make client an interface

example/generated.go

@@ -26,7 +26,7 @@ type getViewerViewerUser struct {
 
 func getViewer(
 	ctx context.Context,
-	client *graphql.Client,
+	client graphql.Client,
 ) (*getViewerResponse, error) {
 	var retval getViewerResponse
 	err := client.MakeRequest(
@@ -47,7 +47,7 @@ query getViewer {
 // getUser gets the given user's name from their username.
 func getUser(
 	ctx context.Context,
-	client *graphql.Client,
+	client graphql.Client,
 	login string,
 ) (*getUserResponse, error) {
 	variables := map[string]interface{}{

generate/operation.go.tmpl

@@ -24,7 +24,7 @@ func {{.Name}}(
     ctx {{$.Config.ContextType}},
     {{end}}
     {{- if not $.Config.ClientGetter -}}
-    client *graphql.Client,
+    client graphql.Client,
     {{end}}
     {{- range .Args -}}
     {{.GoName}} {{.GoType}},

generate/testdata/InputObject.graphql.go

@@ -30,7 +30,7 @@ const (
 )
 
 func InputObjectQuery(
-	client *graphql.Client,
+	client graphql.Client,
 	query UserQueryInput,
 ) (*InputObjectQueryResponse, error) {
 	variables := map[string]interface{}{

generate/testdata/InterfaceNoFragments.graphql.go

@@ -94,7 +94,7 @@ func (v InterfaceNoFragmentsQueryRootTopicChildrenVideo) implementsGraphQLInterf
 }
 
 func InterfaceNoFragmentsQuery(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*InterfaceNoFragmentsQueryResponse, error) {
 	var retval InterfaceNoFragmentsQueryResponse
 	err := client.MakeRequest(

generate/testdata/ListInput.graphql.go

@@ -15,7 +15,7 @@ type ListInputQueryUser struct {
 }
 
 func ListInputQuery(
-	client *graphql.Client,
+	client graphql.Client,
 	names []string,
 ) (*ListInputQueryResponse, error) {
 	variables := map[string]interface{}{

generate/testdata/QueryWithAlias.graphql.go

@@ -15,7 +15,7 @@ type QueryWithAliasUser struct {
 }
 
 func QueryWithAlias(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*QueryWithAliasResponse, error) {
 	var retval QueryWithAliasResponse
 	err := client.MakeRequest(

generate/testdata/QueryWithDoubleAlias.graphql.go

@@ -16,7 +16,7 @@ type QueryWithDoubleAliasUser struct {
 }
 
 func QueryWithDoubleAlias(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*QueryWithDoubleAliasResponse, error) {
 	var retval QueryWithDoubleAliasResponse
 	err := client.MakeRequest(

generate/testdata/QueryWithEnums.graphql.go

@@ -22,7 +22,7 @@ const (
 )
 
 func QueryWithEnums(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*QueryWithEnumsResponse, error) {
 	var retval QueryWithEnumsResponse
 	err := client.MakeRequest(

generate/testdata/QueryWithSlices.graphql.go

@@ -18,7 +18,7 @@ type QueryWithSlicesUser struct {
 }
 
 func QueryWithSlices(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*QueryWithSlicesResponse, error) {
 	var retval QueryWithSlicesResponse
 	err := client.MakeRequest(

generate/testdata/QueryWithStructs.graphql.go

@@ -20,7 +20,7 @@ type QueryWithStructsUserAuthMethodsAuthMethod struct {
 }
 
 func QueryWithStructs(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*QueryWithStructsResponse, error) {
 	var retval QueryWithStructsResponse
 	err := client.MakeRequest(

generate/testdata/SimpleInput.graphql.go

@@ -15,7 +15,7 @@ type SimpleInputQueryUser struct {
 }
 
 func SimpleInputQuery(
-	client *graphql.Client,
+	client graphql.Client,
 	name string,
 ) (*SimpleInputQueryResponse, error) {
 	variables := map[string]interface{}{

generate/testdata/SimpleQuery.graphql.go

@@ -15,7 +15,7 @@ type SimpleQueryUser struct {
 }
 
 func SimpleQuery(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*SimpleQueryResponse, error) {
 	var retval SimpleQueryResponse
 	err := client.MakeRequest(

generate/testdata/TypeName.graphql.go

@@ -16,7 +16,7 @@ type TypeNameQueryUser struct {
 }
 
 func TypeNameQuery(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*TypeNameQueryResponse, error) {
 	var retval TypeNameQueryResponse
 	err := client.MakeRequest(

generate/testdata/UnionNoFragments.graphql.go

@@ -72,7 +72,7 @@ func (v *UnionNoFragmentsQueryResponse) UnmarshalJSON(b []byte) error {
 }
 
 func UnionNoFragmentsQuery(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*UnionNoFragmentsQueryResponse, error) {
 	var retval UnionNoFragmentsQueryResponse
 	err := client.MakeRequest(

generate/testdata/UsesEnumTwice.graphql.go

@@ -34,7 +34,7 @@ type UsesEnumTwiceQueryResponse struct {
 }
 
 func UsesEnumTwiceQuery(
-	client *graphql.Client,
+	client graphql.Client,
 ) (*UsesEnumTwiceQueryResponse, error) {
 	var retval UsesEnumTwiceQueryResponse
 	err := client.MakeRequest(

generate/testdata/unexported.graphql.go

@@ -30,7 +30,7 @@ const (
 )
 
 func unexported(
-	client *graphql.Client,
+	client graphql.Client,
 	query userQueryInput,
 ) (*unexportedResponse, error) {
 	variables := map[string]interface{}{

graphql/client.go

@@ -10,17 +10,57 @@ import (
 	"github.com/vektah/gqlparser/gqlerror"
 )
 
-type Client struct {
+// Client is the interface that the generate code calls into to actually make
+// requests.
+type Client interface {
+	// MakeRequest must make a request to the client's GraphQL API.
+	//
+	// ctx is the context that should be used to make this request.  If context
+	// is disabled in the genql settings, this will be set to
+	// context.Background().
+	//
+	// query is the literal string representing the GraphQL query, e.g.
+	// `query myQuery { myField }`.  variables contains the GraphQL variables
+	// to be sent along with the query, or may be nil if there are none.
+	// Typically, GraphQL APIs will accept a JSON payload of the form
+	//	{"query": "query myQuery { ... }", "variables": {...}}`
+	// but MakeRequest may use some other transport, handle extensions, or set
+	// other parameters, if it wishes.
+	//
+	// retval is a pointer to the struct representing the query result, e.g.
+	// new(myQueryResponse).  Typically, GraphQL APIs will return a JSON
+	// payload of the form
+	//	{"data": {...}, "errors": {...}}
+	// and retval is designed so that `data` will json-unmarshal into `retval`.
+	// (Errors are returned.) But again, MakeRequest may customize this.
+	MakeRequest(
+		ctx context.Context,
+		query string,
+		retval interface{},
+		variables map[string]interface{},
+	) error
+}
+
+type client struct {
 	endpoint   string
 	method     string
 	httpClient *http.Client
 }
 
-func NewClient(endpoint string, httpClient *http.Client) *Client {
+// NewClient returns a Client which makes requests to the given endpoint,
+// suitable for most users.
+//
+// The client makes requests to the given GraphQL endpoint using standard
+// GraphQL HTTP-over-JSON transport.  It will use the given http client, or
+// http.DefaultClient if a nil client is passed.
+//
+// The typical method of adding authentication headers is to wrap the client's
+// Transport to add those headers.  See example/caller.go for an example.
+func NewClient(endpoint string, httpClient *http.Client) Client {
 	if httpClient == nil {
 		httpClient = http.DefaultClient
 	}
-	return &Client{endpoint, http.MethodPost, httpClient}
+	return &client{endpoint, http.MethodPost, httpClient}
 }
 
 type payload struct {
@@ -33,7 +73,7 @@ type response struct {
 	Errors gqlerror.List   `json:"errors"`
 }
 
-func (client *Client) MakeRequest(ctx context.Context, query string, retval interface{}, variables map[string]interface{}) error {
+func (client *client) MakeRequest(ctx context.Context, query string, retval interface{}, variables map[string]interface{}) error {
 	body, err := json.Marshal(payload{
 		Query:     query,
 		Variables: variables,