Setup client

ebay.go

@@ -0,0 +1,143 @@
+package ebay
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+)
+
+const (
+	baseURL        = "https://api.ebay.com/"
+	sandboxBaseURL = "https://api.sandbox.ebay.com/"
+
+	headerEndUserCtx = "X-EBAY-C-ENDUSERCTX"
+)
+
+// BuyAPI regroups the eBay Buy APIs.
+//
+// eBay API docs: https://developer.ebay.com/api-docs/buy/static/buy-landing.html
+type BuyAPI struct {
+	Browse *BrowseService
+}
+
+// Client manages communication with the eBay API.
+type Client struct {
+	client  *http.Client // Used to make actual API requests.
+	baseURL *url.URL     // Base URL for API requests.
+
+	// eBay APIs.
+	Buy BuyAPI
+}
+
+// NewClient returns a new eBay API client.
+// If a nil httpClient is provided, http.DefaultClient will be used.
+func NewClient(httpclient *http.Client) *Client {
+	return newClient(httpclient, baseURL)
+}
+
+// NewSandboxClient returns a new eBay sandbox API client.
+// If a nil httpClient is provided, http.DefaultClient will be used.
+func NewSandboxClient(httpclient *http.Client) *Client {
+	return newClient(httpclient, sandboxBaseURL)
+}
+
+// NewCustomClient returns a new custom eBay API client.
+// BaseURL should have a trailing slash.
+// If a nil httpClient is provided, http.DefaultClient will be used.
+func NewCustomClient(httpclient *http.Client, baseURL string) (*Client, error) {
+	if !strings.HasSuffix(baseURL, "/") {
+		return nil, fmt.Errorf("BaseURL %s must have a trailing slash", baseURL)
+	}
+	return newClient(httpclient, baseURL), nil
+}
+
+func newClient(httpclient *http.Client, baseURL string) *Client {
+	if httpclient == nil {
+		httpclient = http.DefaultClient
+	}
+	url, _ := url.Parse(baseURL)
+	c := &Client{client: httpclient, baseURL: url}
+	c.Buy = BuyAPI{
+		Browse: (*BrowseService)(&service{c}),
+	}
+	return c
+}
+
+type service struct {
+	client *Client
+}
+
+// Opt describes functional options for the eBay API.
+type Opt func(*http.Request)
+
+// NewRequest creates an API request.
+// url should always be specified without a preceding slash.
+func (c *Client) NewRequest(method, url string, opts ...Opt) (*http.Request, error) {
+	u, err := c.baseURL.Parse(url)
+	if err != nil {
+		return nil, err
+	}
+	req, err := http.NewRequest(method, u.String(), nil)
+	if err != nil {
+		return nil, err
+	}
+	for _, opt := range opts {
+		opt(req)
+	}
+	return req, nil
+}
+
+// Do sends an API reauest and stores the JSON decoded value into v.
+func (c *Client) Do(ctx context.Context, req *http.Request, v interface{}) error {
+	resp, err := c.client.Do(req.WithContext(ctx))
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if err := CheckResponse(resp); err != nil {
+		return err
+	}
+	if v == nil {
+		return nil
+	}
+	return json.NewDecoder(resp.Body).Decode(v)
+}
+
+// An ErrorData reports one or more errors caused by an API request.
+//
+// eBay API docs: https://developer.ebay.com/api-docs/static/handling-error-messages.html
+type ErrorData struct {
+	Errors []struct {
+		ErrorID     int      `json:"errorId,omitempty"`
+		Domain      string   `json:"domain,omitempty"`
+		SubDomain   string   `json:"subDomain,omitempty"`
+		Category    string   `json:"category,omitempty"`
+		Message     string   `json:"message,omitempty"`
+		LongMessage string   `json:"longMessage,omitempty"`
+		InputRefIds []string `json:"inputRefIds,omitempty"`
+		OuputRefIds []string `json:"outputRefIds,omitempty"`
+		Parameters  []struct {
+			Name  string `json:"name,omitempty"`
+			Value string `json:"value,omitempty"`
+		} `json:"parameters,omitempty"`
+	} `json:"errors,omitempty"`
+	Response *http.Response
+}
+
+func (e *ErrorData) Error() string {
+	return fmt.Sprintf("%s %s: %d %+v", e.Response.Request.Method, e.Response.Request.URL,
+		e.Response.StatusCode, e.Errors)
+}
+
+// CheckResponse checks the API response for errors, and returns them if present.
+func CheckResponse(resp *http.Response) error {
+	if s := resp.StatusCode; 200 <= s && s < 300 {
+		return nil
+	}
+	errorData := &ErrorData{Response: resp}
+	_ = json.NewDecoder(resp.Body).Decode(errorData)
+	return errorData
+}