Subscriptions

[D1plo1d]

Not sure how much work this is to implement but support for graphql-js compatible subscriptions (maybe with an experimental flag or something?) would be super-useful and really appreciated.

I (very foolishly) assumed libgraphqlparser would support subscriptions when we started building on top of it. Now we've got a whole ruby GraphQL DSL built and nowhere to subscribe :(

Related Conversations:

• https://github.com/Shopify/graphql-parser/pull/8
• [WIP] adding 'subscription' language to GraphQL spec graphql-spec#109

[swolchok]

Does the attached commit work for you? Seems legit from the tests I added, but I would like to have other eyes on it before I merge it to master.

[D1plo1d]

The graphql-parser gem seems to have an issue with this branch. I'm not a C++ person, any idea what's going on here:

Installing graphql-parser 0.0.2 with native extensions

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /Users/robgilson/.rbenv/versions/2.2.2/bin/ruby -r ./siteconf20160429-11555-1e20m4.rb extconf.rb
checking for main() in -lgraphqlparser... yes
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling graphql_parser.c
compiling graphql_ruby.c
graphql_ruby.c:514:18: warning: implicit declaration of function 'GraphQLAstArrayValue_get_values_size' is invalid in C99 [-Wimplicit-function-declaration]
  return INT2FIX(GraphQLAstArrayValue_get_values_size(node));
                 ^
/Users/robgilson/.rbenv/versions/2.2.2/include/ruby-2.2.0/ruby/ruby.h:234:30: note: expanded from macro 'INT2FIX'
#define INT2FIX(i) (((VALUE)(i))<<1 | FIXNUM_FLAG)
                             ^
graphql_ruby.c:889:7: error: no member named 'visit_array_value' in 'struct GraphQLAstVisitorCallbacks'; did you mean 'visit_float_value'?
  cbs.visit_array_value = visit_array_value;
      ^~~~~~~~~~~~~~~~~
      visit_float_value
/usr/local/include/graphqlparser/c/GraphQLAstVisitor.h:38:26: note: 'visit_float_value' declared here
  FOR_EACH_CONCRETE_TYPE(FUNC_MEMBER)
                         ^
/usr/local/include/graphqlparser/c/GraphQLAstForEachConcreteType.h:21:28: note: expanded from macro 'FOR_EACH_CONCRETE_TYPE'
MACRO(IntValue, int_value) \
                           ^
/usr/local/include/graphqlparser/c/GraphQLAstVisitor.h:26:29: note: expanded from macro 'FUNC_MEMBER'
  visit_##snake_type##_func visit_##snake_type; \
                            ^
<scratch space>:68:1: note: expanded from here
visit_float_value
^
graphql_ruby.c:889:25: warning: incompatible pointer types assigning to 'visit_float_value_func' (aka 'int (*)(const struct GraphQLAstFloatValue *, void *)') from 'int (const struct GraphQLAstArrayValue *, void *)' [-Wincompatible-pointer-types]
  cbs.visit_array_value = visit_array_value;
                        ^ ~~~~~~~~~~~~~~~~~
graphql_ruby.c:890:7: error: no member named 'end_visit_array_value' in 'struct GraphQLAstVisitorCallbacks'; did you mean 'end_visit_float_value'?
  cbs.end_visit_array_value = end_visit_array_value;
      ^~~~~~~~~~~~~~~~~~~~~
      end_visit_float_value
/usr/local/include/graphqlparser/c/GraphQLAstVisitor.h:38:26: note: 'end_visit_float_value' declared here
  FOR_EACH_CONCRETE_TYPE(FUNC_MEMBER)
                         ^
/usr/local/include/graphqlparser/c/GraphQLAstForEachConcreteType.h:21:28: note: expanded from macro 'FOR_EACH_CONCRETE_TYPE'
MACRO(IntValue, int_value) \
                           ^
/usr/local/include/graphqlparser/c/GraphQLAstVisitor.h:27:33: note: expanded from macro 'FUNC_MEMBER'
  end_visit_##snake_type##_func end_visit_##snake_type;
                                ^
<scratch space>:71:1: note: expanded from here
end_visit_float_value
^
graphql_ruby.c:890:29: warning: incompatible pointer types assigning to 'end_visit_float_value_func' (aka 'void (*)(const struct GraphQLAstFloatValue *, void *)') from 'void (const struct GraphQLAstArrayValue *, void *)' [-Wincompatible-pointer-types]
  cbs.end_visit_array_value = end_visit_array_value;
                            ^ ~~~~~~~~~~~~~~~~~~~~~
3 warnings and 2 errors generated.
make: *** [graphql_ruby.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/robgilson/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/gems/graphql-parser-0.0.2 for inspection.
Results logged to /Users/robgilson/.rbenv/versions/2.2.2/lib/ruby/gems/2.2.0/extensions/x86_64-darwin-15/2.2.0-static/graphql-parser-0.0.2/gem_make.out

[swolchok]

Looks like the graphql-parser gem hasn't been updated to be compatible with this API-breaking change on master (which corrects an API difference from graphql-js): 5b83654

That's probably because I haven't cut a versioned release since making that change. I'll fix that, though I'd prefer to include subscription support rather than do a point release just for that.

To fix it in graphql-parser, you probably just need to change array_value to list_value.

[swolchok]

I also had to change GraphQLAstArrayValue to GraphQLAstListValue locally. Here are the find/replace commands I used, in the graphql-parser directory:

perl -p -i -e 's|array_value|list_value|g' $(git grep -l array_value)
perl -p -i -e 's|ArrayValue|ListValue|g' $(git grep -l ArrayValue)

Hope this helps!

[D1plo1d]

I've set up a fork of graphql-parser with your changes and added test for subscriptions but it isn't passing yet. Not sure why:

https://github.com/D1plo1d/graphql-parser/tree/feature/subscriptions

You can run the tests with: bundle install & rake compile & rake test

[D1plo1d]

Nm, typos strike again! Totally works :)

[D1plo1d]

w00t! Thanks @swolchok!