Apollo-ios: No ability to customize Content-Type header

[spencer-microsoft]

We need to be able to set the "Content-Type" header as "application/json; charset=utf-8", but the client is hardcoded to set "Content-Type" as "application/json".

This header is set here and overwritten for multi-part requests, but we need this charset added to the header for non-multi-part requests.

[koenpunt]

There's the HTTPNetworkTransportPreflightDelegate which you can implement to modify or add additional headers;

class GraphQLClient {
    init() {
        let transport = HTTPNetworkTransport(url: "https://...", delegate: self)
        let client = ApolloClient(networkTransport: transport)
        // ....
    }
}

extension GraphQLClient: HTTPNetworkTransportPreflightDelegate {
    func networkTransport(_ networkTransport: HTTPNetworkTransport, shouldSend request: URLRequest) -> Bool {
        return true
    }

    func networkTransport(_ networkTransport: HTTPNetworkTransport, willSend request: inout URLRequest) {
        request.setValue("application/json; charset=utf-8", forHTTPHeaderField: "Content-Type")
    }
}

This delegate is called after all other modifications to the request have been done;

https://github.com/apollographql/apollo-ios/blob/3f3111d0ab1334fd344691ac95f163a2a78ab3c6/Sources/Apollo/HTTPNetworkTransport.swift#L419-L427

[designatednerd]

Yep @koenpunt is exactly correct, that's where you should make this change.

[designatednerd]

@spencer-microsoft Did this help you out?

[designatednerd]

Since I haven't heard back and there is a definite way to do this, I'm going to go ahead and close this issue out. Please reopen if you are still having problems after trying the above suggestions. Thank you!

[spencer-microsoft]

Confirmed that works, thanks!