feat: implement websocket subprotocols for subscriptions graphql-ws, graphql-transport-ws

[pankgeorg]

Implements https://github.com/apollographql/subscriptions-transport-ws/blob/master/PROTOCOL.md and the newer and currently maintained https://github.com/enisdenjo/graphql-ws/blob/master/PROTOCOL.md

WebSocket subscription works on Hasura 2.14.0-beta-1 with this patch, using both protocols.

One can choose protocol (sub-protocol) by using the kwargument to open_subscription: websocket_protocol. By default this is set to "graphql-ws, graphql-transport-ws" which leaves the decision up to the server. It can be overriden with any of the two values; GraphQLClient.PROTOCOL_GRAPHQL_WS or GraphQLClient.PROTOCOL_APOLLO_OLD. In that case, the client will explicitly request one protocol (and the server should comply - if it doesn't we adapt).

Includes #19 so le'ts put that in first.

[codecov-commenter]

Codecov Report

Merging #21 (ad669c8) into main (d6e6ac2) will decrease coverage by 10.15%.
The diff coverage is 23.57%.

@@             Coverage Diff             @@
##             main      #21       +/-   ##
===========================================
- Coverage   67.27%   57.12%   -10.16%     
===========================================
  Files          17       18        +1     
  Lines         602      702      +100     
===========================================
- Hits          405      401        -4     
- Misses        197      301      +104     

Impacted Files	Coverage Δ
src/GraphQLClient.jl	100.00% <ø> (ø)
src/ws_subscription_protocols.jl	10.81% <10.81%> (ø)
src/subscriptions.jl	80.82% <71.42%> (-8.47%)	⬇️
src/gqlresponse.jl	24.32% <100.00%> (ø)

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[pankgeorg]

On version 0.7.5 opening a subscription to a Hasura 2.14.0-beta-ce server retrurns

`Cannot `convert` an object of type Nothing to an object of type String`

julia> open_subscription(client, "jobs", output_fields=["id"], verbose=2) do r
              @info "got results"
                     return false
                            end
Starting jobs subscription with ID 1-1
Listening to jobs with ID 1-1...
ERROR: MethodError: Cannot `convert` an object of type Nothing to an object of type String
Closest candidates are:
  convert(::Type{String}, ::String) at essentials.jl:218
  convert(::Type{T}, ::T) where T<:AbstractString at strings/basic.jl:231
  convert(::Type{T}, ::AbstractString) where T<:AbstractString at strings/basic.jl:232
  ...
Stacktrace:
  [1] GraphQLClient.GQLSubscriptionResponse{Any}(id::Nothing, type::String, payload::Nothing)
    @ GraphQLClient ~/GraphQLClient.jl/src/gqlresponse.jl:102
  [2] construct
    @ ~/.julia/packages/StructTypes/AK4aM/src/StructTypes.jl:912 [inlined]
  [3] read(::StructTypes.UnorderedStruct, buf::Vector{UInt8}, pos::Int64, len::Int64, b::UInt8, ::Type{GraphQLClient.GQLSubscriptionResponse{Any}}; kw::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ JSON3 ~/.julia/packages/JSON3/vguNZ/src/structs.jl:645
  [4] read
    @ ~/.julia/packages/JSON3/vguNZ/src/structs.jl:566 [inlined]
  [5] read(str::JSON3.VectorString{Vector{UInt8}}, ::Type{GraphQLClient.GQLSubscriptionResponse{Any}}; jsonlines::Bool, kw::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
    @ JSON3 ~/.julia/packages/JSON3/vguNZ/src/structs.jl:40
  [6] read
    @ ~/.julia/packages/JSON3/vguNZ/src/structs.jl:32 [inlined]
  [7] #read#15
    @ ~/.julia/packages/JSON3/vguNZ/src/structs.jl:14 [inlined]
  [8] read(bytes::Vector{UInt8}, ::Type{GraphQLClient.GQLSubscriptionResponse{Any}})
    @ JSON3 ~/.julia/packages/JSON3/vguNZ/src/structs.jl:14
  [9] (::GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String})(ws::HTTP.WebSockets.WebSocket{HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}})
    @ GraphQLClient ~/GraphQLClient.jl/src/subscriptions.jl:123
 [10] (::HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String})(http::HTTP.Streams.Stream{HTTP.Messages.Response, HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}})
    @ HTTP.WebSockets ~/.julia/packages/HTTP/aTjcj/src/WebSockets.jl:124
 [11] macro expansion
    @ ~/.julia/packages/HTTP/aTjcj/src/StreamRequest.jl:70 [inlined]
 [12] macro expansion
    @ ./task.jl:454 [inlined]
 [13] request(::Type{HTTP.StreamRequest.StreamLayer{Union{}}}, io::HTTP.ConnectionPool.Transaction{Sockets.TCPSocket}, req::HTTP.Messages.Request, body::Nothing; reached_redirect_limit::Bool, response_stream::Nothing, iofunction::HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, verbose::Int64, kw::Base.Pairs{Symbol, Bool, Tuple{Symbol}, NamedTuple{(:retry,), Tuple{Bool}}})
    @ HTTP.StreamRequest ~/.julia/packages/HTTP/aTjcj/src/StreamRequest.jl:57
 [14] request(::Type{HTTP.ConnectionRequest.ConnectionPoolLayer{HTTP.StreamRequest.StreamLayer{Union{}}}}, url::URIs.URI, req::HTTP.Messages.Request, body::Nothing; proxy::Nothing, socket_type::Type, reuse_limit::Int64, kw::Base.Pairs{Symbol, Any, NTuple{4, Symbol}, NamedTuple{(:iofunction, :reached_redirect_limit, :verbose, :retry), Tuple{HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, Bool, Int64, Bool}}})
    @ HTTP.ConnectionRequest ~/.julia/packages/HTTP/aTjcj/src/ConnectionRequest.jl:108
 [15] request(::Type{HTTP.ExceptionRequest.ExceptionLayer{HTTP.ConnectionRequest.ConnectionPoolLayer{HTTP.StreamRequest.StreamLayer{Union{}}}}}, ::URIs.URI, ::Vararg{Any}; kw::Base.Pairs{Symbol, Any, NTuple{5, Symbol}, NamedTuple{(:iofunction, :reached_redirect_limit, :reuse_limit, :verbose, :retry), Tuple{HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, Bool, Int64, Int64, Bool}}})
    @ HTTP.ExceptionRequest ~/.julia/packages/HTTP/aTjcj/src/ExceptionRequest.jl:19
 [16] (::Base.var"#88#90"{Base.var"#88#89#91"{ExponentialBackOff, HTTP.RetryRequest.var"#2#3"{Bool, HTTP.Messages.Request}, typeof(HTTP.request)}})(::Type, ::Vararg{Any}; kwargs::Base.Pairs{Symbol, Any, NTuple{5, Symbol}, NamedTuple{(:iofunction, :reached_redirect_limit, :reuse_limit, :verbose, :retry), Tuple{HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, Bool, Int64, Int64, Bool}}})
    @ Base ./error.jl:296
 [17] #request#1
    @ ~/.julia/packages/HTTP/aTjcj/src/RetryRequest.jl:44 [inlined]
 [18] request(::Type{HTTP.MessageRequest.MessageLayer{HTTP.RetryRequest.RetryLayer{HTTP.ExceptionRequest.ExceptionLayer{HTTP.ConnectionRequest.ConnectionPoolLayer{HTTP.StreamRequest.StreamLayer{Union{}}}}}}}, method::String, url::URIs.URI, headers::Vector{Pair{SubString{String}, SubString{String}}}, body::Nothing; http_version::VersionNumber, target::String, parent::Nothing, iofunction::Function, kw::Base.Pairs{Symbol, Integer, NTuple{4, Symbol}, NamedTuple{(:reached_redirect_limit, :reuse_limit, :verbose, :retry), Tuple{Bool, Int64, Int64, Bool}}})
    @ HTTP.MessageRequest ~/.julia/packages/HTTP/aTjcj/src/MessageRequest.jl:66
 [19] request(::Type{HTTP.BasicAuthRequest.BasicAuthLayer{HTTP.MessageRequest.MessageLayer{HTTP.RetryRequest.RetryLayer{HTTP.ExceptionRequest.ExceptionLayer{HTTP.ConnectionRequest.ConnectionPoolLayer{HTTP.StreamRequest.StreamLayer{Union{}}}}}}}}, method::String, url::URIs.URI, headers::Vector{Pair{SubString{String}, SubString{String}}}, body::Nothing; kw::Base.Pairs{Symbol, Any, NTuple{5, Symbol}, NamedTuple{(:reached_redirect_limit, :iofunction, :reuse_limit, :verbose, :retry), Tuple{Bool, HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, Int64, Int64, Bool}}})
    @ HTTP.BasicAuthRequest ~/.julia/packages/HTTP/aTjcj/src/BasicAuthRequest.jl:28
 [20] request(::Type{HTTP.RedirectRequest.RedirectLayer{HTTP.BasicAuthRequest.BasicAuthLayer{HTTP.MessageRequest.MessageLayer{HTTP.RetryRequest.RetryLayer{HTTP.ExceptionRequest.ExceptionLayer{HTTP.ConnectionRequest.ConnectionPoolLayer{HTTP.StreamRequest.StreamLayer{Union{}}}}}}}}}, method::String, url::URIs.URI, headers::Vector{Pair{SubString{String}, SubString{String}}}, body::Nothing; redirect_limit::Int64, forwardheaders::Bool, kw::Base.Pairs{Symbol, Any, NTuple{4, Symbol}, NamedTuple{(:iofunction, :reuse_limit, :verbose, :retry), Tuple{HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, Int64, Int64, Bool}}})
    @ HTTP.RedirectRequest ~/.julia/packages/HTTP/aTjcj/src/RedirectRequest.jl:28
 [21] #request#1
    @ ~/.julia/packages/HTTP/aTjcj/src/TopRequest.jl:15 [inlined]
 [22] request(method::String, url::String, h::Vector{Pair{String, String}}, b::Nothing; headers::Vector{Pair{String, String}}, body::Nothing, query::Nothing, kw::Base.Pairs{Symbol, Any, NTuple{4, Symbol}, NamedTuple{(:iofunction, :reuse_limit, :verbose, :retry), Tuple{HTTP.WebSockets.var"#3#4"{Bool, GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, String}, Int64, Int64, Bool}}})
    @ HTTP ~/.julia/packages/HTTP/aTjcj/src/HTTP.jl:330
 [23] #open#11
    @ ~/.julia/packages/HTTP/aTjcj/src/HTTP.jl:364 [inlined]
 [24] open(f::GraphQLClient.var"#35#36"{Nothing, Int64, Nothing, Bool, Int64, var"#1#2", String, DataType, String}, url::String; binary::Bool, verbose::Bool, headers::Dict{String, String}, kw::Base.Pairs{Symbol, Bool, Tuple{Symbol}, NamedTuple{(:retry,), Tuple{Bool}}})
    @ HTTP.WebSockets ~/.julia/packages/HTTP/aTjcj/src/WebSockets.jl:104
 [25] open_subscription(fn::var"#1#2", client::Client, subscription_name::String, output_type::Type; sub_args::Dict{Any, Any}, output_fields::Vector{String}, initfn::Nothing, retry::Bool, subtimeout::Int64, stopfn::Nothing, throw_on_execution_error::Bool, verbose::Int64)
    @ GraphQLClient ~/GraphQLClient.jl/src/subscriptions.jl:97
 [26] top-level scope
    @ REPL[11]:1

That happens because the server sends a keepalive message that doesn't have all the fields defined in src/gqlresponse.jl:101:

{"type": "ka"}

struct GQLSubscriptionResponse{T}
    id::String
    type::String
    payload::GQLResponse{T}
end

The simple patch to that complains about not initializing the connection properly

where the solution - at least for this server - is to align the protocols.

I'm looking for a new way to also fix the tests of the subscriptions using a server in GitHub actions.