add new list command (#97)

api/client.go

@@ -6,26 +6,31 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"net/url"
 )
 
-type StatusError struct {
-	StatusCode int
-	Status     string
-	Message    string
+type Client struct {
+	base    url.URL
+	HTTP    http.Client
+	Headers http.Header
 }
 
-func (e StatusError) Error() string {
-	if e.Message != "" {
-		return fmt.Sprintf("%s: %s", e.Status, e.Message)
+func checkError(resp *http.Response, body []byte) error {
+	if resp.StatusCode >= 200 && resp.StatusCode < 400 {
+		return nil
 	}
 
-	return e.Status
-}
+	apiError := StatusError{StatusCode: resp.StatusCode}
 
-type Client struct {
-	base url.URL
+	err := json.Unmarshal(body, &apiError)
+	if err != nil {
+		// Use the full body as the message if we fail to decode a response.
+		apiError.Message = string(body)
+	}
+
+	return apiError
 }
 
 func NewClient(hosts ...string) *Client {
@@ -36,9 +41,60 @@ func NewClient(hosts ...string) *Client {
 
 	return &Client{
 		base: url.URL{Scheme: "http", Host: host},
+		HTTP: http.Client{},
 	}
 }
 
+func (c *Client) do(ctx context.Context, method, path string, reqData, respData any) error {
+	var reqBody io.Reader
+	var data []byte
+	var err error
+	if reqData != nil {
+		data, err = json.Marshal(reqData)
+		if err != nil {
+			return err
+		}
+		reqBody = bytes.NewReader(data)
+	}
+
+	url := c.base.JoinPath(path).String()
+
+	req, err := http.NewRequestWithContext(ctx, method, url, reqBody)
+	if err != nil {
+		return err
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Accept", "application/json")
+
+	for k, v := range c.Headers {
+		req.Header[k] = v
+	}
+
+	respObj, err := c.HTTP.Do(req)
+	if err != nil {
+		return err
+	}
+	defer respObj.Body.Close()
+
+	respBody, err := io.ReadAll(respObj.Body)
+	if err != nil {
+		return err
+	}
+
+	if err := checkError(respObj, respBody); err != nil {
+		return err
+	}
+
+	if len(respBody) > 0 && respData != nil {
+		if err := json.Unmarshal(respBody, respData); err != nil {
+			return err
+		}
+	}
+	return nil
+
+}
+
 func (c *Client) stream(ctx context.Context, method, path string, data any, fn func([]byte) error) error {
 	var buf *bytes.Buffer
 	if data != nil {
@@ -142,3 +198,11 @@ func (c *Client) Create(ctx context.Context, req *CreateRequest, fn CreateProgre
 		return fn(resp)
 	})
 }
+
+func (c *Client) List(ctx context.Context) (*ListResponse, error) {
+	var lr ListResponse
+	if err := c.do(ctx, http.MethodGet, "/api/tags", nil, &lr); err != nil {
+		return nil, err
+	}
+	return &lr, nil
+}