1,41 @@
+module Mutations
+  class CreateDirectUpload < Mutations::BaseMutation
+    description "File information required to prepare a direct upload"
+
+    argument :dossier_id, ID, "Dossier ID", required: true, loads: Types::DossierType
+    argument :filename, String, "Original file name", required: true
+    argument :byte_size, Int, "File size (bytes)", required: true
+    argument :checksum, String, "MD5 file checksum as base64", required: true
+    argument :content_type, String, "File content type", required: true
+
+    class DirectUpload < Types::BaseObject
+      description "Represents direct upload credentials"
+
+      field :url, String, "Upload URL", null: false
+      field :headers, String, "HTTP request headers (JSON-encoded)", null: false
+      field :blob_id, ID, "Created blob record ID", null: false
+      field :signed_blob_id, ID, "Created blob record signed ID", null: false
+    end
+
+    field :direct_upload, DirectUpload, null: false
+
+    def resolve(filename:, byte_size:, checksum:, content_type:, dossier:)
+      blob = ActiveStorage::Blob.create_before_direct_upload!(
+        filename: filename,
+        byte_size: byte_size,
+        checksum: checksum,
+        content_type: content_type
+      )
+
+      {
+        direct_upload: {
+          url: blob.service_url_for_direct_upload,
+          # NOTE: we pass headers as JSON since they have no schema
+          headers: blob.service_headers_for_direct_upload.to_json,
+          blob_id: blob.id,
+          signed_blob_id: blob.signed_id
+        }
+      }
+    end
+  end
+end

app/graphql/schema.graphql

@@ -40,6 +40,52 @@ GeoJSON coordinates
 """
 scalar Coordinates
 
+"""
+Autogenerated input type of CreateDirectUpload
+"""
+input CreateDirectUploadInput {
+  """
+  File size (bytes)
+  """
+  byteSize: Int!
+
+  """
+  MD5 file checksum as base64
+  """
+  checksum: String!
+
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+
+  """
+  File content type
+  """
+  contentType: String!
+
+  """
+  Dossier ID
+  """
+  dossierId: ID!
+
+  """
+  Original file name
+  """
+  filename: String!
+}
+
+"""
+Autogenerated return type of CreateDirectUpload
+"""
+type CreateDirectUploadPayload {
+  """
+  A unique identifier for the client performing the mutation.
+  """
+  clientMutationId: String
+  directUpload: DirectUpload!
+}
+
 type DateChamp implements Champ {
   id: ID!
   label: String!
@@ -131,6 +177,31 @@ enum DemarcheState {
   publiee
 }
 
+"""
+Represents direct upload credentials
+"""
+type DirectUpload {
+  """
+  Created blob record ID
+  """
+  blobId: ID!
+
+  """
+  HTTP request headers (JSON-encoded)
+  """
+  headers: String!
+
+  """
+  Created blob record signed ID
+  """
+  signedBlobId: ID!
+
+  """
+  Upload URL
+  """
+  url: String!
+}
+
 """
 Un dossier
 """
@@ -324,6 +395,10 @@ type MultipleDropDownListChamp implements Champ {
 }
 
 type Mutation {
+  """
+  File information required to prepare a direct upload
+  """
+  createDirectUpload(input: CreateDirectUploadInput!): CreateDirectUploadPayload
 }
 
 """

app/graphql/types/mutation_type.rb

@@ -1,4 +1,5 @@
 module Types
   class MutationType < Types::BaseObject
+    field :create_direct_upload, mutation: Mutations::CreateDirectUpload
   end
 end

spec/controllers/api/v2/graphql_controller_spec.rb

@@ -166,6 +166,39 @@ describe API::V2::GraphqlController do
         expect(gql_data[:dossier][:champs][0][:id]).to eq(dossier.champs[0].type_de_champ.to_typed_id)
       end
     end
+
+    context "mutations" do
+      context 'createDirectUpload' do
+        let(:query) do
+          "mutation {
+            createDirectUpload(input: {
+              dossierId: \"#{dossier.to_typed_id}\",
+              filename: \"hello.png\",
+              byteSize: 1234,
+              checksum: \"qwerty1234\",
+              contentType: \"image/png\"
+            }) {
+              directUpload {
+                url
+                headers
+                blobId
+                signedBlobId
+              }
+            }
+          }"
+        end
+
+        it "should initiate a direct upload" do
+          expect(gql_errors).to eq(nil)
+
+          data = gql_data[:createDirectUpload][:directUpload]
+          expect(data[:url]).not_to be_nil
+          expect(data[:headers]).not_to be_nil
+          expect(data[:blobId]).not_to be_nil
+          expect(data[:signedBlobId]).not_to be_nil
+        end
+      end
+    end
   end
 
   context "when not authenticated" do