Add file uploads [RFC] [WIP]

[JustinDSN]

Add Upload Support to Apollo-iOS

• GraphQL Multipart Request Spec by @jaydenseric.

Depends on:

• Bump fstream from 1.0.11 to 1.0.12 starwars-server#9

Summary of Changes:

• Adds a new protocol GraphQLUpload and typealias for Upload.
• Adds new structs for DataGraphQLUpload, FileGraphQLUpload, InputStreamGraphQLUpload to allow clients flexibility to supply an uploads.
• Adds a new protocol GraphQLUploadOperation which inherits from GraphQLOperation.
• Adds a new protocol GraphQLUploadMutation which inherits from GraphQLUploadOperation.
• Adds a public function to ApolloClient to perform GraphQLUploadMutations
• Changes generic constraints on Operation type on NetworkTransport protocol.
• Adds a new requirement to send<Operation: GraphQLUploadOperation> on NetworkTransport protocol.
• Added implementation for send<Operation: GraphQLUploadOperation> in HTTPNetworkTransport.
• Adds AlamoFire's MultipartForm, AFError, and HTTPHeaders to provide robust MultipartFrom encoding.

TODO:

• [] Change apollo-cli to generate GraphQLUploadMutations correctly.
• [] Implement multipart encoding memory thresholds to either write to disk or stream from memory.

[MrAlek]

This property should preferably be a stream instead of actual bytes. For large upload, you don't want to load the entire file into memory at once.

You mentioned you have had a look at https://github.com/Alamofire/Alamofire/blob/master/Source/MultipartFormData.swift ?

[JustinDSN]

I just pushed a revision that supports Data, File, and InputStream variants of uploads.

[MrAlek]

Great initiative! At Dooer, we've implemented uploads very similarly with the exception of using Alamofire's multipart serializer, utilizing streams.

[martijnwalraven]

This looks great!

I hope we can avoid the code duplication for GraphQLUploadMutation however, and rely on protocol composition instead. There might be subtleties here in how method dispatch works, so we may need more explicit checks to dispatch to the right method in HTTPNetworkTransport, but the idea would be to use GraphQLMutation & GraphQLUploadOperation as the type instead of GraphQLUploadMutation.

Does that make sense to you or am I missing something?

[victormihaita]

Hi guys. Do you have by any chance any updates for this PR?

[JustinDSN]

Hi @victormihaita, I'm sorry for the delay, but this PR took a back burner for a little while.

I've addressed the comments left by @martijnwalraven, but it's been a while since we've collaborated on this, so we'll have to see if we can get this off the shelves.

@martijnwalraven from my perspective heres the checklist:

• [] Review and merge Bump js-yaml from 3.8.3 to 3.13.1 starwars-server#10, this will allow the unit-tests I've written in this PR to pass.
• [] Change apollo-cli to generate GraphQLUploadMutations correctly as a separate PR. Can someone from the Apollo team help with this?
• [] Implement multipart encoding memory thresholds to either write to disk or stream from memory as a separate PR.

What do you think? Do you think we should approach it this way or some other way. I'm also very curious how many members of the community are looking for this?

[victormihaita]

This feature is something that we are really looking forward to have it. Right now, we had to create a separate REST Endpoint in our API just for uploading images (while the rest of it is based on GraphQL), and this was made just for the iOS client... I consider it as a really important feature for a networking service such as Apollo... it would be great if we can see any progress in this direction :) @martijnwalraven @JustinDSN

[designatednerd]

Hey @JustinDSN - thanks for your hard work on this, and apologies this was left fallow for so long. Do you have any thoughts on rebasing this vs moving forward with the simpler implementation in #626?

[designatednerd]

I've gone ahead and merged #626 - I'm going to close this one out, but please feel free to open a new PR if there's anything that's missing from the implementation there!