refactor: add generic API request helper functions (#572)

Those helpers function will be used to replace a lot of boilerplate
using in clients.

See the tests to have a better idea of how it can be used.

For now, no API clients are refactored to use those helpers, this will
happen incrementally in future PRs.

hcloud/client_generic.go

@@ -0,0 +1,86 @@
+package hcloud
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+)
+
+func getRequest[Schema any](ctx context.Context, client *Client, url string) (*Schema, *Response, error) {
+	req, err := client.NewRequest(ctx, "GET", url, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var respBody Schema
+	resp, err := client.Do(req, &respBody)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return &respBody, resp, nil
+}
+
+func postRequest[Schema any](ctx context.Context, client *Client, url string, reqBody any) (*Schema, *Response, error) {
+	reqBodyBytes, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	req, err := client.NewRequest(ctx, "POST", url, bytes.NewReader(reqBodyBytes))
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var respBody Schema
+	resp, err := client.Do(req, &respBody)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return &respBody, resp, nil
+}
+
+func putRequest[Schema any](ctx context.Context, client *Client, url string, reqBody any) (*Schema, *Response, error) {
+	reqBodyBytes, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	req, err := client.NewRequest(ctx, "PUT", url, bytes.NewReader(reqBodyBytes))
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var respBody Schema
+	resp, err := client.Do(req, &respBody)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return &respBody, resp, nil
+}
+
+func deleteRequest[Schema any](ctx context.Context, client *Client, url string) (*Schema, *Response, error) {
+	req, err := client.NewRequest(ctx, "DELETE", url, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var respBody Schema
+	resp, err := client.Do(req, &respBody)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return &respBody, resp, nil
+}
+
+func deleteRequestNoResult(ctx context.Context, client *Client, url string) (*Response, error) {
+	req, err := client.NewRequest(ctx, "DELETE", url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return client.Do(req, nil)
+}

hcloud/client_generic_test.go

@@ -0,0 +1,115 @@
+package hcloud
+
+import (
+	"io"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/hetznercloud/hcloud-go/v2/hcloud/exp/mockutil"
+	"github.com/hetznercloud/hcloud-go/v2/hcloud/schema"
+)
+
+func TestGenericRequest(t *testing.T) {
+	t.Run("get", func(t *testing.T) {
+		ctx, server, client := makeTestUtils(t)
+
+		server.Expect([]mockutil.Request{
+			{
+				Method: "GET", Path: "/resource",
+				Status: 200,
+				JSON:   schema.ActionGetResponse{Action: schema.Action{ID: 1234}},
+			},
+		})
+
+		respBody, resp, err := getRequest[schema.ActionGetResponse](ctx, client, "/resource")
+		require.NoError(t, err)
+		require.NotNil(t, resp)
+		require.NotNil(t, respBody)
+
+		require.Equal(t, int64(1234), respBody.Action.ID)
+	})
+
+	t.Run("post", func(t *testing.T) {
+		ctx, server, client := makeTestUtils(t)
+
+		server.Expect([]mockutil.Request{
+			{
+				Method: "POST", Path: "/resource",
+				Want: func(t *testing.T, r *http.Request) {
+					bodyBytes, err := io.ReadAll(r.Body)
+					require.NoError(t, err)
+					require.JSONEq(t, `{"hello": "world"}`, string(bodyBytes))
+				},
+				Status: 200,
+				JSON:   schema.ActionGetResponse{Action: schema.Action{ID: 1234}},
+			},
+		})
+
+		respBody, resp, err := postRequest[schema.ActionGetResponse](ctx, client, "/resource", map[string]string{"hello": "world"})
+		require.NoError(t, err)
+		require.NotNil(t, resp)
+		require.NotNil(t, respBody)
+
+		require.Equal(t, int64(1234), respBody.Action.ID)
+	})
+
+	t.Run("put", func(t *testing.T) {
+		ctx, server, client := makeTestUtils(t)
+
+		server.Expect([]mockutil.Request{
+			{
+				Method: "PUT", Path: "/resource",
+				Want: func(t *testing.T, r *http.Request) {
+					bodyBytes, err := io.ReadAll(r.Body)
+					require.NoError(t, err)
+					require.JSONEq(t, `{"hello": "world"}`, string(bodyBytes))
+				},
+				Status: 200,
+				JSON:   schema.ActionGetResponse{Action: schema.Action{ID: 1234}},
+			},
+		})
+
+		respBody, resp, err := putRequest[schema.ActionGetResponse](ctx, client, "/resource", map[string]string{"hello": "world"})
+		require.NoError(t, err)
+		require.NotNil(t, resp)
+		require.NotNil(t, respBody)
+
+		require.Equal(t, int64(1234), respBody.Action.ID)
+	})
+
+	t.Run("delete", func(t *testing.T) {
+		ctx, server, client := makeTestUtils(t)
+
+		server.Expect([]mockutil.Request{
+			{
+				Method: "DELETE", Path: "/resource",
+				Status: 200,
+				JSON:   schema.ActionGetResponse{Action: schema.Action{ID: 1234}},
+			},
+		})
+
+		respBody, resp, err := deleteRequest[schema.ActionGetResponse](ctx, client, "/resource")
+		require.NoError(t, err)
+		require.NotNil(t, resp)
+		require.NotNil(t, respBody)
+
+		require.Equal(t, int64(1234), respBody.Action.ID)
+	})
+
+	t.Run("delete no result", func(t *testing.T) {
+		ctx, server, client := makeTestUtils(t)
+
+		server.Expect([]mockutil.Request{
+			{
+				Method: "DELETE", Path: "/resource",
+				Status: 204,
+			},
+		})
+
+		resp, err := deleteRequestNoResult(ctx, client, "/resource")
+		require.NoError(t, err)
+		require.NotNil(t, resp)
+	})
+}

hcloud/client_test.go

@@ -15,9 +15,24 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/hetznercloud/hcloud-go/v2/hcloud/exp/mockutil"
 	"github.com/hetznercloud/hcloud-go/v2/hcloud/schema"
 )
 
+func makeTestUtils(t *testing.T) (context.Context, *mockutil.Server, *Client) {
+	ctx := context.Background()
+
+	server := mockutil.NewServer(t, nil)
+
+	client := NewClient(
+		WithEndpoint(server.URL),
+		WithRetryOpts(RetryOpts{BackoffFunc: ConstantBackoff(0), MaxRetries: 5}),
+		WithPollOpts(PollOpts{BackoffFunc: ConstantBackoff(0)}),
+	)
+
+	return ctx, server, client
+}
+
 type testEnv struct {
 	Server *httptest.Server
 	Mux    *http.ServeMux