npm package: @nexusapp/apollo-upload-client
Description: A terminating Apollo Link for Apollo Client that allows FileList, File, Blob or ReactNativeFile instances within query or mutation variables and sends GraphQL multipart requests.
Author: Jayden Seric
Latest version: 14.1.3-patch2

![Apollo upload logo](https://cdn.jsdelivr.net/gh/jaydenseric/apollo-upload-client@1.0.0/apollo-upload-logo.svg)

# apollo-upload-client

[![npm version](https://badgen.net/npm/v/apollo-upload-client)](https://npm.im/apollo-upload-client) [![CI status](https://github.com/jaydenseric/apollo-upload-client/workflows/CI/badge.svg)](https://github.com/jaydenseric/apollo-upload-client/actions)

A [terminating Apollo Link](https://apollographql.com/docs/link/overview/#terminating-links) for [Apollo Client](https://apollographql.com/docs/react) that allows [`FileList`](https://developer.mozilla.org/en-US/docs/Web/API/FileList), [`File`](https://developer.mozilla.org/en-US/docs/Web/API/File), [`Blob`](https://developer.mozilla.org/en-US/docs/Web/API/Blob) or [`ReactNativeFile`](#class-reactnativefile) instances within query or mutation variables and sends [GraphQL multipart requests](https://github.com/jaydenseric/graphql-multipart-request-spec).

## Setup

Install with [npm](https://npmjs.com/get-npm):

```shell
npm install apollo-upload-client
```

Remove any `uri`, `credentials`, or `headers` options from the [`ApolloClient` constructor](https://apollographql.com/docs/react/api/core/ApolloClient/#the-apolloclient-constructor).

[Apollo Client](https://apollographql.com/docs/react) can only have 1 [terminating Apollo Link](https://apollographql.com/docs/link/overview/#terminating-links) that sends the GraphQL requests; if one such as [`HttpLink`](https://apollographql.com/docs/link/links/http) is already setup, remove it.

Initialize the client with a [terminating Apollo Link](https://apollographql.com/docs/link/overview/#terminating-links) using [`createUploadLink`](#function-createuploadlink).

Also ensure the GraphQL server implements the [GraphQL multipart request spec](https://github.com/jaydenseric/graphql-multipart-request-spec) and that uploads are handled correctly in resolvers.

## Usage

Use [`FileList`](https://developer.mozilla.org/en-US/docs/Web/API/FileList), [`File`](https://developer.mozilla.org/en-US/docs/Web/API/File), [`Blob`](https://developer.mozilla.org/en-US/docs/Web/API/Blob) or [`ReactNativeFile`](#class-reactnativefile) instances anywhere within query or mutation variables to send a [GraphQL multipart request](https://github.com/jaydenseric/graphql-multipart-request-spec).

See also the [example API and client](https://github.com/jaydenseric/apollo-upload-examples).

### [`FileList`](https://developer.mozilla.org/en-US/docs/Web/API/FileList)

```jsx
import { gql, useMutation } from '@apollo/client';

const MUTATION = gql`
  mutation ($files: [Upload!]!) {
    uploadFiles(files: $files) {
      success
    }
  }
`;

function UploadFiles() {
  const [mutate] = useMutation(MUTATION);

  function onChange({ target: { validity, files } }) {
    if (validity.valid) mutate({ variables: { files } });
  }

  return <input type="file" multiple required onChange={onChange} />;
}
```

### [`File`](https://developer.mozilla.org/en-US/docs/Web/API/File)

```jsx
import { gql, useMutation } from '@apollo/client';

const MUTATION = gql`
  mutation ($file: Upload!) {
    uploadFile(file: $file) {
      success
    }
  }
`;

function UploadFile() {
  const [mutate] = useMutation(MUTATION);

  function onChange({
    target: {
      validity,
      files: [file],
    },
  }) {
    if (validity.valid) mutate({ variables: { file } });
  }

  return <input type="file" required onChange={onChange} />;
}
```

### [`Blob`](https://developer.mozilla.org/en-US/docs/Web/API/Blob)

```jsx
import { gql, useMutation } from '@apollo/client';

const MUTATION = gql`
  mutation ($file: Upload!) {
    uploadFile(file: $file) {
      success
    }
  }
`;

function UploadFile() {
  const [mutate] = useMutation(MUTATION);

  function onChange({ target: { validity, value } }) {
    if (validity.valid) {
      const file = new Blob([value], { type: 'text/plain' });

      // Optional, defaults to `blob`.
      file.name = 'text.txt';

      mutate({ variables: { file } });
    }
  }

  return <input type="text" required onChange={onChange} />;
}
```

## Support

- Node.js `^10.17.0 || ^12.0.0 || >= 13.7.0`
- Browsers [`> 0.5%, not OperaMini all, not dead`](https://browserl.ist/?q=%3E+0.5%25%2C+not+OperaMini+all%2C+not+dead)
- React Native

Consider polyfilling:

- [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)
- [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API)
- [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData)

## API

### Table of contents

- [function createUploadLink](#function-createuploadlink)
- [function formDataAppendFile](#function-formdataappendfile)
- [function isExtractableFile](#function-isextractablefile)
- [type ExtractableFileMatcher](#type-extractablefilematcher)
- [type FetchOptions](#type-fetchoptions)
- [type FormDataFileAppender](#type-formdatafileappender)
- [type ReactNativeFileSubstitute](#type-reactnativefilesubstitute)

### function createUploadLink

Creates a [terminating Apollo Link](https://apollographql.com/docs/link/overview/#terminating-links) capable of file uploads.

The link matches and extracts files in the GraphQL operation. If there are files it uses a [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) instance as the [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch) `options.body` to make a [GraphQL multipart request](https://github.com/jaydenseric/graphql-multipart-request-spec), otherwise it sends a regular POST request.

Some of the options are similar to the [`createHttpLink` options](https://apollographql.com/docs/link/links/http/#options).

| Parameter | Type | Description |
| :-- | :-- | :-- |
| `options` | object | Options. |
| `options.uri` | string? = `/graphql` | GraphQL endpoint URI. |
| `options.useGETForQueries` | boolean? | Should GET be used to fetch queries, if there are no files to upload. |
| `options.isExtractableFile` | [ExtractableFileMatcher](#type-extractablefilematcher)? = [isExtractableFile](#function-isextractablefile) | Customizes how files are matched in the GraphQL operation for extraction. |
| `options.FormData` | class? | [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) implementation to use, defaulting to the [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) global. |
| `options.formDataAppendFile` | [FormDataFileAppender](#type-formdatafileappender)? = [formDataAppendFile](#function-formdataappendfile) | Customizes how extracted files are appended to the [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) instance. |
| `options.fetch` | Function? | [`fetch`](https://fetch.spec.whatwg.org) implementation to use, defaulting to the [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch) global. |
| `options.fetchOptions` | [FetchOptions](#type-fetchoptions)? | [`fetch` options](#type-fetchoptions); overridden by upload requirements. |
| `options.credentials` | string? | Overrides `options.fetchOptions.credentials`. |
| `options.headers` | object? | Merges with and overrides `options.fetchOptions.headers`. |
| `options.includeExtensions` | boolean? = `false` | Toggles sending `extensions` fields to the GraphQL server. |

**Returns:** ApolloLink — A [terminating Apollo Link](https://apollographql.com/docs/link/overview/#terminating-links) capable of file uploads.

#### See

- [GraphQL multipart request spec](https://github.com/jaydenseric/graphql-multipart-request-spec).
- [`apollo-link` on GitHub](https://github.com/apollographql/apollo-link).

#### Examples

_Ways to `import`._

> ```js
> import { createUploadLink } from 'apollo-upload-client';
> ```
>
> ```js
> import createUploadLink from 'apollo-upload-client/public/createUploadLink.js';
> ```

_Ways to `require`._

> ```js
> const { createUploadLink } = require('apollo-upload-client');
> ```
>
> ```js
> const createUploadLink = require('apollo-upload-client/public/createUploadLink');
> ```

_A basic Apollo Client setup._

> ```js
> import { ApolloClient, InMemoryCache } from '@apollo/client';
> import { createUploadLink } from 'apollo-upload-client';
>
> const client = new ApolloClient({
>   cache: new InMemoryCache(),
>   link: createUploadLink(),
> });
> ```

---

### function formDataAppendFile

The default implementation for [`createUploadLink`](#function-createuploadlink) `options.formDataAppendFile` that uses the standard [`FormData.append`](https://developer.mozilla.org/en-US/docs/Web/API/FormData/append) method.

**Type:** [FormDataFileAppender](#type-formdatafileappender)

| Parameter | Type | Description |
| :-- | :-- | :-- |
| `formData` | FormData | [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) instance to append the specified file to. |
| `fieldName` | string | Field name for the file. |
| `file` | \* | File to append. |

#### Examples

_Ways to `import`._

> ```js
> import { formDataAppendFile } from 'apollo-upload-client';
> ```
>
> ```js
> import formDataAppendFile from 'apollo-upload-client/public/formDataAppendFile.js';
> ```

_Ways to `require`._

> ```js
> const { formDataAppendFile } = require('apollo-upload-client');
> ```
>
> ```js
> const formDataAppendFile = require('apollo-upload-client/public/formDataAppendFile');
> ```

---

### function isExtractableFile

The default implementation for [`createUploadLink`](#function-createuploadlink) `options.isExtractableFile`.

**Type:** [ExtractableFileMatcher](#type-extractablefilematcher)

| Parameter | Type | Description     |
| :-------- | :--- | :-------------- |
| `value`   | \*   | Value to check. |

**Returns:** boolean — Is the value an extractable file.

#### See

- [`extract-files` `isExtractableFile` docs](https://github.com/jaydenseric/extract-files#function-isextractablefile).

#### Examples

_Ways to `import`._

> ```js
> import { isExtractableFile } from 'apollo-upload-client';
> ```
>
> ```js
> import isExtractableFile from 'apollo-upload-client/public/isExtractableFile.js';
> ```

_Ways to `require`._

> ```js
> const { isExtractableFile } = require('apollo-upload-client');
> ```
>
> ```js
> const isExtractableFile = require('apollo-upload-client/public/isExtractableFile');
> ```

---

### type ExtractableFileMatcher

A function that checks if a value is an extractable file.

**Type:** Function

| Parameter | Type | Description     |
| :-------- | :--- | :-------------- |
| `value`   | \*   | Value to check. |

**Returns:** boolean — Is the value an extractable file.

#### See

- [`isExtractableFile`](#function-isextractablefile) has this type.

#### Examples

_How to check for the default exactable files, as well as a custom type of file._

> ```js
> import { isExtractableFile } from 'apollo-upload-client';
>
> const isExtractableFileEnhanced = (value) =>
>   isExtractableFile(value) ||
>   (typeof CustomFile !== 'undefined' && value instanceof CustomFile);
> ```

---

### type FetchOptions

GraphQL request `fetch` options.

**Type:** object

| Property      | Type    | Description                      |
| :------------ | :------ | :------------------------------- |
| `headers`     | object  | HTTP request headers.            |
| `credentials` | string? | Authentication credentials mode. |

#### See

- [Polyfillable fetch options](https://github.github.io/fetch#options).

---

### type FormDataFileAppender

Appends a file extracted from the GraphQL operation to the [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) instance used as the [`fetch`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch) `options.body` for the [GraphQL multipart request](https://github.com/jaydenseric/graphql-multipart-request-spec).

| Parameter | Type | Description |
| :-- | :-- | :-- |
| `formData` | FormData | [`FormData`](https://developer.mozilla.org/en-US/docs/Web/API/FormData) instance to append the specified file to. |
| `fieldName` | string | Field name for the file. |
| `file` | \* | File to append. The file type depends on what the [`ExtractableFileMatcher`](#type-extractablefilematcher) extracts. |

#### See

- [`formDataAppendFile`](#function-formdataappendfile) has this type.
- [`createUploadLink`](#function-createuploadlink) accepts this type in `options.formDataAppendFile`.

---

### type ReactNativeFileSubstitute

A React Native [`File`](https://developer.mozilla.org/en-US/docs/Web/API/File) substitute.

Be aware that inspecting network traffic with buggy versions of dev tools such as [Flipper](https://fbflipper.com) can interfere with the React Native `FormData` implementation, causing multipart requests to have network errors.

**Type:** object

| Property | Type | Description |
| :-- | :-- | :-- |
| `uri` | string | Filesystem path. |
| `name` | string? | File name. |
| `type` | string? | File content type. Some environments (particularly Android) require a valid MIME type; Expo `ImageResult.type` is unreliable as it can be just `image`. |

#### See

- [`extract-files` `ReactNativeFileSubstitute` docs](https://github.com/jaydenseric/extract-files#type-reactnativefilesubstitute).
- [React Native `FormData` polyfill source](https://github.com/facebook/react-native/blob/v0.45.1/Libraries/Network/FormData.js#L34).

#### Examples

_A camera roll file._

> ```js
> const fileSubstitute = {
>   uri: uriFromCameraRoll,
>   name: 'a.jpg',
>   type: 'image/jpeg',
> };
> ```