How do I make ApolloClient use multipart/form-data when sending requests to Django GraphQL endpoint?

If you’re building a GraphQL API with Django and using ApolloClient to interact with it, you may have stumbled upon a peculiar issue: sending files to your server. By default, ApolloClient sends requests as JSON, which isn’t suitable for sending files. In this article, we’ll explore how to configure ApolloClient to use multipart/form-data when sending requests to your Django GraphQL endpoint.

Understanding the Problem

When you send a file from your ApolloClient to your Django GraphQL server, you might receive an error like ” GraphQL error: Uploads are not supported” or “TypeError: Cannot read property ‘file’ of null”. This is because ApolloClient, by default, sends requests as JSON, which can’t handle file uploads.

The solution lies in configuring ApolloClient to send requests as multipart/form-data, a format that allows sending files along with other data. But how do you do that?

Configuring ApolloClient to use multipart/form-data

The magic happens in the `ApolloClient` constructor, where you define the `link` option. You need to create a custom `link` that can handle file uploads.

import { ApolloClient, InMemoryCache } from '@apollo/client';
import { createUploadLink } from 'apollo-upload-client';

const client = new ApolloClient({
  cache: new InMemoryCache(),
  link: createUploadLink({
    uri: 'https://your-django-graphql-endpoint.com/graphql',
    headers: {
      'X-CSRFToken': getCookie('csrftoken'),
    },
    credentials: 'same-origin',
  }),
});

In the above code, we’re using the `createUploadLink` function from `apollo-upload-client` to create a custom link. This link will handle file uploads by sending requests as multipart/form-data.

What’s `createUploadLink` doing?

The `createUploadLink` function returns a link that wraps the `fetch` function. When a request is sent, it checks if the operation has a `variables` object containing a file. If it does, it sends the request as multipart/form-data, which allows the file to be sent along with other data.

Handling File Uploads in Django GraphQL

Now that ApolloClient is sending requests as multipart/form-data, you need to configure your Django GraphQL endpoint to handle these requests.

Using GraphAPI

If you’re using GraphAPI, you can use the built-in `Upload` scalar type to handle file uploads.

import graphene
from graphene_django.types import DjangoObjectType
from .models import MyModel

class MyType(DjangoObjectType):
    class Meta:
        model = MyModel

class UploadFile(graphene.Mutation):
    class Arguments:
        file = Upload(required=True)

    ok = graphene.Boolean()
    file = graphene.String()

    @staticmethod
    def mutate(root, info, file):
        # Handle the uploaded file
        # ...
        return UploadFile(ok=True, file=file)

class Mutation(graphene.ObjectType):
    upload_file = UploadFile.Field()

In the above code, we’re defining a `UploadFile` mutation that accepts a file as an argument. The `Upload` scalar type is used to specify that the `file` argument should be a file.

Using Django GraphQL API

If you’re using the Django GraphQL API, you can use the `django_graphql_api.types.Upload` type to handle file uploads.

import graphene
from django_graphql_api.types import Upload

class MyType(graphene.ObjectType):
    file = graphene.Field(Upload)

class Mutation(graphene.ObjectType):
    upload_file = graphene.Field(MyType, file=Upload())

    def resolve_upload_file(self, info, file):
        # Handle the uploaded file
        # ...
        return MyType(file=file)

In the above code, we’re defining a `MyType` type that has a `file` field of type `Upload`. The `upload_file` mutation accepts a file as an argument and returns an instance of `MyType` with the uploaded file.

Common Issues and Solutions

When working with file uploads, you might encounter some common issues.

Issue: File not being sent

Solution: Make sure you’re sending the file as a `File` object, not as a string or buffer.

const fileInput = document.getElementById('fileInput');
const file = fileInput.files[0];

const variables = {
  file,
};

Issue: File being sent as binary data

Solution: Use the `FormData` API to send the file as a form field.

const fileInput = document.getElementById('fileInput');
const file = fileInput.files[0];

const formData = new FormData();
formData.append('file', file);

const variables = {
  file: formData,
};

Conclusion

In this article, we’ve explored how to configure ApolloClient to use multipart/form-data when sending requests to a Django GraphQL endpoint. We’ve also covered how to handle file uploads in Django GraphQL using GraphAPI and Django GraphQL API.

By following these steps, you should be able to send files from your ApolloClient to your Django GraphQL server. Remember to handle file uploads carefully, as they can be a security risk if not implemented properly.

Keyword	Explanation
ApolloClient	A popular GraphQL client for JavaScript
Django GraphQL	A Python framework for building GraphQL APIs with Django
multipart/form-data	A MIME type that allows sending files along with other data
GraphAPI	A Python library for building GraphQL APIs
Django GraphQL API	A Python library for building GraphQL APIs with Django

Remember to always follow best practices when handling file uploads, and happy coding!

• Check out the official ApolloClient documentation for more information on configuring the client.
• Explore GraphAPI and Django GraphQL API for more features and examples.
• Learn about security best practices for handling file uploads.

Frequently Asked Question

Stuck with sending multipart/form-data requests to your Django GraphQL endpoint using ApolloClient? Worry not, friend! We’ve got you covered with these FAQs.