Pass Idiomatic graphQL+- through Dgo - RPC

Users Dgraph
1

Hi there,
I am prototyping with dragph.
I am doing a Go server API that will pass my front app’s request the most directly to dgraph.
My GO API will then perform some user credential / rights scoping on the request and then send the json back to the front APP.

Basically APP-> http (graphql± request) → My GO API → rpc → Dgraph (and back :wink: )

I have been using the DGO RPC example (GitHub - dgraph-io/dgo: Official Dgraph Go client).
Also is there a way to pass IDIOMATIC graphQL± through RPC ??

For now the example does things like :

pb, err := json.Marshal(p)
if err != nil {
log.Fatal(err)
}
mu := &api.Mutation{
SetJson: pb,
}
res, err:= txn.Mutate(ctx, mu)

If I want on the App side to pass this request for example :

curl -H "Content-Type: application/rdf" localhost:8080/mutate?commitNow=true -XPOST -d $'
{
  set {
   _:luke <name> "Luke Skywalker" .
   _:luke <dgraph.type> "Person" .
   _:leia <name> "Princess Leia" .
   _:leia <dgraph.type> "Person" .
   _:han <name> "Han Solo" .
   _:han <dgraph.type> "Person" .
   _:lucas <name> "George Lucas" .
   _:lucas <dgraph.type> "Person" .
   _:irvin <name> "Irvin Kernshner" .
   _:irvin <dgraph.type> "Person" .
   _:richard <name> "Richard Marquand" .
   _:richard <dgraph.type> "Person" .

   _:sw1 <name> "Star Wars: Episode IV - A New Hope" .
   _:sw1 <release_date> "1977-05-25" .
   _:sw1 <revenue> "775000000" .
   _:sw1 <running_time> "121" .
   _:sw1 <starring> _:luke .
   _:sw1 <starring> _:leia .
   _:sw1 <starring> _:han .
   _:sw1 <director> _:lucas .
   _:sw1 <dgraph.type> "Film" .

   _:sw2 <name> "Star Wars: Episode V - The Empire Strikes Back" .
   _:sw2 <release_date> "1980-05-21" .
   _:sw2 <revenue> "534000000" .
   _:sw2 <running_time> "124" .
   _:sw2 <starring> _:luke .
   _:sw2 <starring> _:leia .
   _:sw2 <starring> _:han .
   _:sw2 <director> _:irvin .
   _:sw2 <dgraph.type> "Film" .

   _:sw3 <name> "Star Wars: Episode VI - Return of the Jedi" .
   _:sw3 <release_date> "1983-05-25" .
   _:sw3 <revenue> "572000000" .
   _:sw3 <running_time> "131" .
   _:sw3 <starring> _:luke .
   _:sw3 <starring> _:leia .
   _:sw3 <starring> _:han .
   _:sw3 <director> _:richard .
   _:sw3 <dgraph.type> "Film" .

   _:st1 <name> "Star Trek: The Motion Picture" .
   _:st1 <release_date> "1979-12-07" .
   _:st1 <revenue> "139000000" .
   _:st1 <running_time> "132" .
   _:st1 <dgraph.type> "Film" .
  }
}
'

I am new to dgraph, for now my feeling is like I have to do everything in http and not use DGO lib … really wondering.

2

If you wanna send RDF format just use txn.Mutate(ctx, mu). It accepts JSON (if so) and RDF. In case of RDF you use SetNquads and DeleteNquads instead of SetJson.

source GitHub - dgraph-io/dgo: Official Dgraph Go client

3

Thanks @MichelDiz for the answer on passing JSON,

I am progressing in my prototype, I think what I need is a way to read and modify the request when they are on my API (for validation purpose etc…).

Also it seems that I would have to manipulate strings there. Which is very un-convenient and error prone.

For example someone has tried to make a lib for this purpose here : GitHub - udacity/graphb: GraphQL Query Builder for Go
But it ends up beeing more complicated …

My understanding is that graphql requests are abstract syntax trees (AST) …

Therefore is there a golang lib to manipulate graphql as abstract syntax trees ???

4

Dunno, but is not hard to do so as far as I can tell. I had worked some time ago with graphql AST using JavaScript. It is easy as the AST is just an “object”. In JS is easy to manipulate the AST, but I have no idea of how to do the same with Go.

Cheers.

5

Hi there,
Still cannot find a way to marshall / unmarshall easily graphql requests in Golang.

I found this one that lets you create a request from scratch, but doesn t let you marshall the text request to idiomatic GO : graphb/three_ways_to_construct_query_test.go at 912b8fd361d78e00687f934aace09cf8eb054449 · udacity/graphb · GitHub

I found a way to mutate with JSON, so I can easily manipulate JSON in GO (when I receive the request from my API in Go) : https://docs.dgraph.io/mutations/#using-json-operations-via-curl

BUT there is no clue how to manipulate a request (marshall / unmarshall)??
Any help ?

Something that would look like (this doesn t work) :

curl -H "Content-Type: application/json" -X POST localhost:8080/**QUERY**?commitNow=true -d $'
    {
  me(func:allofterms(name, "Star Wars")) @filter(ge(release_date, "1980")) {
    name
    release_date
    revenue
    running_time
    director {
     name
    }
    starring {
     name
    }
  }
}'
6

Humm, I’m confused.

You had talked about Graphql’s AST. Dgraph has no AST. Only Graphql has it. Graphl+- works differently under the hood.

Can you clarify this?

7

We use this one (indirectly) GitHub - vektah/gqlparser: A port of the parser from graphql-js into golang