A middleware for GraphQL-Go to allow file upload and field data using multipart/form-data in mutations
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README.md Initialize project Jan 6, 2019
middleware.go Added real MIME type guessing Jan 8, 2019
scalar.go Initialize project Jan 6, 2019




This library exposes a middleware for the GraphQL-Go project in order to expose a new Upload scalar type and allow you to send multipart/form-data POST requests containing files and fields data.


$ dep ensure --add github.com/eko/graphql-go-upload

Add the middleware handler in your GraphQL project

Once the dependency is installed, simply update your GraphQL project code in order to add this middleware:

import (

// ...

h := handler.GraphQL{
    Schema: graphql.MustParseSchema(schema.String(), root, graphql.MaxParallelism(maxParallelism), graphql.MaxDepth(maxDepth)),
    Handler: handler.NewHandler(conf, &m),

mux := mux.NewRouter()
mux.Handle("/graphql", upload.Handler(h)) // Add the middleware here (wrap the original handler)

s := &http.Server{
    Addr:    ":8000",
    Handler: mux,

You're ready to use the new middleware!

Use the new Upload scalar type

In order to use the new Upload scalar type, you have to declare it in your GraphQL schema and use it in your mutations, this way:

scalar Upload

type Mutation {
    myUploadMutation(file: Upload!, title: String!): Boolean

Usage on client side

On a client point of view, requests have to be formed this way:

$ curl http://localhost:8000/graphql \
  -F operations='{ "query": "mutation DoUpload($file: Upload!, $title: String!) { upload(file: $file, title: $title) }", "variables": { "file": null, "title": null } }' \
  -F map='{ "file": ["variables.file"], "title": ["variables.title"] }' \
  -F file=@myfile.txt \
  -F title="My content title"