Files
genqlient/generate/operation.go.tmpl
T
Ben Kraft 5995653583 Refactor argument-handling to use a struct (#103)
## Summary:
In this commit I refactor the argument-generation logic to move most of
the code out of the template and into the type-generator.  This logic
predates #51, and I didn't think to update it there, but I think it
benefits from similar treatment, for similar reasons.

Specifically, the main change is to treat variables as another struct
type we can generate, rather than handling them inline as a
`map[string]interface{}`.  Users still pass them the same way, but
instead of putting them into a `map[string]interface{}` and JSONifying
that, we generate a struct and put them there.

This turns out to simplify things quite a lot, because we already have a
lot of code to generate types.  Notably, the omitempty code goes from a
dozen lines to basically two, and fixes a bug (#43) in the process,
because now that we have a struct, `json.Marshal` will do our work for
us! (And, once we have syntax for it (#14), we'll be able to handle
field-level omitempty basically for free.)  More importantly, it will
simplify custom marshalers (#38, forthcoming) significantly, since we do
all that logic at the containing-struct level, but will need to apply it
to arguments.

It does require two breaking changes:

1. For folks implementing the `graphql.Client` API (rather than just
   calling `NewClient`): we now pass them variables as an `interface{}`
   rather than a `map[string]interface{}`.  For most callers, including
   Khan/webapp, this is basically a one-line change to the signature of
   their `MakeRequest`, and it should be a lot more future-proof.
2. genqlient's handling of the `omitempty` option has changed to match
   that of `encoding/json`, in particular it now never considers structs
   "empty".  The difference was never intentional (I just didn't realize
   that behavior of `encoding/json`); arguably our behavior was more
   useful but I think that's outweighed by the value of consistency with
   `encoding/json` as well as the simpler and more correct
   implementation (fixing #43 is actually quite nontrivial otherwise).
   Once we have custom unmarshaler support (#38), users will be able to
   map a zero value to JSON null if they wish, which is mostly if not
   entirely equivalent for GraphQL's purposes.

Issue: https://github.com/Khan/genqlient/issues/38
Issue: https://github.com/Khan/genqlient/issues/43

## Test plan:
make check

Author: benjaminjkraft

Reviewers: StevenACoffman, dnerdy, aberkan, jvoll, mahtabsabet, MiguelCastillo

Required Reviewers: 

Approved By: StevenACoffman, dnerdy

Checks:  Test (1.17),  Test (1.16),  Test (1.15),  Test (1.14),  Lint,  Lint,  Test (1.17),  Test (1.16),  Test (1.15),  Test (1.14)

Pull Request URL: https://github.com/Khan/genqlient/pull/103
2021-09-22 17:16:36 -07:00

46 lines
1.4 KiB
Cheetah

{{.Doc}}
func {{.Name}}(
{{if ne .Config.ContextType "-" -}}
ctx {{ref .Config.ContextType}},
{{end}}
{{- if not .Config.ClientGetter -}}
client {{ref "github.com/Khan/genqlient/graphql.Client"}},
{{end}}
{{- if .Input -}}
{{- range .Input.Fields -}}
{{/* the GraphQL name here is the user-specified variable-name */ -}}
{{.GraphQLName}} {{.GoType.Reference}},
{{end -}}
{{end -}}
) (*{{.ResponseName}}, error) {
{{- if .Input -}}
{{/* We need to avoid conflicting with any of the function's argument names
which are derived from the GraphQL argument names; notably `input` is
a common one. So we use a name that's not legal in GraphQL, namely
one starting with a double-underscore. */ -}}
__input := {{.Input.GoName}}{
{{range .Input.Fields -}}
{{.GoName}}: {{.GraphQLName}},
{{end -}}
}
{{end -}}
var err error
{{if .Config.ClientGetter -}}
client, err := {{ref .Config.ClientGetter}}({{if ne .Config.ContextType "-"}}ctx{{else}}{{end}})
if err != nil {
return nil, err
}
{{end}}
var retval {{.ResponseName}}
err = client.MakeRequest(
{{if ne .Config.ContextType "-"}}ctx{{else}}nil{{end}},
"{{.Name}}",
`{{.Body}}`,
&retval,
{{if .Input}}&__input{{else}}nil{{end}},
)
return &retval, err
}