feat: add ExecRawWithExtensions method for retrieving extensions in r…

…esponse

README.md

@@ -818,6 +818,23 @@ if err != nil {
 err = json.Unmarshal(raw, &res)
 ```
 
+Additionally, if you need information about the extensions returned in the response use `ExecRawWithExtensions`. This function returns a map with extensions as the second variable.
+
+```Go
+query := `query{something(where: { foo: { _eq: "bar" }}){id}}`
+var res struct {
+	Somethings []Something `json:"something"`
+}
+
+data, extensions, err := client.ExecRawWithExtensions(ctx, query, map[string]any{})
+if err != nil {
+	panic(err)
+}
+
+// You can now use the `extensions` variable to access the extensions data
+fmt.Println("Extensions:", extensions)
+```
+
 ### With operation name (deprecated)
 
 Operation name is still on API decision plan https://github.com/shurcooL/graphql/issues/12. However, in my opinion separate methods are easier choice to avoid breaking changes

graphql.go

@@ -116,11 +116,12 @@ func (c *Client) buildAndRequest(ctx context.Context, op operationType, v interf
 		return nil, nil, nil, Errors{newError(ErrGraphQLEncode, err)}
 	}
 
-	return c.request(ctx, query, variables, optionOutput)
+	data, _, resp, respBuf, errs := c.request(ctx, query, variables, optionOutput)
+	return data, resp, respBuf, errs
 }
 
 // Request the common method that send graphql request
-func (c *Client) request(ctx context.Context, query string, variables map[string]interface{}, options *constructOptionsOutput) ([]byte, *http.Response, io.Reader, Errors) {
+func (c *Client) request(ctx context.Context, query string, variables map[string]interface{}, options *constructOptionsOutput) ([]byte, map[string][]byte, *http.Response, io.Reader, Errors) {
 	in := GraphQLRequestPayload{
 		Query:     query,
 		Variables: variables,
@@ -133,7 +134,7 @@ func (c *Client) request(ctx context.Context, query string, variables map[string
 	var buf bytes.Buffer
 	err := json.NewEncoder(&buf).Encode(in)
 	if err != nil {
-		return nil, nil, nil, Errors{newError(ErrGraphQLEncode, err)}
+		return nil, nil, nil, nil, Errors{newError(ErrGraphQLEncode, err)}
 	}
 
 	reqReader := bytes.NewReader(buf.Bytes())
@@ -143,7 +144,7 @@ func (c *Client) request(ctx context.Context, query string, variables map[string
 		if c.debug {
 			e = e.withRequest(request, reqReader)
 		}
-		return nil, nil, nil, Errors{e}
+		return nil, nil, nil, nil, Errors{e}
 	}
 	request.Header.Add("Content-Type", "application/json")
 
@@ -162,7 +163,7 @@ func (c *Client) request(ctx context.Context, query string, variables map[string
 		if c.debug {
 			e = e.withRequest(request, reqReader)
 		}
-		return nil, nil, nil, Errors{e}
+		return nil, nil, nil, nil, Errors{e}
 	}
 	defer resp.Body.Close()
 
@@ -171,7 +172,7 @@ func (c *Client) request(ctx context.Context, query string, variables map[string
 	if resp.Header.Get("Content-Encoding") == "gzip" {
 		gr, err := gzip.NewReader(r)
 		if err != nil {
-			return nil, nil, nil, Errors{newError(ErrJsonDecode, fmt.Errorf("problem trying to create gzip reader: %w", err))}
+			return nil, nil, nil, nil, Errors{newError(ErrJsonDecode, fmt.Errorf("problem trying to create gzip reader: %w", err))}
 		}
 		defer gr.Close()
 		r = gr
@@ -187,20 +188,21 @@ func (c *Client) request(ctx context.Context, query string, variables map[string
 		if c.debug {
 			err = err.withRequest(request, reqReader)
 		}
-		return nil, nil, nil, Errors{err}
+		return nil, nil, nil, nil, Errors{err}
 	}
 
 	var out struct {
-		Data   *json.RawMessage
-		Errors Errors
+		Data       *json.RawMessage
+		Extensions map[string]*json.RawMessage
+		Errors     Errors
 	}
 
 	// copy the response reader for debugging
 	var respReader *bytes.Reader
 	if c.debug {
 		body, err := io.ReadAll(resp.Body)
 		if err != nil {
-			return nil, nil, nil, Errors{newError(ErrJsonDecode, err)}
+			return nil, nil, nil, nil, Errors{newError(ErrJsonDecode, err)}
 		}
 		respReader = bytes.NewReader(body)
 		r = io.NopCloser(respReader)
@@ -218,25 +220,37 @@ func (c *Client) request(ctx context.Context, query string, variables map[string
 			we = we.withRequest(request, reqReader).
 				withResponse(resp, respReader)
 		}
-		return nil, nil, nil, Errors{we}
+		return nil, nil, nil, nil, Errors{we}
 	}
 
 	var rawData []byte
 	if out.Data != nil && len(*out.Data) > 0 {
 		rawData = []byte(*out.Data)
 	}
 
+	var extensions map[string][]byte
+	if out.Extensions != nil {
+		extensions = make(map[string][]byte, len(out.Extensions))
+		for k, v := range out.Extensions {
+			if v != nil {
+				extensions[k] = []byte(*v)
+			} else {
+				extensions[k] = nil
+			}
+		}
+	}
+
 	if len(out.Errors) > 0 {
 		if c.debug && (out.Errors[0].Extensions == nil || out.Errors[0].Extensions["request"] == nil) {
 			out.Errors[0] = out.Errors[0].
 				withRequest(request, reqReader).
 				withResponse(resp, respReader)
 		}
 
-		return rawData, resp, respReader, out.Errors
+		return rawData, extensions, resp, respReader, out.Errors
 	}
 
-	return rawData, resp, respReader, nil
+	return rawData, extensions, resp, respReader, nil
 }
 
 // do executes a single GraphQL operation.
@@ -263,7 +277,7 @@ func (c *Client) Exec(ctx context.Context, query string, v interface{}, variable
 		return err
 	}
 
-	data, resp, respBuf, errs := c.request(ctx, query, variables, optionsOutput)
+	data, _, resp, respBuf, errs := c.request(ctx, query, variables, optionsOutput)
 	return c.processResponse(v, data, resp, respBuf, errs)
 }
 
@@ -275,13 +289,29 @@ func (c *Client) ExecRaw(ctx context.Context, query string, variables map[string
 		return nil, err
 	}
 
-	data, _, _, errs := c.request(ctx, query, variables, optionsOutput)
+	data, _, _, _, errs := c.request(ctx, query, variables, optionsOutput)
 	if len(errs) > 0 {
 		return data, errs
 	}
 	return data, nil
 }
 
+// Executes a pre-built query and returns the raw json message and a map with extensions (values also as raw json objects). Unlike the
+// Query method you have to specify in the query the fields that you want to receive as they are not inferred from the interface. This method
+// is useful if you need to build the query dynamically.
+func (c *Client) ExecRawWithExtensions(ctx context.Context, query string, variables map[string]interface{}, options ...Option) ([]byte, map[string][]byte, error) {
+	optionsOutput, err := constructOptions(options)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	data, ext, _, _, errs := c.request(ctx, query, variables, optionsOutput)
+	if len(errs) > 0 {
+		return data, ext, errs
+	}
+	return data, ext, nil
+}
+
 func (c *Client) processResponse(v interface{}, data []byte, resp *http.Response, respBuf io.Reader, errs Errors) error {
 	if len(data) > 0 {
 		err := jsonutil.UnmarshalGraphQL(data, v)

graphql_test.go

@@ -470,6 +470,81 @@ func TestClient_Exec_QueryRaw(t *testing.T) {
 	}
 }
 
+// Test exec pre-built query, return raw json string and map
+// with extensions
+func TestClient_Exec_QueryRawWithExtensions(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/graphql", func(w http.ResponseWriter, req *http.Request) {
+		body := mustRead(req.Body)
+		if got, want := body, `{"query":"{user{id,name}}"}`+"\n"; got != want {
+			t.Errorf("got body: %v, want %v", got, want)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		mustWrite(w, `{"data": {"user": {"name": "Gopher"}}, "extensions": {"domain": "users", "database": {"id": 1, "name": "users_db"}}"}`)
+	})
+	client := graphql.NewClient("/graphql", &http.Client{Transport: localRoundTripper{handler: mux}})
+
+	var database struct {
+		ID   int    `graphql:"id"`
+		Name string `graphql:"name"`
+	}
+
+	_, extensions, err := client.ExecRawWithExtensions(context.Background(), "{user{id,name}}", map[string]interface{}{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got, want := len(extensions), 2; got != want {
+		t.Errorf("got len(extensions): %q, want: %q", got, want)
+	}
+
+	var domain string
+	err = json.Unmarshal(extensions["domain"], &domain)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got, want := domain, "users"; got != want {
+		t.Errorf("got domain: %q, want: %q", got, want)
+	}
+
+	err = json.Unmarshal(extensions["database"], &database)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got, want := database.ID, 1; got != want {
+		t.Errorf("got database.ID: %q, want: %q", got, want)
+	}
+	if got, want := database.Name, "users_db"; got != want {
+		t.Errorf("got database.Name: %q, want: %q", got, want)
+	}
+}
+
+// Test exec pre-built query, return raw json string and map
+// with extension set to `null`
+func TestClient_Exec_QueryRawWithNullExtension(t *testing.T) {
+	mux := http.NewServeMux()
+	mux.HandleFunc("/graphql", func(w http.ResponseWriter, req *http.Request) {
+		body := mustRead(req.Body)
+		if got, want := body, `{"query":"{user{id,name}}"}`+"\n"; got != want {
+			t.Errorf("got body: %v, want %v", got, want)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		mustWrite(w, `{"data": {"user": {"name": "Gopher"}}, "extensions": {"domain": null}}`)
+	})
+	client := graphql.NewClient("/graphql", &http.Client{Transport: localRoundTripper{handler: mux}})
+
+	_, extensions, err := client.ExecRawWithExtensions(context.Background(), "{user{id,name}}", map[string]interface{}{})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if got := extensions["domain"]; got != nil {
+		t.Errorf("got non-nil extensions[\"domain\"]: %q, want: nil", got)
+	}
+}
+
 // localRoundTripper is an http.RoundTripper that executes HTTP transactions
 // by using handler directly, instead of going over an HTTP connection.
 type localRoundTripper struct {